Could lead to significant efficiency gains for EV's, because 1/4 of the motor weight means better power-to-weight ratio... a lot of things will automatically get better.
YASA was founded in 2009, a spin out from Oxford University following the PhD of founder and still CTO, Dr Tim Woolmer.
"Over the decades that followed both of these technologies were explored. But despite the potential for weight reduction, smaller size, shorter axle length and increased torque, it was the difficulty in manufacturing the axial flux technology that limited its commercial viability, because the motor could not be made by stacking laminations, as with radial machines."
"The breakthrough innovation came by segmenting the axial flux motor in discrete "pole-pieces", so the motor could be manufactured using Soft Magnetic Composite material.
SMC can be pressed at low cost into a wide variety of 3D shapes. This removed the need for the complex laminations, overcoming the major manufacturing challenge of the axial flux machine."
"In 2025, after a £12m investment, YASA opened the UK's first axial-flux super factory, in Oxfordshire.
The opening of this facility boosts YASA’s manufacturing capacity, setting new benchmarks in e-motor technology and quality, and enabling production to scale beyond 25,000 units per year."
This is awesome. Lighter motors also make electric flight more viable
> Could lead to significant efficiency gains for EV's, because 1/4 of the motor weight means better power-to-weight ratio... a lot of things will automatically get better.
EV motors are already lightweight. The electric motor in a vehicle like a Tesla Model 3 already weighs less than you do. Reducing that one component by 75% would be a weight savings equivalent to about a half of a passenger.
Not a significant efficiency improvement for vehicles that weigh over 3000lbs (or double that for many EVs).
Every little bit helps, but this isn’t a game changer.
Not a game changer but I wonder if ligher motors allow you to do things like have one motor per drive wheel, removing the need for differential gearboxes?
Then you can do clever things with traction control without having to use the ABS system to brake the drive wheels.
Or dramatically change the turning circle on big cars and vans. Maybe even reduce the size and weight of the braking system by taking on some of that role.
Putting the motors in the wheel is bad for a separate reason: Unsprung weight.
Every ounce you have in the hubs that don't float on the suspension reduces certain suspension attributes. You end up with a crappier ride and poor performance.
Yes, I agree. I was careful about how I worded this to avoid saying anything about the motors actually being in the wheels for this reason.
Although, I guess at some point in the future if we can get the weight down low enough and the strength of the motor high enough we could replace the existing braking system with a motor for the same weight penalty we already pay.
In an ideal world all the energy from breaking would be used for regen anyway.
I'm not sure how close we are to that but it's an interesting thought experiment thinking about the trade offs we might be able to make in future.
If the motors are light enough, though, that might be acceptable... especially if they can make an even smaller version for that application. (You probably don't need 750 kw on each wheel.)
I would expect that lighter motor components would potentially allow weight reduction in load bearing components. Not an advantage for SUV-type cars, but for light and ultralight vehicles it could add up to more weight saving and longer ranges.
> It drops a buck fifty per motor. That IS a game changer.
You’re reading their marketing material. You have to think of this like all of those PR releases you’ve seen over the years about new battery technology that is 4X smaller or new hard drive tech that is 10X more efficient. The real world improvements aren’t going to be as big as their one lab test.
A Model 3 motor is already well under 150lbs, unless you start including ancillaries like the inverter and power transmission parts.
They’re not dropping “a buck fifty” from typical EV motors.
I'm not reading anyone's marketing material. If you want to dispute the shipping weight, feel free to correct this website whom I assume charges for shipping based on weight [0]. I'm sure they'd love to know they have it wrong.
According to purchasable equipment, the Model 3 engines weight ~175 lbs. If that's wrong, that's on them for claiming it. Subtract 28 lbs from that and you're at 147 lbs. That is very close to 150 lbs.
That’s a drive unit, which is more than the motor. Read the description:
> This kit includes the Tesla motor, inverter, gear box, power cables and drive shafts.
Drive shafts, gearbox, power cables, inverter. Also includes the mounts, which is likely not factored into the lab calculations for this marketing material.
You cannot drop 150lbs from the Model 3 motor because it doesn’t even weigh 150lbs.
You're missing the forest for the trees. Dropping 10 lbs per motor is HUGE. Dropping 30 is amazing. Whatever is dropped, it's significant. Pretend that it isn't all you want, but anyone doing production work knows how important this is.
I'm happy to compare apples to apples when we can do that, and if you want me to say I was wrong about the Tesla motor size I'm happy to say that I was just going by what was available on the internet and skipped the details. But I did so in service of a point which you still haven't actually engaged with beyond "Nu uh!".
Auto makers could drop 10lbs, 100lbs or even more from every EV right now by choosing more expensive materials, more expensive manufacturing processes, or simply cutting back on amenities.
10lbs is not significant in the grand scheme of things. The real question is how much it costs, what are the tradeoffs, and how practical is it.
> But I did so in service of a point which you still haven't actually engaged with beyond "Nu uh!".
That’s not a fair take on what I’ve been posting at all. I said every little bit helps, but pointed out that motor sizes are already small.l
10 lbs per motor in an aircraft is huge. And the fact that they can do it WITHOUT having to use more expensive materials or manufacturing or amenities is the thing that is huge about it.
It's a fair take on your responses because talking about a SINGLE motor is missing the point. You're not engaging with the actual point that OP made, you're trying to dispute OP by engaging in your own point about what difference this would make in single-motor cars, instead of what difference it will make in general.
Exactly. I was very surprised to find out a fully loaded 40 ton electric truck only uses ~100kw / 100km ( https://www.youtube.com/@electrictrucker ) when my 2 ton Volvo averages 20-22kw/100km on road trips.
That “2 ton” Volvo needs to be able to accommodate up to an extra ~1 ton of passengers and cargo which means it’s paying many of the weight penalties of a 3+ ton vehicle. Beyond that at highway speeds ~5x the range from a vehicle weighing ~19x as much suggests shows weight is a critical factor even if it isn’t the only factor.
Compare things at slower speeds and weight plays an increasing large role.
I wish more people on the road realized the extent to which weight reduction improves all aspects of the driving experience... it really does compound unlike any other change that you can make to a vehicle. IMO heavy vehicles are a scam and the antithesis of the direction we should be moving.
I agree with you however I believe weight and safety are in a complex relationship right now, which has nothing to do with performance and handling.
Unfortunately I feel much less safe in a Fiat 500 when a significant portion of cars in the road weigh nearly 3 tonnes and perhaps can't even see me. I suspect most people are in SUVs because they're the pragmatic trade off between safety and convenience, not because they were hoping for excellent performance.
Yup, it's an arms race to see who can buy the biggest vehicle so that they can see over the second biggest vehicle and survive a collision with it.
But small cars are only unsafe because of that discrepancy between the largest and smallest cars, and it's not just weight, but height difference. It's possible to survive crashes at very extreme speeds in very light cars if they are designed to work that way (see: F1 crash g-force). Not so much if you literally get run over.
The culture needs to change. A vehicle is not a living room. The driver's seat is not a sofa. You don't need a TV in the dashboard. You don't need 8 seats when 7 of them are unoccupied 90% of the time. You don't need to go into debt to buy a land yacht.
So yeah... you're right, but it's a bummer that we've arrived at this situation.
> In a crash, the fatality rate of the occupants of the heavy pickup truck is about half that of the compact car. But they are also far more dangerous to the fatality rate of people in other cars.
> The fatality rate is roughly seven times higher when colliding with a heavy pickup truck than with a compact car. As the weight of your car increases, the risk of killing others increases dramatically. For every life that the heaviest 1% of SUVs and trucks save, there are more than a dozen lives lost in other vehicles.
Unfortunately car safety is only evaluated in terms of safety for the occupants. Not safety of society.
Maybe... I think it would definitely help. I think just driving a smaller car that puts you in control might cause a lot of people to switch. I know that when I've done the opposite; gone from a very performance oriented car to a random person's SUV, I've felt extremely unsafe comparatively in breaking, merging, changing lanes, parking, etc. etc. I think most people just have little experience to compare it to anymore.
I also think it's odd that people don't already choose other options w/o a tax in place, considering the price of a bigger vehicle is almost always just going to be higher because of materials and a bunch of other factors.
A basic BMW 5 series is over 2 tonnes, with the top spec model tipping the scales at 2.5 tonnes. I mean I agree with the general sentiment but it's not just SUVs that need to go on a diet. Everything is getting heavier and heavier and heavier.
I see the same trend. My thoughts: 2 tonnes of shit sells for more than 1 tonne of shit. 650 HP entices a lot more people than 1,200kg. I usually have to dig to find the weight of the vehicle. It's a consumer education problem more than anything imo.
> I wish more people on the road realized the extent to which weight reduction improves all aspects of the driving experience
This is a blanket statement and completely untrue. Good driving experience is directly correlated to TRACTION, not just weight. And traction isn't just a function of weight - it also is affected by center of gravity, friction between the wheels and the road. Traction is what gives you the perception of being in control of the car.
I used to own two cars of the exact same model - one petrol and one diesel. The petrol is lighter in weight, about 100+ kgs lighter than the diesel variant. And the driving experience on that is slightly scary especially on roads with strong winds. In fact, it is so light that if you drive over tiny puddles or rumbles strips, the car will sway sideways. The diesel always feels more planted because it is front-heavy, thus adding more traction to the front wheels (both are FWDs). I always prefer the diesel for longer drives because of the heft and confidence it provides.
I get what you're saying, but tire technology has improved traction so greatly in the last decade that we can definitely take the slight loss in maximum theoretical traction for the massive benefits in other areas. There is also the question of what "maximum traction" is... what scenario are we talking about? Straight line acceleration from a dig or skidpad turning at a high speed? If we're turning at all then the momentum (which increases w/ mass) of the vehicle is what pulls it off course and causes the tires to break traction.
I also drive a FWD (a quite spicy one) and I break traction all the time, not because of weight, but because of torque. You can modulate torque, not weight. The biggest traction increases that I made on my FWD were when I put on sticky summer tires, the second was subtly changing front control arm geometry and bushings, and the third was adding stiffer engine mounts.
Agreed on getting tossed around in a light car though, not much can be done about that... other than making the roads better and lowering the center of gravity.
Weight is not the only thing that matters though. You also need to consider center of gravity and wheel base. A YJ Jeep Wrangler and a Honda Fit both weigh around 2700 lbs and they even have similar wheel bases but the driving experience between those 2 is night and day. A Honda Fit can take a turn at speed without feeling like you're going to go flying. You'll feel like you're able to flip making a turn going 20 mph in a YJ.
This is why the first performance mod that most people put on their cars is an adjustable coil over suspension. Dropping the car down by an inch or 2 changes has just as much of an impact as shedding some weight.
Ironically, most people put lift kits on Jeeps but that also usually comes with widening the wheel base and putting on larger wheels/tires.
Lifting an off road vehicle isn't ironic at all, nearly every characteristic that makes a vehicle good on road makes it bad off road and vise versa.
Increased height makes for increased ground clearance and improved break over angle. Sway bars are another suspension component that's great for reducing body roll on road at speed, but reduces articulation and ground contact off road. Differential lockers also negatively impact turning radius, and cause tire chirp, wear, and oversteer under throttle on road, while increasing traction off road.
What's silly is daily driving an off road vehicle on road, especially if you never take it off road.
You are correct, ideally you would do both. My car is lowered on coilovers, I also have front and rear sway bars, but weight reduction is so much more than just handling.
I didn't realize that Jeep was so light... pretty nice actually, but yeah, that's just an application mismatch. People buy Jeeps that will never see even a dirt road in their lives. Then they get on a dirt road once or twice and say, "Look what it can do!" Sure... a rally car would be much better. In order for the Jeep to come into its own you need to be doing something that requires ground clearance... that's basically their singular purpose: rock crawling (which almost no one does).
It's not at all about looks, it's about a different kind of handling, for off road, that's mutually exclusive with on road handling.
Yes, some people choose to emulate off road appearances, such as with fake bead locks and then only ever drive their vehicle on road. That doesn't discount the fact that there are a great many explicit choices you can make in designing and building a vehicle that sacrifice on road performance for off road performance.
Driving Volkswagen e-up for the first time was a very unique experience to me. My brain needed to adjust that a car can be that nimble and responsive due to its small size/weight and instant torque from the electric motor.
> In 2025, after a £12m investment, YASA opened the UK's first axial-flux super factory, in Oxfordshire.
It’s a little sad to me that fundamental innovations in electromechanical engineering like this get just a few million in investment, yet if this had been yet another derivative software startup with “AI” in the pitch, they’d probably have 10x+ or more investments being thrown at them.
Seems to me everyone wants to invest, instead, into something that can be "web scale" with low marginal cost, that is, natural monopolies. There is not enough anti-trust enforcement.
The issue with this type of motor is that it is part of the unsprung weight since it is inside the wheel. This is probably why savings here matter a lot more (or at least in a very different way) than the battery weight.
Ok, now I understand why this motor is only used in supercars - installing four (or even only two - according to https://www.mercedes-benz.de/passengercars/technology/concep..., even the AMG GT-XX has "only" three of them) hub motors with twice the power of a Tesla Model 3 in any other car would be ridiculous. So, the actual challenge is to make this motor even smaller while keeping the same power to weight ratio, so it can also be used for regular cars? That is, if they want to build something for the mass market, not only for an exclusive clientele?
I don't think their motors are axial flux, they're just large and narrow to fit inside wheels. Or at least all the images on their website depict radial flux designs.
Do e-bikes really need significantly more power than they have? They already run arguably dangerously fast for their application. Is efficiency not the primary target there?
e-bikes don't necessarily need more power but they could benefit from a smaller and lighter motor. If it becomes small enough to "disappear" in the pedal assembly for example, it would allow more design/parts commonality with normal bikes and fit more people's aesthetic criteria.
The lower weight would be definitely welcome, my ebike is comically heavy compared to a normal one and sometimes I have to carry it up flights of stairs (some German railway overpasses, grr).
Also in scooters it could fit in the wheel (since the wheel is tiny and has to spin quite quickly - no reduction gear needed vs a bike with 26-28" rims) allowing a simpler design and cost savings. But maybe in scooters they're already using in-wheel motors, I'm a bit ignorant there.
There are some advantages to hub motors in an e-bike, and if the motor and an appropriate gearing system could be made light enough the disadvantages would be reduced.
Oddly, a very large majority of current fully suspended e-bikes with rear cargo racks have those racks unsprung, which suggests that most e-bike manufacturers don’t actually care about the handling of anything other than their pure e-MTBs.
While more power may not make sense, less weight is an easy way to get more efficiency. And if you can keep the same power at a lower weight, that's a win.
Hmm. I am NOT an expert (though I ride and have owned 3 traditional motorcycles). IIUC, reducing unsprung weight is really crucial for handling -- which is why so-called "inverted" forks / front shock absorbers became basically the standard.
They don’t need this motor, but if it can be scaled down… at over 10kW/kg sustained, one could wish/hope to get 200W at 50g (disclaimer: I have no idea how this scales with size). Combine that with 1kg of a 600Wh/kg battery (https://news.ycombinator.com/item?id=45797452. Again, I have no idea how realistic that is), and you have a bicycle that’s only a little heavier than a non-electric one, but gives you a boost for 3 hours (more if you use it sparingly. If you’re cycling at leisure, 100W already is a lot of power)
Yeah, you kind of shouldn't use a Raspberry Pi to blink an LED, though. Great "Hello World" project. But there are so many ways that are cheaper, lighter, smaller and more reliable (and don't require a lengthy boot-up).
From Wikipedia on Axial Flux Motors:
>"Mercedes-Benz subsidiary YASA (Yokeless and Segmented Armature) makes AFMs that have powered various concept (Jaguar C-X75), prototype, and racing vehicles. It was also used in the Koenigsegg Regera, the Ferrari SF90 Stradale and S96GTB, Lamborghini Revuelto hybrid and the Lola-Drayson.[9] The company is investigating the potential for placing motors inside wheels, given that AFM's low mass does not excessively increase a vehicle's unsprung mass.[10] "
I think they misspoke when they said "in" the wheel, but supercars can have a separate motor for each wheel, and the closer they are to the wheel the better the torque as it's not also driving a longer shaft. The smaller the motor, the closer you can get.
I guess if you can make the motor and a suitable reduction box lighter than the equivalent bearing and driveshaft combination you could make the suspension arms mechanically simpler.
By using motors at each wheel you'd eliminate the need for a differential, saving a good 40-50kg or so. Of course, if you kept the drive shafts and put the motor and reduction box in the middle, you'd be able to use inboard brakes and save a lot of unsprung weight!
There are cars with inboard brakes, although not recently. From a packaging point of view putting them out at the wheel makes sense, since there's a lot of space you're not using otherwise.
It's hard to fit inboard brakes to front wheel drive cars because there's so little space but Citroën managed it with the 2CV and various derivatives, and the GS/GSA/Birotor family. They had an inline engine with a very compact gearbox behind, with the brake discs (drums, on very early 2CVs) right on the side of the gearbox.
You got lower unsprung weight and possibly more usefully the kingpin was aligned with the centre of the tyre, so when you steered the tyre turned "on the spot" rather than rotating through a curve.
Some old Jags and Alfas had inboard discs on the rear axle, which was of course rear wheel drive. They were a bit of a pain to get at.
I’ve generally assumed that brakes are in the wheel because they’re not all that massive, they get decent cooling airflow in the wheel, and they can produce enormous amounts of torque.
I might be wrong, but I don’t think these motors are intended to be used inside the wheel. That would add a ton of additional requirements in terms of physical durability as well as constrain optimal torque and RPM of the motor design.
I believe the Aptera was originally going to have motors in the wheels... My understanding is the the first version will forego that, as there were challenges i guess, but i think they still to eventually do that.
> This is probably why savings here matter a lot more (or at least in a very different way) than the battery weight.
Wouldn't that make it worse or just ... different. Before this the unsprung weight wouldn't have had a motor in there and now it does. Increasing the unsprung weight doesn't seem a like a good thing.
What current mass production EVs use hub motors? It seems a lot more sensible to have the motors inboard, mounted to the chassis, and drive the wheel(s) with axle shafts. It seems in my searching this is how nearly all EVs are currently designed and produced.
YASA doesn't call it a hub motor specifically but that's one place where it helps to save as much weight as possible. And for the cars most likely to have 1000+HP weight matters too. A Tesla motor weighs 100-200lbs, so saving that much weight down to 28lbs on a supercar is highly desirable.
I think large drones will be another place where a downsized version of this motor will make a huge difference, assuming the power scales nicely with size.
In-wheel application is possible, but it's important to understand that the pancake shape is only a consequence of the axial flux design and Yasa doesn't make motors in other "formats". Yasa motors shaped like this have been used in several supercars and all of them have been in-board on the axles, not in-wheel.
See also the Saab Emily GT project. Even with an older, heavier gen of these axial flux motors they found significant performance gains by controlling each wheel via its own motor.
I didn't want to put the usability of the motor into question or go into a complete evaluation of advantages/disadvantages :) This was just an explanation that weight trimming the motor might be very much worth the effort - even if it somewhat "insignificant" compared with savings that are possible in battery weight.
It compounds. If you have a lighter more efficient motor you need a smaller battery for the same range, that combined weight loss means you meed lighter brakes etc etc, and because the car is now lighter you size of your motor you need is less.....
They claim, this compounding effect works out to basically double the effective weight saving from battery and motor.
ie if you start with saving 50kg on motor, and 50kg on battery, you end up saving 200kg over all. Still only about 10% of a typical electric car.
> If you have a lighter more efficient motor you need a smaller battery for the same range
Nitpick: You can have a lighter motor, but you're never going to have a significantly more efficient motor because existing EV motor systems are already 95% efficient or better. The electric motor is an old and refined technology.
I'm not an expert - but the axial flux design while old is been largely ignored due to manufacturing problems that have now been overcome ( so most of the dev has been on the radial flux variety ).
And apparently axial flux motors have shorter magnetic flux paths which reduces losses.
ie the efficiency gain is due to the switch from radial to axial flux - not some incremental gain on radial flux.
Having said that the efficiency gains are relatively small - 1-2%.
However again there is a compounding effect, in that the reduction of loss of energy as heat, leads to requiring less cooling - and/or the motor is able to operate a full efficiency over a wider power output range ( as heating the copper increases the electrical resistance ).
What's a bit of a shame is they are no longer an independent company ( ie wholly owned owned by Mercedes ) - so that might mean we are less likely to see these motors combined with solid state batteries any time soon.
Yea that's the thing right, the battery is so very much of the weight that optimizing the other parts are "meh" at this point. What is cool is that the 600Wh/kg solid state batteries seems like they are really finally here soon :) i.e removing 200-300kg from a car in one go will be a game changer.
Range being worse with a fully loaded car than with a lightly loaded car isn't exactly news, and not exactly limited to electric cars. I can clearly feel my old diesel struggling more when I'm driving 3 friends and with loads of heavy stuff in the back than when I'm alone. That makes the gas bill more expensive.
You probably know already, but ICE cars only convert about 20–30% of fuel energy into motion, while EVs are often +90% efficient. So when an EV has to work harder (extra battery weight or colder weather), you notice the drop in range more.
In an ICE, the same load is less visible because most energy gets wasted as heat. This is also why cold weather seems to affect EV range more.
> You probably know already, but ICE cars only convert about 20–30% of fuel energy into motion, while EVs are often +90% efficient. So when an EV has to work harder (extra battery weight or colder weather), you notice the drop in range more.
There's a kernel of truth here in that Otto engines suffer lower efficiency at part load, however I suspect the real reason is that gas car range is "good enough" and refilling is fast, so one doesn't tend to obsess about remaining range.
> This is also why cold weather seems to affect EV range more.
That's because a) some batteries suffer degraded performance at low temperature, and b) ICE cars use the plentiful waste heat for cabin heating whereas an EV needs a heat pump or even resistive heating of the cabin air.
> That's because a) some batteries suffer degraded performance at low temperature, and b) ICE cars use the plentiful waste heat for cabin heating whereas an EV needs a heat pump or even resistive heating of the cabin air.
You are making my point here actually. Combustion engines suffer from the exact same, but because they waste so much energy as heat already, less “extra” energy needs to be spent on that.
The unexpected benefit which I've noticed when switching from a small, light car to a heavier, medium EV car is that the latter doesn't drive/feel any worse when fully loaded. Makes the trips that much more pleasant.
True! If only grandma wouldn't insist on bringing 250kg of weapons and ammunition with her everywhere I'd get much better range in my EV, but alas this is the USA.
Instead of technological advancements of EV motors, we can immediately use existing pharmaceutical tech (Ozempic, GLP-1) to immediately deliver weight reduction to cars. However, this will be immediately offset by the increase in weight of weapons carried, thanks to Jevons Paradox.
Manufacturers may just keep the battery size and market the improved range instead? Smaller cars in urban and suburban environments have always had lots of benefits, but since many of them are collective in nature, it has largely fallen on tragedy of the commons, and we got larger cars with larger hoods instead.
Not true. Tesla themselves said the way they got the Model 3 to be so efficient was by optimising every single part exhaustively. It’s expensive at design stage but results in the most efficiency gains across the fleet - so worth it (especially something like the motors)
This is a negligible improvement to most things about an EV. Motors are already extremely power-dense.
There is a single exception, and it's a big one. Direct-drive, wheel-hub motors are not well-regarded right now, specifically because they increase unsprung weight (the part of the car more closely coupled to the road surface than the passenger) and this impacts handling substantially. So instead we backport a bunch of the mechanical infrastructure that transfers power from a traditional ICE engine to the four wheels. We're paying that bill already, on almost all production EVs. Quadruple the power density and simple, 1-moving-part wheel hub motors look like a lot better case versus central driveshafts and mechanical linkages.
Tesla Model Y's battery is 771 kg. The motor in Model Y weights about 45 kg, about three times as much as the motor in the article. By reducing dual motor configuration weight from 90 kg to 28 kg, we reduce total powertrain weight by 7%.
Even if motors were literally weightless and mass-less, EVs would weigh more than ICE cars.
It's like making a more efficient CPU for your phone when all the power is eaten up by the cell-modem, screen and RAM. People wonder where the practical battery life gains are and theyre miniscule in practice
That wasn't so much a criticism of the electric motor, which it sounds like they can scale down, as the Neanderthal part of my brain lighting up. Mongo like power to weight ratio.
I don't see the weight reduction being very significant.
If we take a Tesla model 3, I believe it weighs 1611kg, and the motor shows up at 80kg if you google it (no idea if this is correct). This YASA motor by comparison weighs 14kg. So, this would drop the vehicle weight by 66kg out of 1611, so that's a 4% saving.
This motor is well more than twice as powerful as the Model 3 motor, so it could eliminate the entire weight of the second motor in the higher performance models. That’s 146kg, the weight of two adults, an 11% reduction.
> Could lead to significant efficiency gains for EV's
Not really. EV's are very heavy from non-motor weight. A Model Y weighs ~4300 lbs. A motor that is 75 lbs lighter is a 1.7% savings. That's not nothing, but I wouldn't say "significant". You can do better by swapping for fancy wheels or eliminating some of the glass roof.
And really this is true up and down the electric vehicle world. Weight-sensitive applications are always going to be completely dominated by battery weight. Making the motor smaller just isn't going to move the needle.
Basically this is good tech without an application, which is why it's having to tell itself with links like this.
It’s great anywhere you want more power but are limited by space and/or weight for performance reasons. Aerospace, e-bikes, electric race vehicles, electric motorcycles.
But yeah, EVs seem weird except for racing reasons perhaps.
What I can’t figure out is how they dissipate the heat - double digits kw per kg is crazy.
The YASA axial flux motors benefit from much shorter windings and direct oil cooling which gives an unparalleled performance proposition.
A 200kW peak-power radial motor, run continuously, might typically give 50% of peak power between 80 and 100kW, as a result of thermal limitations. In contrast, a 200kW YASA motor runs continuously at 150kW thanks to the improved high-thermal-contact cooling that oil offers.
The first step to dealing with heat at high kw, is to not generate the heat you have to dissipate in the first place. Which means chasing smaller and smaller efficiency gains, because that reduces heat generated.
The more of the energy going into moving the vehicle, the less heat the motor has to handle.
Sure, but at 50kw/kg at 99% efficiency is still 500w/kg, which is cray cray. Like ‘glowing red hot shortly’ type of crazy with just passive cooling.
And there is no way this is 99% efficient.
So my question still applies. Even 98% is 1kw/kg, or 1kj/sec. or around 3C rise per second assuming the mass is 100% nice clean copper (it isn’t). Everything else will be worse.
Not even counting increasing losses with temperature, it will be a molten puddle pretty quick at that rate without some major active cooling.
I was waiting to see in the comments EXACTLY this question: There is no way to dump this heat. 1000hp? Yeah, maybe for a few seconds, even with oil coolant pumping through there. Then how to dump the heat from the oil. And further thinking, if they ever get this to be a hub motor, how in the world are they going to pump coolant through 2-4 hub motors and then to a radiator that can dump that rate of heat rise, especially since oil is a lousy coolant (relatively speaking).
Again, no, because the motor needs to be powered and the battery is vastly larger than the motor already in any of those applications. Even in RC planes, which fly for 5-6 minutes at a time, the battery is 5x or more the weight of the motor, wiring and controller logic.
The Ferrari 296 GTB weighs about 1500kg and the sports version 1300kg. For the cars YASA produces motors for it's much easier to increase the power to weight ratio by reducing weight than increasing power. I imagine an important design point for all of its components is to reduce weight.
I agree insofar as the motor is not a Big Ticket Item, opposed to ICE cars where the engine block is going to be 10% or more.
Tesla (I know) claimed a 30kg (?) weight loss on their Cybertruck (I know) just from moving their 12V systems to 48V, allowing for lighter cables at lower currents. Not all such potential is untapped, and my hunch is that there is more to be had with structural battery integration, battery cooling, and high voltage wiring.
If you put several small motors on each wheel you might get some extra weight gains in the form of less transmission needed. Cables weight less than metal structural bars. But yes you are not going to be 500kg lighter.
Depends on your definition if significance, but I think they do. Every kg of useless weight you do carry, lowers your range. But sure, on its own it is not a magic game changer for heavy electric cars.
For light weight vehicles on the other hand, it might be.
Weight reductions on an electric car are self-reinforcing. If you reduce the weight of a component, the battery can become (slightly) smaller, which again reduces weight. At a certain amount of reduction this will allow you to make the whole structure lighter, which will again allow for a smaller battery.
Also not considered is that the announcement is for 740bhp motor. The Tesla model 3 has a vehicle output of about 400 hp. I’m not sure of all the design specs, but it seems clear to me that a smaller version of these motors could suffice to drive a 3 equivalent vehicle at 1/2 the output and still be more than sufficient. So let’s say maybe 15lbs each, vs current equivalent 70lbs each. It’s not major total weight impact, but with battery advancements it will compound.
I think people are overlooking that the announcement is for a performance motor meant for the performance market at the moment because that is what the backers of YASA are most interested in because it has the highest margins and prestige. Also not mentioned is the efficiency from the simpler production line.
My impression from what I know is we are looking at an impact equivalent to direct injection engines; not revolutionary, but a major advancement of one component that has significant and consequential effects.
> This is awesome. Lighter motors also make electric flight more viable
The next innovation we need is Aerial refueling[1] for electric planes. High density swappable batteries and high altitude wind/solar plants that can swap batteries mid air. Perhaps some billionaire will develop a large fleet of these to service all flights! If no western billionaires, we just have to wait for China to develop this tech.
A sufficiently compact electric motor enables mounting it in the nose-wheel of commercial aircraft, allowing it to be driven around like a golf cart. This means the plane can taxi without the use of its engines, just the power from the APU. [1]
Also planes would not have to wait for a tug to pull back from the gate, which improves turnaround times for the airline.
You could also spin up the landing gear wheels prior to landing to massively reduce the amount of rubber transferred from tire to runway on touchdown. Rarely done today because of the weight and complexity of adding motors, but letting the ground spin up the wheel is pretty expensive both for tire wear and runway maintenance
Surely it would be easier to recharge rather than swap batteries? I wonder if in the future war will be like a turn based strategy game as everyone wait for drones to recharge before making a move.
Mid-air: yes. A boom with a charging cable or even beamed energy would be much easier.
On the ground: swapping batteries is faster, and batteries are cheaper than planes or drones. You want the expensive part back in the air as soon as possible so you don't need as many of them. On the whole this probably also simplifies logistics: in civilian aviation airport space is limited, in wartime it's easier to transport one hundred drones and two hundred battery packs to the frontline than to transport two hundred drones
That's a future thought when it comes to electric aircraft - remote/emergency refuelling. I know they have tested lasers, and even sent a megawatt in 30 seconds over a distance of a few miles, though current convention of the laser back into usable power is around 50% efficiency. All gets down to a needed leap in electricity production and wished the World would get together on fusion reactors and knock it out the park over a mad race to be the first and lock down patents.
A typical regional aircraft needs about 3MW of power to keep in cruise, and has about 50 square metre area, so 60kW per square metre. Even with 50% efficiency you're talking over 100kW/m^2
A laser over 10W has safety implications. This is 50,000 lasers all shining on the same plane.
Given your collectors are only going to be say 50% efficient, you're likely going to dumping enough wasted energy into the wings to melt the aircraft - not sure what dumping 3MW of heat energy into a plane would do over an hour, but I suspect it would stat to melt in a few seconds if you're lucky (otherwise your passengers would start getting very toasty)
At 3MW for an hour that's not a great amount of electricity that's needed - at 10c/kWh it's $300 an hour. You don't need fancy things like fusion to generate that. In the UK alone Solar is currently (in November) generating 600 times that - plus domestic installations.
The other aspect is that a smaller motor with the same power generally has higher efficiency, by necessity, since it has less heat dissipation. So higher power and higher efficiency and lower size/weight all go together. It’s a great synergy.
At this point why don't we get rid of the k prefix and write 59W/g?
Edit:
I was half joking, but various answers mention kW being standard for motors, kg being the SI unit for mass etc. All true, but as used here in a combined unit, which means "power density" it still would make sense IMO. It's not like the "59" tells you that it's a strong motor and hence you want kW to compare it to other motors. You can't, it's just a ratio (power to weigth). W/g just reads much nicer in my head. Or we could come up with a name, like for other units. Let's call it "fainpul" (short fp) for example :)
Amusingly, given the other thread in here with people sniping each other over the metric system, I'm obliged to point out that kg, not g, is the fundamental unit of mass in SI, because even metric can't get away without some silliness.
Ha! I didn't know that.
This blondie is definitely, definitely the more, um, traditional(?, oof) genus and species of American 'blondie' (no offense to blondes, I promise, as my disdain is in the direction of protection of blondes rather than broad criticism)
This discussion is all about vehicles with large batteries, but how about hybrids? With light enough and efficient enough motors, all kinds of designs might become practical:
- Toyota-style hybrid drives could be a lot lighter, and they don’t need large batteries.
- e-bikes with tiny batteries?
- Hybrid aircraft? What if there was a battery large enough for takeoff and landing, a small motor (or pair for redundancy) for cruising and to recharge the battery, and motors and fans or propellers wherever is best from an aerodynamic perspective.
While I see Toyota-style hybrids as designed for efficiency, there's also the performance hybrids like the new Porsche 911 T-hybrid where an electric motor spins up the turbocharger to eliminate lag while another integrated into the gearbox adds power. There is no "EV mode" so it doesn't need a large battery.
Arguably the most important characteristic of a sports car is light weight, so lighter motors would be immediately useful there.
The size of this motor is moderately interesting, but the power density doesn't really matter for most of the things you just mentioned. Almost every one of them is limited by the amount of batteries you can put in for both weight and power output reasons.
The questions I have mostly centre around how much precision of power delivery it has - it is an all or nothing proposition, can it deliver 0.1% smoothly for real world use, and what is the MTBF / duty cycle / failure mode? I would imagine the last thing anyone would want is a locked wheel, or only one wheel delivering that much power. I know this is unlikely, but as someone with a 22-year-old ICE vehicle I do tend to take the long view on these things and want to know how they will fail as much as how they work. Same applies to the Tesla motors - is there much information on failure modes publicly available?
Not sure about that, but if you ask me, a really small dog only weighs up to 7 pounds - or otherwise said, this motor weight as much as four fat Chihuahuas ( https://en.wikipedia.org/wiki/Chihuahua_(dog_breed) )
Lol. I was confused by it also. I have no idea how much is 28 pounds, and I could imagine how a small dog can be anything from 1 kg to 10 kg. It happens that the motor weight is ~13kg, but I'm still not sure that 13kg dog counts as "small".
Ok so whats the catch with the technology? Its more powerful, smaller, all readily available materials. Some kind of strange shape, longevity challenge? Difficult to make so costs are tough to bring down?
Just noticed that they are owned by mercedes benz- they will kill it accidentally. Corporate wont be able to roll it out. They will try and capture all the value and kill its potential
Axial flux motors are difficult and expensive to make.
Motors need to be made of laminated steel sheets to reduce parasitic eddy currents. The laminations need to be thin in the direction of the direction of the flux. For radial flux motors you just punch out a shape and stack a bunch of sheets up. For axial flux you have to wind a strip: https://15658757.s21i.faiusr.com/2/ABUIABACGAAgmviFqAYozvPw-...
Each layer of that strip has a different cut in it, so its much more complicated to make. The shape and manufacturing method typically impacts efficiency; YASA avoids that by spending more money. Efficiency is an unavoidable requirement of high power density- heat is the limiting factor, and going from 98% to 96% efficient means double the heat.
The mechanical demands on the motor are also much higher- radial flux is balanced since the magnetic force pulls the rotor from opposite sides. Axial flux motors are usually one-sided, so the magnets are trying to pull the rotor and stator together with incredible force. That also makes vibrations worse. Extremely strong, expensive bearings are required to handle it. With permanent magnet rotors you need a jig to lower the rotor into place; they can't be assembled by hand. That also makes maintenance more difficult and expensive.
>> Each layer of that strip has a different cut in it, so its much more complicated to make.
You can roll a spool of that material and then machine the shape out of it. I've seen this done for axial flux motors. There are other approaches as well, and the cost differences get even smaller if you throw automation at the production process. I used to believe axial flux motors were one of those oddities that won't win in the end, but now that I work with them I'm not so sure. They are at least competitive with radial flux machines.
Can you (or anyone) explain where the power density improvement comes from with axial flux? When I work through the first-order math it seems like it should come out the same as radial flux. Is it just that the geometry allows better cooling from the coils? Or the use of grain oriented steel?
It's easy to forget that most of the weight in an electric car is the battery. It's ICE cars where a lot of the weight is in the motor.
That being said, could this be adapted so that a 2.8lb motor produces 100 hp? That would allow putting a small motor in each wheel, thus completely eliminating axels, driveshafts, and allow recapturing the space they used to occupy. It also wouldn't significantly impact unsprung weight.
Second, don't forget that you're trading one complexity for another. Eliminate a drive shaft and you still have to get power to the wheel somehow, which means now you're running high power electrical cable in a very dynamic environment with exposure to the elements. On top of that, you need to cool the electric motor, so you're probably running some kind of fluid out to it. Not that it isn't a solvable problem, but it probably doesn't reduce the weight much, if at all, when the system is all added up. You'll find that while you eliminate an axle, you still need to mechanically connect the two wheels together (look at the rear subframe on an FWD car) for strength, which also reduces the weight loss. Then the steering on the front... etc.
Until a more significant change than this motor (where maybe a 2.8lb motor could produce 100hp without needing active cooling), we're better off with "inboard" motors still.
People used to say they would only get a Tesla if it was offered with a manual transmission.
It's easy to laugh at, but there are still many people who haven't shifted, in their mind, to the differences.
Even after driving EVs for over a decade, I still need to shift. My habit is to turn the car off and close the garage inside the car. My new EV only controls the garage if it's on, so I had to get used to closing the garage with the car on. There's still a part of my brain that screams "but carbon monoxide" every time I do it.
It would almost have to be very efficient -- they're saying it can do something like 500HP continuous, and it doesn't have enormous fins all over it for cooling.
Exactly my thought as well. You can have all the horsepower you want but if it doesn't convert the electricity efficiently, it's not going to be useful for normal consumer cars.
Peak power is a number that can be manipulated. You just dump short circuit current into a winding. Even if that peak lasts for 1 microsecond, you can "claim" eye-watering horsepower numbers.
I wonder if we defined peak as sustained peak over 100 milliseconds, or some more meaningful number, what that would do to the claims. You aren't really generating meaningful torque over 1 microsecond.
I sort of wonder how well these things can be scaled down.
Wheel hub motors are obviously bad, for harshness reasons, but if you could have a motor like this weighing 1-2 kg, and put one on each wheel, that'd be okay.
Power-wise this would be okay if things are linear. 26 kW per wheel sustained power output is more than enough for a light car. The question is what torque a scaled-down machine can be expected to have.
I'm wondering if it would make sense to integrate the rim, motor and wheel bearing into a single assembly to save weight and cost. That combined with the weight and packaging benefits of not having half shafts and differentials might make it worth it. Plus there can be additional benefits, like the extra maneuverability that ZF Easy Turn and Hyundai's e-Corner have demonstrated.
30kW sustained/60 kW per wheel peak power is easily enough even for large passenger vehicles. Sustained could take 3 ton vehicle up a 10% grade at 120 km/h.
Thanks. Do you also happen to know the power density of the motors in the average EV car? Because the article uses "nr of Tesla Model 3" as a unit, which is meaningless without further details about it power density.
It is great that Mercedes-Benz now owns a highly performant electric engine. But is this just an impressive lab breakthrough, or can it work in the real world for their cars? Which means enduring from freezing to high temps, hours of sustained driving, and years of that (or equivalent endurance testing).
It's not a lab model (according to the article), but it's likely aimed at performance cars. For consumer cars, 150 KW / 200 HP is enough and efficiency is more important than weight.
Of course, when consumer car efficiency increases, they won't necessarily get higher ranges because the manufacturers will instead try to downsize the battery.
> It can also sustain between 350 and 400 kilowatts (469–536 horsepower) continuously, meaning it’s not just built for short bursts, as it can deliver massive power all day long.
> "There has been significant progress in the construction of molecular motors powered by light and by chemical reactions, but this is the first time that electrically-driven molecular motors have been demonstrated, despite a few theoretical proposals," says Sykes. "We have been able to show that you can provide electricity to a single molecule and get it to do something that is not just random."
"something that is not just random" ==> Probably a long way away from something in production. I wouldn't hold off on any urgent transportation needs waiting on this tech.
Axial flux motors are so next level. Very little power needed per rpm. I’ve built a few tiny ones for FPV and they are a joy to work with. I’ll die a happy man if I never have to coil again.
Their website claims "4 X more torque and double the power densities of current technologies".
A bit handwavy, but given the inherent torque advantage of electric, I doubt torque is an issue. If anything, a lot of EVs would probably do better with a touch less torque.
It's cool, but I think deploying motors without rare earth materials will be more impactful. The Nissan Ariya was ill-fated for other reasons, but it had a EESM motor that is easier to cool, more efficient at speed, and cheaper. That's where motor tech is headed. Power density just isn't terribly important in current applications, at least not past current sota.
EV motors are not that heavy. Ok it is 1/4 of a tesla motor but would that make much of a difference compared to the rest of the car since the weight of an EV motor is in single % of the entire weight.
Sounds like it could be more important for drones?
I do not know why people still think Tesla is a unique company. They are a regular car company now. Nothing more, nothing less. Yes, they disrupted the market and the reward is a standalone, viable car company. That is a huge achievement. But their disruption and uniqueness is gone. The rest of the car industry woke up and all are producing many more EV variants and EV cars in total.
One of my fundamental criticisms of Elon musk performance as a CEO. The vast stock market price and valuation should enable these sorts of transactions.
It would enable Tesla to diversify operations move into applying its technology on a mass-market basis to hybrids without "damaging" the "purity" of the Tesla brand.
It would enable more marques to target specific economic bands, international markets, etc.
But no we basically have a car company that makes two cars.
Yet Another Sale Abroad. Not a criticism of the YASA team. It’s hard to scale a company in the UK and foreign investment is a good thing in general. But still frustrating that the UK was unable to offer the kind of investment that Mercedes could to keep a company British.
I wonder if Americans don't have a mental image for measurement units so that they alway use some physical object as a reference. Sure, its useful to use a common object as a reference but I don't see that much often in other places.
Most people usually understand what it means something to be 20 meters, 5kg or 2 liters intuitively. Like, when I hear that something is 60m tall I intuitively think if it as 20 story apartment building and don't benefit from the extra info about how this is like 18 elephants stacked on each other.
I'm also European and don't get these olympic swimming pool or whatever comparisons. I'd have to look up how many m3 of water they contain or what's the length/depth in meters are to make sense of it.
Newspapers in my country don't make these silly comparisons.
But yeah, to be fair, when hearing about Starship I had to look up our TV tower height to identify whether Starship is taller or not. It disappointed me that it's not.
Yeah, height is easier to grasp when correlating in terms of x story apartment buildings.
Yes I'm always a bit dumbfounded by this behavior as well.
They always use weird stuff and I never have the intuition of the actual size, especially since the definition can vary depending on context.
In this case, what is actually considered to be a small dog? To me it would be something that is close to the size of a cat but since it's about 13kg, it can't be that small, so that's more like a medium dog (I'm not certain, but I have a feeling that if you lay out things statistically this is what you would end up with).
On the other hand, 13kg is very easy to get, that's just 13 liters of water, and it's quite easy to make a mental image for both volume and weight "feeling" that way.
American units feel so impressive and random, it is the reason they always add those weird comparisons but often they make it even worse.
Americans do not do metric. Americans can’t even balance a checkbook. Hence the small dog reference for mental “clarity”. We’re dumb. Just look at the news…
I think it may be fair? This guy[1] explains how surplus of corporate profits are a mirror image of household/govt debt. Which is a direct transfer of wealth from everyone to the super-super-rich (not the 1%, but the 0.1 - 0.01%)
[1] The chart below shows how this works. The blue line at the top shows the “surplus” of corporations: corporate income minus expenses and net investment. We know this as corporate “free cash flow.” The red line shows combined “surplus” of other sectors: government, households, and foreign trading partners – in excess of their consumption and net investment. It’s negative, so in aggregate, they’re running a deficit. That deficit is the mirror image of the corporate surplus. This isn’t an accident. It’s just accounting (I’ve excluded a few tiny items for clarity): https://www.hussmanfunds.com/comment/mc251028/
And with your bank balance instantly available on the computer in your pocket, and transactions posted in near-real-time, why would you need to worry about balancing it?
Which is why all the dumbest Americans insist that "Why didn't they teach us how to balance a check book?", while, well, they were taught that, and every single check book comes with clear and simple instructions for its use
They were also taught how to calculate loan details and the extreme power of how interest grows, but they were too busy crying "Oh this is lame, when am I ever going to use this?"
There's a cult of proud ignorance in the US. People will brag about being uneducated, illiterate, or unable to follow simple instructions.
Sure but don't they have a mental image for 80 feet for example? Why articles will almost always include something like "that like 50 chairs put next to each other" when length is mentioned.
If you were to say 100 yards, we could. That’s a football field (American football played with your… hands).
Because people in the south don’t even know the imperial system… it’s bad. They say things like “Take the road there yonder and when you see the white church, turn right, go a ways until you get to the dirt road…”
Anything outside of what they have with them, they don’t have a clue or can’t imagine it accurately. Small dog reference, there’s millions of Americans with a small dog so most just looked to their pooch when this came up. Same as if you were to say something like 50 cars. They would look outside to their Toyota Corolla and imagine 50 of them. It’s like talking to grown toddlers sometimes but that have full grown emotional states not under control. Not everyone is like this but a good 50-60% of Americans are. Just look for the Lululemon.
I know that 1kg is about 2.2lbs but that still doesn't give me the "mental clarity" of what 20kg is unless I do the conversion.
At the gym I use the pound plates and not the kilo ones. I intuitively know what the difference between 135 and 225 lbs feels like, and I don't have that same intution for kg.
All that said, I don't find the "small dog" types of analogies for weight very useful. Why not just use the same number of characters (or less) to give the weight in the other popular unit?
It helps to understand that the only freedom Americans only cared for (and the only freedom they have left from the looks of it) is the freedom to choose standards of measurement and vocabulary. This will provide historical context: https://www.youtube.com/watch?v=JYqfVE-fykk (Washington's Dream - SNL)
Huh? Britons get locked up for social media posts. Most of the world doesn’t have guns. And among the first world we’re the only ones free to go bankrupt from medical bills!
Our problems don’t stem from lack of freedom, they stem from too much of it.
You have the sort of view of America that I can only imagine comes from somebody who has never been here. I don’t know what you mean by batteries, I’m not aware of any we don’t have available.
We have the second most electric vehicles after China, and nearly all new power generation being built here is renewable. I’m not sure how you managed to turn this into some anti-American rant, but at least do a better job of it, it’s very easy.
If I were a self-respecting journalist, I would've used 3.26 gallon milk jugs. Small dog automatically goes to which breed? Chihuahua (fits in a toddlers purse) or Border Collie or Golden Retriever or Saint Bernard (needs an SUV/minivan)? 4 different classifications based on size!
Americans are very weird when it comes to metric. They often quote mobile phones as having something like "a six inch screen size but now only 12mm thick" - pick a measurement system people !
After switching to the metric system ('70-80s) some things are still measures in imperial units. If you slice some ham at a counter in a grocery store, it's in grams. You then turn around and get a pound of apples and a gallon of milk. Nuts are in grams, and soda is in liters. Also the body weight tends to be in pounds. Tools are both metric and imperial. Speeds and distances though, thank god, are metric.
All this is just kinda there and everyone's OK with it, but it is an epic mess if you think about it.
The link you're quoting, the one posted, is a second hand US report.
The primary company link is from a UK subsidiary of Mercedes-Benz and is (almost) fully metric (the fundemental units US weights are officially defined with respect to (for more than a century now)).
Earlier in the summer YASA achieved 550kW (738bhp) from a 13.1kg version of its new axial flux prototype motor, equating to an unofficial power density world record of 42kW/kg
Now latest testing of an even lighter 12.7kg version on a more powerful dynamometer has shattered this record, with a staggering 750kW (>1000bhp) short-term peak rating, resulting in a new unofficial power density record of 59kW/kg
Just those pesky trad bhp units left hanging like a chad in a Florida election . . .
That seems unlikely, a proper Brit would know that a stone is defined for body weight (14 avoirdupois pounds), Wool (14, 15, or 24 pounds depending on wool class), Wax (12 pounds), Sugar and spice (8 pounds), or for Beef and mutton (8 pounds).
( Of course Scottish Britains used 16 Scottish pounds for a Scottish stone ).
The point being that 'precious' metals used a different weight measure altogether .. (common lead often used a 12 pound stone).
Prior to the Revolution, in France alone there were allegedly 250 thousand various units in use! (All sorts of units, not just length.)
It didn't help that pre-Revolutionary France was a political Frankenstein stitched together from dozens of regions with completely different history (Celtic Brittany, Flemish Dunkirk, Germanic Alsace, Provencal South, Catalan Roussillon, Italian Nice) and thus very different local standards of everything, including measurements and law.
Unification of units removed a massive constraint on international trade and engineering. Except the US and Myanmar, of course... it is so frustrating to order anything from Myanmar e-shops, I must say. But Myanmar is at least promising to move on.
Feels like a vanity metric, electric car companies don't boast about their cars having X horsepower. Not many people care about horsepower because either way there are speed limits on the road.
I think electric motors should focus on other vectors.
Car companies, both electric and non-electric, frequently advertise rated horsepower of their vehicles, even non-performance vehicles. In the US, horsepower is one of the key metrics for a vehicle overall.
Every car listing, review and so on mentions either the bhp or kW, along with the 0-100km/h or 0-60mph which is functionally the same as listing the horsepower to weight ratio.
Yeah, but 0-60 doesn’t really matter much for EVs at this point. Even big suv/trucks are hitting supercar numbers from a few decades ago.
Cornering / handling matters. So does tire wear, and how powerful the regenerative braking is / how many motors there are. (ABS and traction control via electric powertrains is much more responsive than via brake pads).
Could lead to significant efficiency gains for EV's, because 1/4 of the motor weight means better power-to-weight ratio... a lot of things will automatically get better.
YASA was founded in 2009, a spin out from Oxford University following the PhD of founder and still CTO, Dr Tim Woolmer.
"Over the decades that followed both of these technologies were explored. But despite the potential for weight reduction, smaller size, shorter axle length and increased torque, it was the difficulty in manufacturing the axial flux technology that limited its commercial viability, because the motor could not be made by stacking laminations, as with radial machines."
"The breakthrough innovation came by segmenting the axial flux motor in discrete "pole-pieces", so the motor could be manufactured using Soft Magnetic Composite material.
SMC can be pressed at low cost into a wide variety of 3D shapes. This removed the need for the complex laminations, overcoming the major manufacturing challenge of the axial flux machine."
"In 2025, after a £12m investment, YASA opened the UK's first axial-flux super factory, in Oxfordshire.
The opening of this facility boosts YASA’s manufacturing capacity, setting new benchmarks in e-motor technology and quality, and enabling production to scale beyond 25,000 units per year."
This is awesome. Lighter motors also make electric flight more viable
> Could lead to significant efficiency gains for EV's, because 1/4 of the motor weight means better power-to-weight ratio... a lot of things will automatically get better.
EV motors are already lightweight. The electric motor in a vehicle like a Tesla Model 3 already weighs less than you do. Reducing that one component by 75% would be a weight savings equivalent to about a half of a passenger.
Not a significant efficiency improvement for vehicles that weigh over 3000lbs (or double that for many EVs).
Every little bit helps, but this isn’t a game changer.
Not a game changer but I wonder if ligher motors allow you to do things like have one motor per drive wheel, removing the need for differential gearboxes?
Then you can do clever things with traction control without having to use the ABS system to brake the drive wheels.
Or dramatically change the turning circle on big cars and vans. Maybe even reduce the size and weight of the braking system by taking on some of that role.
All for the same weight budget.
I believe that some EVs already have 1 motor per wheel such as the top of the line Rivians that are advertised as quad motor.
https://www.mbusa.com/en/vehicles/model/g-class/suv/g580w4e#...
has four electric motors
Putting the motors in the wheel is bad for a separate reason: Unsprung weight.
Every ounce you have in the hubs that don't float on the suspension reduces certain suspension attributes. You end up with a crappier ride and poor performance.
Yes, I agree. I was careful about how I worded this to avoid saying anything about the motors actually being in the wheels for this reason.
Although, I guess at some point in the future if we can get the weight down low enough and the strength of the motor high enough we could replace the existing braking system with a motor for the same weight penalty we already pay.
In an ideal world all the energy from breaking would be used for regen anyway.
I'm not sure how close we are to that but it's an interesting thought experiment thinking about the trade offs we might be able to make in future.
If the motors are light enough, though, that might be acceptable... especially if they can make an even smaller version for that application. (You probably don't need 750 kw on each wheel.)
I would expect that lighter motor components would potentially allow weight reduction in load bearing components. Not an advantage for SUV-type cars, but for light and ultralight vehicles it could add up to more weight saving and longer ranges.
The difference is when you take into consideration rotating mass, and the distribution between the stator and rotor.
It drops a buck fifty per motor. That IS a game changer.
It can make cars cheaper, or longer range, or faster, or any number of other designs based on what the manufacturer is looking for.
But to OP's point about flight - stacking 6 Tesla motors is not an option. Stacking 6 of these YASA motors? Much less weight.
> It drops a buck fifty per motor. That IS a game changer.
You’re reading their marketing material. You have to think of this like all of those PR releases you’ve seen over the years about new battery technology that is 4X smaller or new hard drive tech that is 10X more efficient. The real world improvements aren’t going to be as big as their one lab test.
A Model 3 motor is already well under 150lbs, unless you start including ancillaries like the inverter and power transmission parts.
They’re not dropping “a buck fifty” from typical EV motors.
I'm not reading anyone's marketing material. If you want to dispute the shipping weight, feel free to correct this website whom I assume charges for shipping based on weight [0]. I'm sure they'd love to know they have it wrong.
According to purchasable equipment, the Model 3 engines weight ~175 lbs. If that's wrong, that's on them for claiming it. Subtract 28 lbs from that and you're at 147 lbs. That is very close to 150 lbs.
[0] https://evshop.eu/en/electric-motors/295-tesla-model-3-drive...
That’s a drive unit, which is more than the motor. Read the description:
> This kit includes the Tesla motor, inverter, gear box, power cables and drive shafts.
Drive shafts, gearbox, power cables, inverter. Also includes the mounts, which is likely not factored into the lab calculations for this marketing material.
You cannot drop 150lbs from the Model 3 motor because it doesn’t even weigh 150lbs.
You're missing the forest for the trees. Dropping 10 lbs per motor is HUGE. Dropping 30 is amazing. Whatever is dropped, it's significant. Pretend that it isn't all you want, but anyone doing production work knows how important this is.
I'm happy to compare apples to apples when we can do that, and if you want me to say I was wrong about the Tesla motor size I'm happy to say that I was just going by what was available on the internet and skipped the details. But I did so in service of a point which you still haven't actually engaged with beyond "Nu uh!".
> Dropping 10 lbs per motor is HUGE.
Auto makers could drop 10lbs, 100lbs or even more from every EV right now by choosing more expensive materials, more expensive manufacturing processes, or simply cutting back on amenities.
10lbs is not significant in the grand scheme of things. The real question is how much it costs, what are the tradeoffs, and how practical is it.
> But I did so in service of a point which you still haven't actually engaged with beyond "Nu uh!".
That’s not a fair take on what I’ve been posting at all. I said every little bit helps, but pointed out that motor sizes are already small.l
10 lbs per motor in an aircraft is huge. And the fact that they can do it WITHOUT having to use more expensive materials or manufacturing or amenities is the thing that is huge about it.
It's a fair take on your responses because talking about a SINGLE motor is missing the point. You're not engaging with the actual point that OP made, you're trying to dispute OP by engaging in your own point about what difference this would make in single-motor cars, instead of what difference it will make in general.
Range in EVs is impacted very little by weight
Exactly. I was very surprised to find out a fully loaded 40 ton electric truck only uses ~100kw / 100km ( https://www.youtube.com/@electrictrucker ) when my 2 ton Volvo averages 20-22kw/100km on road trips.
Weight impacts more than range.
That “2 ton” Volvo needs to be able to accommodate up to an extra ~1 ton of passengers and cargo which means it’s paying many of the weight penalties of a 3+ ton vehicle. Beyond that at highway speeds ~5x the range from a vehicle weighing ~19x as much suggests shows weight is a critical factor even if it isn’t the only factor.
Compare things at slower speeds and weight plays an increasing large role.
I wish more people on the road realized the extent to which weight reduction improves all aspects of the driving experience... it really does compound unlike any other change that you can make to a vehicle. IMO heavy vehicles are a scam and the antithesis of the direction we should be moving.
I agree with you however I believe weight and safety are in a complex relationship right now, which has nothing to do with performance and handling.
Unfortunately I feel much less safe in a Fiat 500 when a significant portion of cars in the road weigh nearly 3 tonnes and perhaps can't even see me. I suspect most people are in SUVs because they're the pragmatic trade off between safety and convenience, not because they were hoping for excellent performance.
Yup, it's an arms race to see who can buy the biggest vehicle so that they can see over the second biggest vehicle and survive a collision with it.
But small cars are only unsafe because of that discrepancy between the largest and smallest cars, and it's not just weight, but height difference. It's possible to survive crashes at very extreme speeds in very light cars if they are designed to work that way (see: F1 crash g-force). Not so much if you literally get run over.
The culture needs to change. A vehicle is not a living room. The driver's seat is not a sofa. You don't need a TV in the dashboard. You don't need 8 seats when 7 of them are unoccupied 90% of the time. You don't need to go into debt to buy a land yacht.
So yeah... you're right, but it's a bummer that we've arrived at this situation.
Classic prisoner's dilemma.
Everyone who can will naturally choose "defect" unless there's some sort of external coordination mechanism.
Not everyone, but far too many.
Your intuition is correct.
Americans’ Love Affair with Big Cars is Killing Them (https://www.economist.com/interactive/united-states/2024/08/...) - The Economist.
> In a crash, the fatality rate of the occupants of the heavy pickup truck is about half that of the compact car. But they are also far more dangerous to the fatality rate of people in other cars.
> The fatality rate is roughly seven times higher when colliding with a heavy pickup truck than with a compact car. As the weight of your car increases, the risk of killing others increases dramatically. For every life that the heaviest 1% of SUVs and trucks save, there are more than a dozen lives lost in other vehicles.
Unfortunately car safety is only evaluated in terms of safety for the occupants. Not safety of society.
I wonder if larger/heavy non-commercial vehicles were taxed at a very high rate, would more people choose Fiat 500 sized cars?
Maybe... I think it would definitely help. I think just driving a smaller car that puts you in control might cause a lot of people to switch. I know that when I've done the opposite; gone from a very performance oriented car to a random person's SUV, I've felt extremely unsafe comparatively in breaking, merging, changing lanes, parking, etc. etc. I think most people just have little experience to compare it to anymore.
I also think it's odd that people don't already choose other options w/o a tax in place, considering the price of a bigger vehicle is almost always just going to be higher because of materials and a bunch of other factors.
Tax SUVs out of existence.
A basic BMW 5 series is over 2 tonnes, with the top spec model tipping the scales at 2.5 tonnes. I mean I agree with the general sentiment but it's not just SUVs that need to go on a diet. Everything is getting heavier and heavier and heavier.
I see the same trend. My thoughts: 2 tonnes of shit sells for more than 1 tonne of shit. 650 HP entices a lot more people than 1,200kg. I usually have to dig to find the weight of the vehicle. It's a consumer education problem more than anything imo.
yeah, the tax should be based on car weight per passanger
That will just make the gigantic SUVs with 7 or more seats dominate even more.
car weight / min(number of seats, number of people in the family)
Ironically, they've been taxed into existence.
Not really. Small cars are still on sale in US. SUVs are popular in EU as well.
> I wish more people on the road realized the extent to which weight reduction improves all aspects of the driving experience
This is a blanket statement and completely untrue. Good driving experience is directly correlated to TRACTION, not just weight. And traction isn't just a function of weight - it also is affected by center of gravity, friction between the wheels and the road. Traction is what gives you the perception of being in control of the car.
I used to own two cars of the exact same model - one petrol and one diesel. The petrol is lighter in weight, about 100+ kgs lighter than the diesel variant. And the driving experience on that is slightly scary especially on roads with strong winds. In fact, it is so light that if you drive over tiny puddles or rumbles strips, the car will sway sideways. The diesel always feels more planted because it is front-heavy, thus adding more traction to the front wheels (both are FWDs). I always prefer the diesel for longer drives because of the heft and confidence it provides.
I get what you're saying, but tire technology has improved traction so greatly in the last decade that we can definitely take the slight loss in maximum theoretical traction for the massive benefits in other areas. There is also the question of what "maximum traction" is... what scenario are we talking about? Straight line acceleration from a dig or skidpad turning at a high speed? If we're turning at all then the momentum (which increases w/ mass) of the vehicle is what pulls it off course and causes the tires to break traction.
I also drive a FWD (a quite spicy one) and I break traction all the time, not because of weight, but because of torque. You can modulate torque, not weight. The biggest traction increases that I made on my FWD were when I put on sticky summer tires, the second was subtly changing front control arm geometry and bushings, and the third was adding stiffer engine mounts.
Agreed on getting tossed around in a light car though, not much can be done about that... other than making the roads better and lowering the center of gravity.
Absolutely and on top of that far lower pollution from tyre and brake dust, and less damaging to the road top surface.
Weight is not the only thing that matters though. You also need to consider center of gravity and wheel base. A YJ Jeep Wrangler and a Honda Fit both weigh around 2700 lbs and they even have similar wheel bases but the driving experience between those 2 is night and day. A Honda Fit can take a turn at speed without feeling like you're going to go flying. You'll feel like you're able to flip making a turn going 20 mph in a YJ.
This is why the first performance mod that most people put on their cars is an adjustable coil over suspension. Dropping the car down by an inch or 2 changes has just as much of an impact as shedding some weight.
Ironically, most people put lift kits on Jeeps but that also usually comes with widening the wheel base and putting on larger wheels/tires.
Lifting an off road vehicle isn't ironic at all, nearly every characteristic that makes a vehicle good on road makes it bad off road and vise versa.
Increased height makes for increased ground clearance and improved break over angle. Sway bars are another suspension component that's great for reducing body roll on road at speed, but reduces articulation and ground contact off road. Differential lockers also negatively impact turning radius, and cause tire chirp, wear, and oversteer under throttle on road, while increasing traction off road.
What's silly is daily driving an off road vehicle on road, especially if you never take it off road.
You are correct, ideally you would do both. My car is lowered on coilovers, I also have front and rear sway bars, but weight reduction is so much more than just handling.
I didn't realize that Jeep was so light... pretty nice actually, but yeah, that's just an application mismatch. People buy Jeeps that will never see even a dirt road in their lives. Then they get on a dirt road once or twice and say, "Look what it can do!" Sure... a rally car would be much better. In order for the Jeep to come into its own you need to be doing something that requires ground clearance... that's basically their singular purpose: rock crawling (which almost no one does).
> Ironically, most people put lift kits on Jeeps but that also usually comes with widening the wheel base and putting on larger wheels/tires.
That's not ironic. That's just caring more about the looks and you like that look. And looks > handling for that person
It's not at all about looks, it's about a different kind of handling, for off road, that's mutually exclusive with on road handling.
Yes, some people choose to emulate off road appearances, such as with fake bead locks and then only ever drive their vehicle on road. That doesn't discount the fact that there are a great many explicit choices you can make in designing and building a vehicle that sacrifice on road performance for off road performance.
I went from a 2021 Opel Mokka (4.2m long, 1350kg) to a 2024 Volvo EX30 (4.2m long, 2000kg).
It was an absolute shock the first time I braked in the Volvo, not to mention trying to take a corner.
Driving Volkswagen e-up for the first time was a very unique experience to me. My brain needed to adjust that a car can be that nimble and responsive due to its small size/weight and instant torque from the electric motor.
> In 2025, after a £12m investment, YASA opened the UK's first axial-flux super factory, in Oxfordshire.
It’s a little sad to me that fundamental innovations in electromechanical engineering like this get just a few million in investment, yet if this had been yet another derivative software startup with “AI” in the pitch, they’d probably have 10x+ or more investments being thrown at them.
Seems to me everyone wants to invest, instead, into something that can be "web scale" with low marginal cost, that is, natural monopolies. There is not enough anti-trust enforcement.
They should have named their company "YASAI" (pronounced as "Yes AI") and just watched the investments roll in ...
Factories take time to build. "Investors" want a get rich quick scheme.
Welcome to the UK and its innovation hostile environment. We don't have the US culture of throwing VC money at things and seeing what sticks.
This is less UK vs US, more hardware vs software.
But EVs are already heavy because of the battery. I suppose percentage-wise the motors don't make much of a difference (?)
The issue with this type of motor is that it is part of the unsprung weight since it is inside the wheel. This is probably why savings here matter a lot more (or at least in a very different way) than the battery weight.
Ok, now I understand why this motor is only used in supercars - installing four (or even only two - according to https://www.mercedes-benz.de/passengercars/technology/concep..., even the AMG GT-XX has "only" three of them) hub motors with twice the power of a Tesla Model 3 in any other car would be ridiculous. So, the actual challenge is to make this motor even smaller while keeping the same power to weight ratio, so it can also be used for regular cars? That is, if they want to build something for the mass market, not only for an exclusive clientele?
But why limit only to cars? Can this be used for motorcycles, e-bikes, electric buses, train wheels, e-unicycles, electric golf carts, etc?
There are probably a range of application where in-wheel makes perfect sense.
Donut Labs markets a whole suite of axial flux motors. Sized from scooters through to large trucks. But no public pricing.
I don't think their motors are axial flux, they're just large and narrow to fit inside wheels. Or at least all the images on their website depict radial flux designs.
And thrusters for boats as well, IIRC.
Motorcycles I could imagine.
Do e-bikes really need significantly more power than they have? They already run arguably dangerously fast for their application. Is efficiency not the primary target there?
e-bikes don't necessarily need more power but they could benefit from a smaller and lighter motor. If it becomes small enough to "disappear" in the pedal assembly for example, it would allow more design/parts commonality with normal bikes and fit more people's aesthetic criteria.
The lower weight would be definitely welcome, my ebike is comically heavy compared to a normal one and sometimes I have to carry it up flights of stairs (some German railway overpasses, grr).
Also in scooters it could fit in the wheel (since the wheel is tiny and has to spin quite quickly - no reduction gear needed vs a bike with 26-28" rims) allowing a simpler design and cost savings. But maybe in scooters they're already using in-wheel motors, I'm a bit ignorant there.
There are some advantages to hub motors in an e-bike, and if the motor and an appropriate gearing system could be made light enough the disadvantages would be reduced.
Oddly, a very large majority of current fully suspended e-bikes with rear cargo racks have those racks unsprung, which suggests that most e-bike manufacturers don’t actually care about the handling of anything other than their pure e-MTBs.
While more power may not make sense, less weight is an easy way to get more efficiency. And if you can keep the same power at a lower weight, that's a win.
The motor to battery weight ratio on e-bike is much more than for cars. Having a lighter motor would improve the efficiency.
Hmm. I am NOT an expert (though I ride and have owned 3 traditional motorcycles). IIUC, reducing unsprung weight is really crucial for handling -- which is why so-called "inverted" forks / front shock absorbers became basically the standard.
They don’t need this motor, but if it can be scaled down… at over 10kW/kg sustained, one could wish/hope to get 200W at 50g (disclaimer: I have no idea how this scales with size). Combine that with 1kg of a 600Wh/kg battery (https://news.ycombinator.com/item?id=45797452. Again, I have no idea how realistic that is), and you have a bicycle that’s only a little heavier than a non-electric one, but gives you a boost for 3 hours (more if you use it sparingly. If you’re cycling at leisure, 100W already is a lot of power)
For reference, an average commuter cyclist has a power output of about 200W, a world-class racer can do about 600W.
Ref: https://www.cyclinganalytics.com/blog/2018/06/how-does-your-...
Yes, all else equal, we want lighter motors in vehicles.
I'm always interested to hear about the latest in lighter and possibly more powerful and torque-y e-bike motors.
If engine can be produced cheaply, can it be limited "in software"? It's like saying people shouldn't use Rasberry Pi to blink an LED.
Yeah, you kind of shouldn't use a Raspberry Pi to blink an LED, though. Great "Hello World" project. But there are so many ways that are cheaper, lighter, smaller and more reliable (and don't require a lengthy boot-up).
Yeah, my first thought was racing EUC’s, lol….
End User Credentials ? Everyone Uses Cars ? Engineered Universal Conscience? (Since you seem to assume we all share your thoughts & context...)
I don’t see anything inside the article that says it’s designed to be inside the wheel. I’m not sure where they got that from.
From Wikipedia on Axial Flux Motors: >"Mercedes-Benz subsidiary YASA (Yokeless and Segmented Armature) makes AFMs that have powered various concept (Jaguar C-X75), prototype, and racing vehicles. It was also used in the Koenigsegg Regera, the Ferrari SF90 Stradale and S96GTB, Lamborghini Revuelto hybrid and the Lola-Drayson.[9] The company is investigating the potential for placing motors inside wheels, given that AFM's low mass does not excessively increase a vehicle's unsprung mass.[10] "
The fact that you CAN put it in the wheel doesn't mean it MUST to go in the wheel.
Yes but the wikipedia article is referencing YASA, the company in the featured article.
I think they misspoke when they said "in" the wheel, but supercars can have a separate motor for each wheel, and the closer they are to the wheel the better the torque as it's not also driving a longer shaft. The smaller the motor, the closer you can get.
I guess if you can make the motor and a suitable reduction box lighter than the equivalent bearing and driveshaft combination you could make the suspension arms mechanically simpler.
By using motors at each wheel you'd eliminate the need for a differential, saving a good 40-50kg or so. Of course, if you kept the drive shafts and put the motor and reduction box in the middle, you'd be able to use inboard brakes and save a lot of unsprung weight!
I wonder if that would be legal, or if there is a regulation about where you can put your brakes?
There are cars with inboard brakes, although not recently. From a packaging point of view putting them out at the wheel makes sense, since there's a lot of space you're not using otherwise.
It's hard to fit inboard brakes to front wheel drive cars because there's so little space but Citroën managed it with the 2CV and various derivatives, and the GS/GSA/Birotor family. They had an inline engine with a very compact gearbox behind, with the brake discs (drums, on very early 2CVs) right on the side of the gearbox.
You got lower unsprung weight and possibly more usefully the kingpin was aligned with the centre of the tyre, so when you steered the tyre turned "on the spot" rather than rotating through a curve.
Some old Jags and Alfas had inboard discs on the rear axle, which was of course rear wheel drive. They were a bit of a pain to get at.
I’ve generally assumed that brakes are in the wheel because they’re not all that massive, they get decent cooling airflow in the wheel, and they can produce enormous amounts of torque.
I get your skepticism and I know nothing about the field, but if the round thing in the press release picture isn’t designed to fit in a wheel, I’m confused. https://yasa.com/news/yasa-smashes-own-unofficial-power-dens...
Not necessarily, cf: https://lammotor.com/wp-content/uploads/2024/12/YASA-400R.jp...
From https://lammotor.com/yasa-axial-flux-motor/
the shape is due to the change to the motor layout: https://www.thedrive.com/news/why-axial-flux-motors-are-a-bi...
Well, Tesla also started with the higher end of the market. That's where people are willing to pay more.
I might be wrong, but I don’t think these motors are intended to be used inside the wheel. That would add a ton of additional requirements in terms of physical durability as well as constrain optimal torque and RPM of the motor design.
I believe the Aptera was originally going to have motors in the wheels... My understanding is the the first version will forego that, as there were challenges i guess, but i think they still to eventually do that.
Why would it have to be unsprung? They are not unsprung in the vehicle shown in the article.
> This is probably why savings here matter a lot more (or at least in a very different way) than the battery weight.
Wouldn't that make it worse or just ... different. Before this the unsprung weight wouldn't have had a motor in there and now it does. Increasing the unsprung weight doesn't seem a like a good thing.
What current mass production EVs use hub motors? It seems a lot more sensible to have the motors inboard, mounted to the chassis, and drive the wheel(s) with axle shafts. It seems in my searching this is how nearly all EVs are currently designed and produced.
YASA doesn't call it a hub motor specifically but that's one place where it helps to save as much weight as possible. And for the cars most likely to have 1000+HP weight matters too. A Tesla motor weighs 100-200lbs, so saving that much weight down to 28lbs on a supercar is highly desirable.
I think large drones will be another place where a downsized version of this motor will make a huge difference, assuming the power scales nicely with size.
Where does it say it’s inside the wheel? Not sure about that
He’s holding the motor in the picture. That format is in-wheel BLDC.
In-wheel application is possible, but it's important to understand that the pancake shape is only a consequence of the axial flux design and Yasa doesn't make motors in other "formats". Yasa motors shaped like this have been used in several supercars and all of them have been in-board on the axles, not in-wheel.
That format is the standard format for axial flux motors...
See also the Saab Emily GT project. Even with an older, heavier gen of these axial flux motors they found significant performance gains by controlling each wheel via its own motor.
https://electrek.co/2023/04/27/saab-engineers-develop-secret...
I didn't want to put the usability of the motor into question or go into a complete evaluation of advantages/disadvantages :) This was just an explanation that weight trimming the motor might be very much worth the effort - even if it somewhat "insignificant" compared with savings that are possible in battery weight.
I believe caring about unsprung weight only matters for handling not efficiency
It compounds. If you have a lighter more efficient motor you need a smaller battery for the same range, that combined weight loss means you meed lighter brakes etc etc, and because the car is now lighter you size of your motor you need is less.....
They claim, this compounding effect works out to basically double the effective weight saving from battery and motor.
ie if you start with saving 50kg on motor, and 50kg on battery, you end up saving 200kg over all. Still only about 10% of a typical electric car.
https://youtu.be/3qjB6GnhloY?si=yqlz7Evuyf5VaghO&t=446
> If you have a lighter more efficient motor you need a smaller battery for the same range
Nitpick: You can have a lighter motor, but you're never going to have a significantly more efficient motor because existing EV motor systems are already 95% efficient or better. The electric motor is an old and refined technology.
I'm not an expert - but the axial flux design while old is been largely ignored due to manufacturing problems that have now been overcome ( so most of the dev has been on the radial flux variety ).
And apparently axial flux motors have shorter magnetic flux paths which reduces losses.
ie the efficiency gain is due to the switch from radial to axial flux - not some incremental gain on radial flux.
Having said that the efficiency gains are relatively small - 1-2%.
However again there is a compounding effect, in that the reduction of loss of energy as heat, leads to requiring less cooling - and/or the motor is able to operate a full efficiency over a wider power output range ( as heating the copper increases the electrical resistance ).
https://www.stanfordmagnets.com/advantages-and-disadvantages...
What's a bit of a shame is they are no longer an independent company ( ie wholly owned owned by Mercedes ) - so that might mean we are less likely to see these motors combined with solid state batteries any time soon.
https://en.wikipedia.org/wiki/Tsiolkovsky_rocket_equation
Yea that's the thing right, the battery is so very much of the weight that optimizing the other parts are "meh" at this point. What is cool is that the 600Wh/kg solid state batteries seems like they are really finally here soon :) i.e removing 200-300kg from a car in one go will be a game changer.
No wonder electrics don't sell well in the US. People weigh more, you're basically saying that leaving grandma at home, is a "game changer".
>> removing 200-300kg from a car in one go will be a game changer
> No wonder electrics don't sell well in the US. People weigh more, you're basically saying that leaving grandma at home, is a "game changer".
Even in the US, your average grandma weighs less than 2-300kg :D
[This post to prevent ulterior posting of "yo mama" jokes]
Range being worse with a fully loaded car than with a lightly loaded car isn't exactly news, and not exactly limited to electric cars. I can clearly feel my old diesel struggling more when I'm driving 3 friends and with loads of heavy stuff in the back than when I'm alone. That makes the gas bill more expensive.
You probably know already, but ICE cars only convert about 20–30% of fuel energy into motion, while EVs are often +90% efficient. So when an EV has to work harder (extra battery weight or colder weather), you notice the drop in range more.
In an ICE, the same load is less visible because most energy gets wasted as heat. This is also why cold weather seems to affect EV range more.
> You probably know already, but ICE cars only convert about 20–30% of fuel energy into motion, while EVs are often +90% efficient. So when an EV has to work harder (extra battery weight or colder weather), you notice the drop in range more.
There's a kernel of truth here in that Otto engines suffer lower efficiency at part load, however I suspect the real reason is that gas car range is "good enough" and refilling is fast, so one doesn't tend to obsess about remaining range.
> This is also why cold weather seems to affect EV range more.
That's because a) some batteries suffer degraded performance at low temperature, and b) ICE cars use the plentiful waste heat for cabin heating whereas an EV needs a heat pump or even resistive heating of the cabin air.
> That's because a) some batteries suffer degraded performance at low temperature, and b) ICE cars use the plentiful waste heat for cabin heating whereas an EV needs a heat pump or even resistive heating of the cabin air.
You are making my point here actually. Combustion engines suffer from the exact same, but because they waste so much energy as heat already, less “extra” energy needs to be spent on that.
The unexpected benefit which I've noticed when switching from a small, light car to a heavier, medium EV car is that the latter doesn't drive/feel any worse when fully loaded. Makes the trips that much more pleasant.
That's true only if your very large "grandma" must at all cost sit on your batteries at all times.
If we could indeed leave "grandma" home, that would make things better.
And they don't sell well in the US because of oil lobbying and think tanks whose sole goal is to make you buy more oil.
Well, the world's most popular electric car brand (BYD) is also virtually banned in the US. That doesn't help with adoption.
True! If only grandma wouldn't insist on bringing 250kg of weapons and ammunition with her everywhere I'd get much better range in my EV, but alas this is the USA.
250kg grandma = ~20 small dogs
250kg weapons = ~20 small dogs
Instead of technological advancements of EV motors, we can immediately use existing pharmaceutical tech (Ozempic, GLP-1) to immediately deliver weight reduction to cars. However, this will be immediately offset by the increase in weight of weapons carried, thanks to Jevons Paradox.
Manufacturers may just keep the battery size and market the improved range instead? Smaller cars in urban and suburban environments have always had lots of benefits, but since many of them are collective in nature, it has largely fallen on tragedy of the commons, and we got larger cars with larger hoods instead.
Why not both? For a two-car family, having a good road-tripper and a light sporty car can work out pretty nicely.
Not true. Tesla themselves said the way they got the Model 3 to be so efficient was by optimising every single part exhaustively. It’s expensive at design stage but results in the most efficiency gains across the fleet - so worth it (especially something like the motors)
This is a negligible improvement to most things about an EV. Motors are already extremely power-dense.
There is a single exception, and it's a big one. Direct-drive, wheel-hub motors are not well-regarded right now, specifically because they increase unsprung weight (the part of the car more closely coupled to the road surface than the passenger) and this impacts handling substantially. So instead we backport a bunch of the mechanical infrastructure that transfers power from a traditional ICE engine to the four wheels. We're paying that bill already, on almost all production EVs. Quadruple the power density and simple, 1-moving-part wheel hub motors look like a lot better case versus central driveshafts and mechanical linkages.
Tesla Model Y's battery is 771 kg. The motor in Model Y weights about 45 kg, about three times as much as the motor in the article. By reducing dual motor configuration weight from 90 kg to 28 kg, we reduce total powertrain weight by 7%.
The new motor is also much more than double the power output of the Model Y motor, so the second motor and its wiring could be eliminated completely.
No, because that second motor gives you AWD. Sure that's a feature you could go without...
But torque and power were never the limiting factor for an EV. You would only benefit on a track, and if you're taking a model Y there...
You’d need to add back in an all wheel drive powertrain. A typical drive shaft is 20 to 50 pounds (9 to 23 kilograms)
The motor is high torque, so I’d expect the drive shaft to be on the heavier end of that.
I’m not including the other power train components, but it’s easy to imagine it all adding to more than the weight of a second engine + wiring.
Also, having one more complicated power train is probably less efficient than two simpler ones, which implies a bigger battery.
And shouldn’t it be possible to make the battery smaller with a more efficient motor?
It is not indicated anywhere that this particular motor is more efficient than older ones in terms of the electric force conversion.
This new motor is more powerful, that's it.
Nothing was said about cooling or voltage requirements. The latter is important because higher voltage is more dangerous to work with or be near.
Ah ok, that makes sense
The battery could be made smaller by whatever amount is needed to carry the marginal motor weight the advertised distance.
Batteries are the bottleneck.
Even if motors were literally weightless and mass-less, EVs would weigh more than ICE cars.
It's like making a more efficient CPU for your phone when all the power is eaten up by the cell-modem, screen and RAM. People wonder where the practical battery life gains are and theyre miniscule in practice
> According to YASA, this is achieved without using exotic or expensive materials, so the design could actually be scalable once the demand kicks in.
That is ever more special
I'm more excited about light electric vehicles. (Bikes, tuk-tuks, what-have-you).
...with 1,000 horsepower. =:-)
In fairness, ICE engines have been able to provide too much horsepower for those use cases for a long time.
Cutting the motor weight probably matters more for smaller vehicles than bigger ones though.
That wasn't so much a criticism of the electric motor, which it sounds like they can scale down, as the Neanderthal part of my brain lighting up. Mongo like power to weight ratio.
Only the absolute weight of a motor counts, because consumers of passenger vehicles do not require 1000 hp.
How far does YASA's tech allow the motor weight to scale down, for applications where you don't need the power?
Can you make it 2.8 pounds instead of 28, if all you need is 100 hp? Likely not.
Better for robotics as well.
I don't see the weight reduction being very significant.
If we take a Tesla model 3, I believe it weighs 1611kg, and the motor shows up at 80kg if you google it (no idea if this is correct). This YASA motor by comparison weighs 14kg. So, this would drop the vehicle weight by 66kg out of 1611, so that's a 4% saving.
I assume that means it would be more like an 8% savings on the dual motor variants? At what point does it become significant?
This motor is well more than twice as powerful as the Model 3 motor, so it could eliminate the entire weight of the second motor in the higher performance models. That’s 146kg, the weight of two adults, an 11% reduction.
> Could lead to significant efficiency gains for EV's
Not really. EV's are very heavy from non-motor weight. A Model Y weighs ~4300 lbs. A motor that is 75 lbs lighter is a 1.7% savings. That's not nothing, but I wouldn't say "significant". You can do better by swapping for fancy wheels or eliminating some of the glass roof.
And really this is true up and down the electric vehicle world. Weight-sensitive applications are always going to be completely dominated by battery weight. Making the motor smaller just isn't going to move the needle.
Basically this is good tech without an application, which is why it's having to tell itself with links like this.
It’s great anywhere you want more power but are limited by space and/or weight for performance reasons. Aerospace, e-bikes, electric race vehicles, electric motorcycles.
But yeah, EVs seem weird except for racing reasons perhaps.
What I can’t figure out is how they dissipate the heat - double digits kw per kg is crazy.
The first step to dealing with heat at high kw, is to not generate the heat you have to dissipate in the first place. Which means chasing smaller and smaller efficiency gains, because that reduces heat generated.
The more of the energy going into moving the vehicle, the less heat the motor has to handle.
Sure, but at 50kw/kg at 99% efficiency is still 500w/kg, which is cray cray. Like ‘glowing red hot shortly’ type of crazy with just passive cooling.
And there is no way this is 99% efficient.
So my question still applies. Even 98% is 1kw/kg, or 1kj/sec. or around 3C rise per second assuming the mass is 100% nice clean copper (it isn’t). Everything else will be worse.
Not even counting increasing losses with temperature, it will be a molten puddle pretty quick at that rate without some major active cooling.
I was waiting to see in the comments EXACTLY this question: There is no way to dump this heat. 1000hp? Yeah, maybe for a few seconds, even with oil coolant pumping through there. Then how to dump the heat from the oil. And further thinking, if they ever get this to be a hub motor, how in the world are they going to pump coolant through 2-4 hub motors and then to a radiator that can dump that rate of heat rise, especially since oil is a lousy coolant (relatively speaking).
Again, no, because the motor needs to be powered and the battery is vastly larger than the motor already in any of those applications. Even in RC planes, which fly for 5-6 minutes at a time, the battery is 5x or more the weight of the motor, wiring and controller logic.
saving 30 kg of weight on a 2000 - 2500 kg car won't lead to "significant efficiency gains"
The Ferrari 296 GTB weighs about 1500kg and the sports version 1300kg. For the cars YASA produces motors for it's much easier to increase the power to weight ratio by reducing weight than increasing power. I imagine an important design point for all of its components is to reduce weight.
I agree insofar as the motor is not a Big Ticket Item, opposed to ICE cars where the engine block is going to be 10% or more.
Tesla (I know) claimed a 30kg (?) weight loss on their Cybertruck (I know) just from moving their 12V systems to 48V, allowing for lighter cables at lower currents. Not all such potential is untapped, and my hunch is that there is more to be had with structural battery integration, battery cooling, and high voltage wiring.
If you put several small motors on each wheel you might get some extra weight gains in the form of less transmission needed. Cables weight less than metal structural bars. But yes you are not going to be 500kg lighter.
Depends on your definition if significance, but I think they do. Every kg of useless weight you do carry, lowers your range. But sure, on its own it is not a magic game changer for heavy electric cars.
For light weight vehicles on the other hand, it might be.
Weight reductions on an electric car are self-reinforcing. If you reduce the weight of a component, the battery can become (slightly) smaller, which again reduces weight. At a certain amount of reduction this will allow you to make the whole structure lighter, which will again allow for a smaller battery.
So yeah, weight reduction on EVs is great.
Also not considered is that the announcement is for 740bhp motor. The Tesla model 3 has a vehicle output of about 400 hp. I’m not sure of all the design specs, but it seems clear to me that a smaller version of these motors could suffice to drive a 3 equivalent vehicle at 1/2 the output and still be more than sufficient. So let’s say maybe 15lbs each, vs current equivalent 70lbs each. It’s not major total weight impact, but with battery advancements it will compound.
I think people are overlooking that the announcement is for a performance motor meant for the performance market at the moment because that is what the backers of YASA are most interested in because it has the highest margins and prestige. Also not mentioned is the efficiency from the simpler production line.
My impression from what I know is we are looking at an impact equivalent to direct injection engines; not revolutionary, but a major advancement of one component that has significant and consequential effects.
The e-motor is often “overpowered” in EVs (compared to ICEs) to make regenerative braking efficient, i.e. capture meaningful energy from braking.
And because almost everyone is a sucker for the "Stomp on the pedal and it goes fast" marketing strategy and demonstration.
That's why a modern Camry makes almost 200 HP
> This is awesome. Lighter motors also make electric flight more viable
The next innovation we need is Aerial refueling[1] for electric planes. High density swappable batteries and high altitude wind/solar plants that can swap batteries mid air. Perhaps some billionaire will develop a large fleet of these to service all flights! If no western billionaires, we just have to wait for China to develop this tech.
[1]https://en.wikipedia.org/wiki/Aerial_refueling
A sufficiently compact electric motor enables mounting it in the nose-wheel of commercial aircraft, allowing it to be driven around like a golf cart. This means the plane can taxi without the use of its engines, just the power from the APU. [1]
Also planes would not have to wait for a tug to pull back from the gate, which improves turnaround times for the airline.
[1] https://www.wheeltug.com/
You could also spin up the landing gear wheels prior to landing to massively reduce the amount of rubber transferred from tire to runway on touchdown. Rarely done today because of the weight and complexity of adding motors, but letting the ground spin up the wheel is pretty expensive both for tire wear and runway maintenance
Apologies for the turbulence, we're just flying through a thunderstorm to top up the batteries
Or laser power beaming from a satellite, or a ground station.
Not very feasible, but an option that has been thought through.
I guess there’s a system that’s gated to track dependent technologies, to track improvements and what they’ll enable.
Surely it would be easier to recharge rather than swap batteries? I wonder if in the future war will be like a turn based strategy game as everyone wait for drones to recharge before making a move.
Mid-air: yes. A boom with a charging cable or even beamed energy would be much easier.
On the ground: swapping batteries is faster, and batteries are cheaper than planes or drones. You want the expensive part back in the air as soon as possible so you don't need as many of them. On the whole this probably also simplifies logistics: in civilian aviation airport space is limited, in wartime it's easier to transport one hundred drones and two hundred battery packs to the frontline than to transport two hundred drones
That's a future thought when it comes to electric aircraft - remote/emergency refuelling. I know they have tested lasers, and even sent a megawatt in 30 seconds over a distance of a few miles, though current convention of the laser back into usable power is around 50% efficiency. All gets down to a needed leap in electricity production and wished the World would get together on fusion reactors and knock it out the park over a mad race to be the first and lock down patents.
A typical regional aircraft needs about 3MW of power to keep in cruise, and has about 50 square metre area, so 60kW per square metre. Even with 50% efficiency you're talking over 100kW/m^2
A laser over 10W has safety implications. This is 50,000 lasers all shining on the same plane.
Given your collectors are only going to be say 50% efficient, you're likely going to dumping enough wasted energy into the wings to melt the aircraft - not sure what dumping 3MW of heat energy into a plane would do over an hour, but I suspect it would stat to melt in a few seconds if you're lucky (otherwise your passengers would start getting very toasty)
At 3MW for an hour that's not a great amount of electricity that's needed - at 10c/kWh it's $300 an hour. You don't need fancy things like fusion to generate that. In the UK alone Solar is currently (in November) generating 600 times that - plus domestic installations.
I don't see it working like that in Ukraine...
Difficulty for swapping batteries too - how to differentiate between strategic bombings and a refueling accident.
The other aspect is that a smaller motor with the same power generally has higher efficiency, by necessity, since it has less heat dissipation. So higher power and higher efficiency and lower size/weight all go together. It’s a great synergy.
Is it always true that a smaller motor with the same power has less heat dissipation? It doesn't seem all that obvious to me.
It will probably lead to cars that fail sooner and are cheaper to build
A link to the press release https://yasa.com/news/yasa-smashes-own-unofficial-power-dens...
> 59kW/kg
At this point why don't we get rid of the k prefix and write 59W/g?
Edit:
I was half joking, but various answers mention kW being standard for motors, kg being the SI unit for mass etc. All true, but as used here in a combined unit, which means "power density" it still would make sense IMO. It's not like the "59" tells you that it's a strong motor and hence you want kW to compare it to other motors. You can't, it's just a ratio (power to weigth). W/g just reads much nicer in my head. Or we could come up with a name, like for other units. Let's call it "fainpul" (short fp) for example :)
59 fp is a new record for electric motors!
Because kg is the fundamental unit of mass and kW is typically used for electric motors.
Same reason you wouldn't use m²/s³ even though that's also technically correct.
If "kg" is the fundamental unit of mass, then honestly, why isn't a gram referred to as a "millikilogram"?
Reminds me of the protest in the Shenanigans and Gimmicks part of this project: https://gre-v-el.github.io/Dimensional-Calculator/
Amusingly, given the other thread in here with people sniping each other over the metric system, I'm obliged to point out that kg, not g, is the fundamental unit of mass in SI, because even metric can't get away without some silliness.
It gives a sense of the functional size required.
Could the motor in question be shrunk down to 1kg, producing 59kW? Probably.
Could it be shrunk down to 1g? No.
kg is the SI unit for mass, I think that would be why
Comparison with other motors
Much better you should post it and somebody mark the banner ridden one for deletion.
'Supercarblondie' manages to hit everything I dislike about automotive marketing online all at once.
Yeah wasnt blondie the name of a dog belonging to a certain historical figure?
Ha! I didn't know that. This blondie is definitely, definitely the more, um, traditional(?, oof) genus and species of American 'blondie' (no offense to blondes, I promise, as my disdain is in the direction of protection of blondes rather than broad criticism)
A much better link .. and probably not to late to change it via [edit] on submission in your view..
The YASA link is primary, links to test data and back story, and has more detail substance and authority.
This discussion is all about vehicles with large batteries, but how about hybrids? With light enough and efficient enough motors, all kinds of designs might become practical:
- Toyota-style hybrid drives could be a lot lighter, and they don’t need large batteries.
- e-bikes with tiny batteries?
- Hybrid aircraft? What if there was a battery large enough for takeoff and landing, a small motor (or pair for redundancy) for cruising and to recharge the battery, and motors and fans or propellers wherever is best from an aerodynamic perspective.
- Power tools.
My first thought too.
While I see Toyota-style hybrids as designed for efficiency, there's also the performance hybrids like the new Porsche 911 T-hybrid where an electric motor spins up the turbocharger to eliminate lag while another integrated into the gearbox adds power. There is no "EV mode" so it doesn't need a large battery.
Arguably the most important characteristic of a sports car is light weight, so lighter motors would be immediately useful there.
The size of this motor is moderately interesting, but the power density doesn't really matter for most of the things you just mentioned. Almost every one of them is limited by the amount of batteries you can put in for both weight and power output reasons.
There's indeed a huge number of applications where lower weight electric motors could be useful.
The questions I have mostly centre around how much precision of power delivery it has - it is an all or nothing proposition, can it deliver 0.1% smoothly for real world use, and what is the MTBF / duty cycle / failure mode? I would imagine the last thing anyone would want is a locked wheel, or only one wheel delivering that much power. I know this is unlikely, but as someone with a 22-year-old ICE vehicle I do tend to take the long view on these things and want to know how they will fail as much as how they work. Same applies to the Tesla motors - is there much information on failure modes publicly available?
The new YASA axial flux motor weighs just 28 pounds, or about the same as a small dog.
But how many footballs a small dog weighs?
Not sure about that, but if you ask me, a really small dog only weighs up to 7 pounds - or otherwise said, this motor weight as much as four fat Chihuahuas ( https://en.wikipedia.org/wiki/Chihuahua_(dog_breed) )
New performance ratio: horsepower:dogweight.
> But how many footballs a small dog weighs?
Which kind of football: the British or the US-American one? :-)
Australian rules.
Lol. I was confused by it also. I have no idea how much is 28 pounds, and I could imagine how a small dog can be anything from 1 kg to 10 kg. It happens that the motor weight is ~13kg, but I'm still not sure that 13kg dog counts as "small".
123.5 cubic centi-litres
Not sure about footballs but 28 pounds is about the weight of a child, a bag of rice, or a dumbbell. Hope that helps!
How much rice do you buy at a time?!
Asian grocery stores carry 25 pound bags of rice and we use about 2 each year. If you eat rice regularly, it’s the way to go.
American football or international futbol? If American, it's twelfteen furlongs.
Ok so whats the catch with the technology? Its more powerful, smaller, all readily available materials. Some kind of strange shape, longevity challenge? Difficult to make so costs are tough to bring down?
Just noticed that they are owned by mercedes benz- they will kill it accidentally. Corporate wont be able to roll it out. They will try and capture all the value and kill its potential
Axial flux motors are difficult and expensive to make.
Motors need to be made of laminated steel sheets to reduce parasitic eddy currents. The laminations need to be thin in the direction of the direction of the flux. For radial flux motors you just punch out a shape and stack a bunch of sheets up. For axial flux you have to wind a strip: https://15658757.s21i.faiusr.com/2/ABUIABACGAAgmviFqAYozvPw-...
Each layer of that strip has a different cut in it, so its much more complicated to make. The shape and manufacturing method typically impacts efficiency; YASA avoids that by spending more money. Efficiency is an unavoidable requirement of high power density- heat is the limiting factor, and going from 98% to 96% efficient means double the heat.
The mechanical demands on the motor are also much higher- radial flux is balanced since the magnetic force pulls the rotor from opposite sides. Axial flux motors are usually one-sided, so the magnets are trying to pull the rotor and stator together with incredible force. That also makes vibrations worse. Extremely strong, expensive bearings are required to handle it. With permanent magnet rotors you need a jig to lower the rotor into place; they can't be assembled by hand. That also makes maintenance more difficult and expensive.
>> Each layer of that strip has a different cut in it, so its much more complicated to make.
You can roll a spool of that material and then machine the shape out of it. I've seen this done for axial flux motors. There are other approaches as well, and the cost differences get even smaller if you throw automation at the production process. I used to believe axial flux motors were one of those oddities that won't win in the end, but now that I work with them I'm not so sure. They are at least competitive with radial flux machines.
Can you (or anyone) explain where the power density improvement comes from with axial flux? When I work through the first-order math it seems like it should come out the same as radial flux. Is it just that the geometry allows better cooling from the coils? Or the use of grain oriented steel?
I was wondering where the seam is supposed to be in that picture and then it turns there is no seam. It's just one continuous roll.
https://www.youtube.com/watch?v=6ZVQWgk6tRc
It's easy to forget that most of the weight in an electric car is the battery. It's ICE cars where a lot of the weight is in the motor.
That being said, could this be adapted so that a 2.8lb motor produces 100 hp? That would allow putting a small motor in each wheel, thus completely eliminating axels, driveshafts, and allow recapturing the space they used to occupy. It also wouldn't significantly impact unsprung weight.
First, no, it won't scale like that.
Second, don't forget that you're trading one complexity for another. Eliminate a drive shaft and you still have to get power to the wheel somehow, which means now you're running high power electrical cable in a very dynamic environment with exposure to the elements. On top of that, you need to cool the electric motor, so you're probably running some kind of fluid out to it. Not that it isn't a solvable problem, but it probably doesn't reduce the weight much, if at all, when the system is all added up. You'll find that while you eliminate an axle, you still need to mechanically connect the two wheels together (look at the rear subframe on an FWD car) for strength, which also reduces the weight loss. Then the steering on the front... etc.
Until a more significant change than this motor (where maybe a 2.8lb motor could produce 100hp without needing active cooling), we're better off with "inboard" motors still.
Is it really easy to forget?
People used to say they would only get a Tesla if it was offered with a manual transmission.
It's easy to laugh at, but there are still many people who haven't shifted, in their mind, to the differences.
Even after driving EVs for over a decade, I still need to shift. My habit is to turn the car off and close the garage inside the car. My new EV only controls the garage if it's on, so I had to get used to closing the garage with the car on. There's still a part of my brain that screams "but carbon monoxide" every time I do it.
Really easy, I've just forgotten again.
I'm curious as to the efficiency of the motor (basically, how much of the input electric power is converted to motive power).
If it isn't very good, then it might be excellent for drag races, but maybe not so many others.
Also, any power that doesn't turn into torque, is likely to be expressed as heat.
It would almost have to be very efficient -- they're saying it can do something like 500HP continuous, and it doesn't have enormous fins all over it for cooling.
Looking at the picture, it looks like there may be a liquid input (cooling). Even a very efficient motor is going to need cooling (and lubricant).
Exactly my thought as well. You can have all the horsepower you want but if it doesn't convert the electricity efficiently, it's not going to be useful for normal consumer cars.
Outperformance metric is basically power density. The model described is some 13 kg and delivers 750 kW peak, 350+ kW sustained.
(That's 28 pounds, 1000 hp peak, 470+ hp sustained.)
The 40% improvement is actually 36% and is versus the previous model of the same company.
Peak power is a number that can be manipulated. You just dump short circuit current into a winding. Even if that peak lasts for 1 microsecond, you can "claim" eye-watering horsepower numbers.
I wonder if we defined peak as sustained peak over 100 milliseconds, or some more meaningful number, what that would do to the claims. You aren't really generating meaningful torque over 1 microsecond.
I sort of wonder how well these things can be scaled down.
Wheel hub motors are obviously bad, for harshness reasons, but if you could have a motor like this weighing 1-2 kg, and put one on each wheel, that'd be okay.
Power-wise this would be okay if things are linear. 26 kW per wheel sustained power output is more than enough for a light car. The question is what torque a scaled-down machine can be expected to have.
I'm wondering if it would make sense to integrate the rim, motor and wheel bearing into a single assembly to save weight and cost. That combined with the weight and packaging benefits of not having half shafts and differentials might make it worth it. Plus there can be additional benefits, like the extra maneuverability that ZF Easy Turn and Hyundai's e-Corner have demonstrated.
30kW sustained/60 kW per wheel peak power is easily enough even for large passenger vehicles. Sustained could take 3 ton vehicle up a 10% grade at 120 km/h.
Thanks. Do you also happen to know the power density of the motors in the average EV car? Because the article uses "nr of Tesla Model 3" as a unit, which is meaningless without further details about it power density.
The power density doesn't really matter unless you want to put the motor in the wheel. You need to keep the unsprung mass low.
Basically all EVs have small and light motors compared to ICEs or compared to the battery. Shaving off ten pounds there is irrelevant.
> That's 28 pounds
or about the same as a small dog
There was a video on this motor recently: https://www.youtube.com/watch?v=r4OdH0ibOBk made by a phd in the field
That’s an excellent video!
Previous discussion: https://news.ycombinator.com/item?id=45675020
It is great that Mercedes-Benz now owns a highly performant electric engine. But is this just an impressive lab breakthrough, or can it work in the real world for their cars? Which means enduring from freezing to high temps, hours of sustained driving, and years of that (or equivalent endurance testing).
It's not a lab model (according to the article), but it's likely aimed at performance cars. For consumer cars, 150 KW / 200 HP is enough and efficiency is more important than weight.
Of course, when consumer car efficiency increases, they won't necessarily get higher ranges because the manufacturers will instead try to downsize the battery.
A similar company is based in Munich: https://www.deepdrive.tech/ They have cool testing facilities applying CI/CD practices to testing hardware!
> YASA, which is a wholly owned subsidiary of Mercedes-Benz, already produces motors that power some of the world’s fastest and most expensive cars.
Never underestimate the swabians.
> According to YASA, this is achieved without using exotic or expensive materials, so the design could actually be scalable once the demand kicks in.
So, no rare-earth magnets? And it will be cheaper than existing motors?
You sent me down a rabbit hole.
I have no idea, but:
I searched axial flow motor in wikipedia, and the last link is:
https://newatlas.com/technology/conifer-iron-magnet-electric...
So maybe?
Rare-earth magnets do not fall under “exotic”.
They are expensive.
Especially when China refuses to export them…
They’ll happily export them in car form, but the US can’t have nice things anymore.
If used in power generation, would they open new options?
e.g. high RPM, or high torque options over existing generators?
I had the same question - would this make, I dunno, super efficient wind turbines?
This was already on HN a short while ago:
https://news.ycombinator.com/item?id=45675020
12 days ago | 59 comments: https://news.ycombinator.com/item?id=45675020
> It can also sustain between 350 and 400 kilowatts (469–536 horsepower) continuously, meaning it’s not just built for short bursts, as it can deliver massive power all day long.
On what battery?
Pretty much any modern car battery out there. Many of those allow 350 kW charging, discharging that quickly is even easier.
28 pounds - that's gigantic compared to this https://now.tufts.edu/2011/09/05/worlds-smallest-electric-mo...
> "There has been significant progress in the construction of molecular motors powered by light and by chemical reactions, but this is the first time that electrically-driven molecular motors have been demonstrated, despite a few theoretical proposals," says Sykes. "We have been able to show that you can provide electricity to a single molecule and get it to do something that is not just random."
"something that is not just random" ==> Probably a long way away from something in production. I wouldn't hold off on any urgent transportation needs waiting on this tech.
That's wild! Tiny motors packing that much power? Sign me up for the future of racing!
Axial flux motors are so next level. Very little power needed per rpm. I’ve built a few tiny ones for FPV and they are a joy to work with. I’ll die a happy man if I never have to coil again.
So can I jet ski from NY to London in a few hours?
Just stick four on a car with fans on and there's your flying car. Not much range though probably.
Current motors seem to suffice just fine:
https://youtu.be/ysE8FMhAPH0
the first thing I thought was building a robot dog with these, they probably already built an evangelion with these they aren't showing us
How much torque can it generate?
Their website claims "4 X more torque and double the power densities of current technologies".
A bit handwavy, but given the inherent torque advantage of electric, I doubt torque is an issue. If anything, a lot of EVs would probably do better with a touch less torque.
Source: https://yasa.com/technology/
It's cool, but I think deploying motors without rare earth materials will be more impactful. The Nissan Ariya was ill-fated for other reasons, but it had a EESM motor that is easier to cool, more efficient at speed, and cheaper. That's where motor tech is headed. Power density just isn't terribly important in current applications, at least not past current sota.
It's very hard to find any supplier who will sell an axial flux motor to the public.
I see lots of press from Yasa & Donut motors, but afaik no public pricing & relationships with select partners only.
I wonder if this tech is already being used in F1, or if it makes sense to do so. The weight savings alone could easily make a championship winner.
EV motors are not that heavy. Ok it is 1/4 of a tesla motor but would that make much of a difference compared to the rest of the car since the weight of an EV motor is in single % of the entire weight.
Sounds like it could be more important for drones?
It is important if you want to put the motor in the wheelhub. Too much unsprung mass kills vehicle dynamics.
Drone motors are aircooled though, so I think you actually want the radial configuration.
Saving up even few % of weight while not compromising on comfort/safety is a holy grail for any decent car manufacturer.
Not sure why the negatives in this thread (maybe too many folks hold TSLA stock?), this is properly awesome (r)evolution.
I do not know why people still think Tesla is a unique company. They are a regular car company now. Nothing more, nothing less. Yes, they disrupted the market and the reward is a standalone, viable car company. That is a huge achievement. But their disruption and uniqueness is gone. The rest of the car industry woke up and all are producing many more EV variants and EV cars in total.
How the heck are they dealing with the heat produced? Water cooling?
Oil cooling. Besides this is a peak power value, so thermal constraints don't matter. Continous power is given around 350-400 kW.
(Sources: https://yasa.com/news/yasa-smashes-own-unofficial-power-dens... and https://yasa.com/technology/)
I wonder whether it is about the same as a small dog
Great! When can I order one packaged in the form of a drop-in limited-slip NA MX5 differential?
Tesla should buy Mercedes, they'd make a good team together.
Surely there is still some merit in having competition in the market place?
Tesla is getting out of the car business
Mercedes should buy Tesla you mean.
Tesla, Inc. (TSLA) – ~ US$1.50 trillion
Mercedes‑Benz Group AG (MBG.DE) – ~ US$62 billion
MBG AG:
Revenue - €153.2 billion (2023)
Production output - 2,491,600
--
Tesla:
Production output - 1,773,443 vehicles (2024)
Revenue - US$97.7 billion (2024)
--
Maybe Tesla is just hillariously overvalued and MBG AG can afford them once the hype bubble implodes.
when the hype bubble implodes.. Tesla doesn't exist anymore. None of their perceived future value is based on automobiles.
Maybe that's why they have never built out a proper service facility network.
One of my fundamental criticisms of Elon musk performance as a CEO. The vast stock market price and valuation should enable these sorts of transactions.
It would enable Tesla to diversify operations move into applying its technology on a mass-market basis to hybrids without "damaging" the "purity" of the Tesla brand.
It would enable more marques to target specific economic bands, international markets, etc.
But no we basically have a car company that makes two cars.
Elon Musk has completely lost interest in being CEO of a car company. Tesla is a whatever's-on-his-mind-today company.
Cars are probably fine without that engine. But for drones and robot actuators it should be a huge boon.
I am heavy motors guy, and this is my EV. She weighs one hundred fifty tons and drives four custom-tooled motors at one thousand horsepower per wheel.
It costs 10,000 Wh to power this car.. for 12 seconds.
Can we build an electric scooter with it?
Can I get one for my bicycle
Yet Another Sale Abroad. Not a criticism of the YASA team. It’s hard to scale a company in the UK and foreign investment is a good thing in general. But still frustrating that the UK was unable to offer the kind of investment that Mercedes could to keep a company British.
We're a country who even sold our water to the highest international bidder ...
What would make you think we wouldn't sell our tech crown jewels also? (throwing in our grandparents and children to sweeten the deal).
Everything but the Metric System: “The new YASA axial flux motor weighs just 28 pounds, or about the same as a small dog.” :)
I wonder if Americans don't have a mental image for measurement units so that they alway use some physical object as a reference. Sure, its useful to use a common object as a reference but I don't see that much often in other places.
Most people usually understand what it means something to be 20 meters, 5kg or 2 liters intuitively. Like, when I hear that something is 60m tall I intuitively think if it as 20 story apartment building and don't benefit from the extra info about how this is like 18 elephants stacked on each other.
I guess you're in the minority here. In Germany, everything Remotely large will be measured in football fields or "Saarlands".
I'm also European and don't get these olympic swimming pool or whatever comparisons. I'd have to look up how many m3 of water they contain or what's the length/depth in meters are to make sense of it.
Newspapers in my country don't make these silly comparisons.
But yeah, to be fair, when hearing about Starship I had to look up our TV tower height to identify whether Starship is taller or not. It disappointed me that it's not.
Yeah, height is easier to grasp when correlating in terms of x story apartment buildings.
Don't forget to mention the inofficial units for fluid volumes being "Badewannen" and "Schubkarren".
Can’t forget the Olympic sized swimming pools!
Whats the speed of light in football field terms?
Approximately 7 708 937 142 soccer fields per half time.
Are we including stoppage time?
Yes I'm always a bit dumbfounded by this behavior as well. They always use weird stuff and I never have the intuition of the actual size, especially since the definition can vary depending on context.
In this case, what is actually considered to be a small dog? To me it would be something that is close to the size of a cat but since it's about 13kg, it can't be that small, so that's more like a medium dog (I'm not certain, but I have a feeling that if you lay out things statistically this is what you would end up with). On the other hand, 13kg is very easy to get, that's just 13 liters of water, and it's quite easy to make a mental image for both volume and weight "feeling" that way.
American units feel so impressive and random, it is the reason they always add those weird comparisons but often they make it even worse.
What's the difference between 18 elephants stacked versus a building with 20 stories? They are just different analogies.
Which is strange, since one of their measurement units is literally based on a body part.
Americans do not do metric. Americans can’t even balance a checkbook. Hence the small dog reference for mental “clarity”. We’re dumb. Just look at the news…
I don't think it's fair to insult all US citizens because of your personal shortcomings.
I think it may be fair? This guy[1] explains how surplus of corporate profits are a mirror image of household/govt debt. Which is a direct transfer of wealth from everyone to the super-super-rich (not the 1%, but the 0.1 - 0.01%)
[1] The chart below shows how this works. The blue line at the top shows the “surplus” of corporations: corporate income minus expenses and net investment. We know this as corporate “free cash flow.” The red line shows combined “surplus” of other sectors: government, households, and foreign trading partners – in excess of their consumption and net investment. It’s negative, so in aggregate, they’re running a deficit. That deficit is the mirror image of the corporate surplus. This isn’t an accident. It’s just accounting (I’ve excluded a few tiny items for clarity): https://www.hussmanfunds.com/comment/mc251028/
Statistics my man, statistics. I’m not saying there aren’t smart Americans that can grok a 10kg bag, but that the vast majority can not.
I'm Canadian. I don't know what 10kg feels like until I convert it to pounds.
Do you not have personal experience with people under 40 in America? I would bet $20 over 95% of them don't know how to balance a check book.
95% of them can’t turn a block of flint into a spearhead either. Without skills like these, how will the younger generation hunt mammoths?
Who still uses a checkbook?
And with your bank balance instantly available on the computer in your pocket, and transactions posted in near-real-time, why would you need to worry about balancing it?
Why are you going on about "balancing a check book?"
I'm in my 40s. Never did it, never going to.
I would bet $20 over 95% of them have never needed to balance a check book, and probably never will.
No, Americans are numerically illiterate.
Which is why all the dumbest Americans insist that "Why didn't they teach us how to balance a check book?", while, well, they were taught that, and every single check book comes with clear and simple instructions for its use
They were also taught how to calculate loan details and the extreme power of how interest grows, but they were too busy crying "Oh this is lame, when am I ever going to use this?"
There's a cult of proud ignorance in the US. People will brag about being uneducated, illiterate, or unable to follow simple instructions.
Sure but don't they have a mental image for 80 feet for example? Why articles will almost always include something like "that like 50 chairs put next to each other" when length is mentioned.
If you were to say 100 yards, we could. That’s a football field (American football played with your… hands).
Because people in the south don’t even know the imperial system… it’s bad. They say things like “Take the road there yonder and when you see the white church, turn right, go a ways until you get to the dirt road…”
Anything outside of what they have with them, they don’t have a clue or can’t imagine it accurately. Small dog reference, there’s millions of Americans with a small dog so most just looked to their pooch when this came up. Same as if you were to say something like 50 cars. They would look outside to their Toyota Corolla and imagine 50 of them. It’s like talking to grown toddlers sometimes but that have full grown emotional states not under control. Not everyone is like this but a good 50-60% of Americans are. Just look for the Lululemon.
I know that 1kg is about 2.2lbs but that still doesn't give me the "mental clarity" of what 20kg is unless I do the conversion.
At the gym I use the pound plates and not the kilo ones. I intuitively know what the difference between 135 and 225 lbs feels like, and I don't have that same intution for kg.
All that said, I don't find the "small dog" types of analogies for weight very useful. Why not just use the same number of characters (or less) to give the weight in the other popular unit?
Europeans don't even know what it means to "balance a checkbook", so they must be dumber.
Yeah but ya’ll have estates…
It helps to understand that the only freedom Americans only cared for (and the only freedom they have left from the looks of it) is the freedom to choose standards of measurement and vocabulary. This will provide historical context: https://www.youtube.com/watch?v=JYqfVE-fykk (Washington's Dream - SNL)
Huh? Britons get locked up for social media posts. Most of the world doesn’t have guns. And among the first world we’re the only ones free to go bankrupt from medical bills!
Our problems don’t stem from lack of freedom, they stem from too much of it.
> Most of the world doesn’t have guns.
No guns, but they have solar panels, batteries, EVs, etc.
You have the sort of view of America that I can only imagine comes from somebody who has never been here. I don’t know what you mean by batteries, I’m not aware of any we don’t have available.
We have the second most electric vehicles after China, and nearly all new power generation being built here is renewable. I’m not sure how you managed to turn this into some anti-American rant, but at least do a better job of it, it’s very easy.
If I were a self-respecting journalist, I would've used 3.26 gallon milk jugs. Small dog automatically goes to which breed? Chihuahua (fits in a toddlers purse) or Border Collie or Golden Retriever or Saint Bernard (needs an SUV/minivan)? 4 different classifications based on size!
Imperial dog or metric dogge?
Americans are very weird when it comes to metric. They often quote mobile phones as having something like "a six inch screen size but now only 12mm thick" - pick a measurement system people !
Canada is even weirder.
After switching to the metric system ('70-80s) some things are still measures in imperial units. If you slice some ham at a counter in a grocery store, it's in grams. You then turn around and get a pound of apples and a gallon of milk. Nuts are in grams, and soda is in liters. Also the body weight tends to be in pounds. Tools are both metric and imperial. Speeds and distances though, thank god, are metric.
All this is just kinda there and everyone's OK with it, but it is an epic mess if you think about it.
The inch thing is because it's a screen: all screens are measured in inches pretty much everywhere, even in the EU
Yep, inches won for screen sizes.
Aaaand for various fittings for plumbers.
the author and the company are British
Is even a 13 kg dog "small"? It certainly does not feel small if you are carrying it upstairs.
While there’s no formal definition, I think it isn’t. It would be considered medium sized. I live with a 4 lb dog.
I’d say 25-50 lbs would be medium, small below that and large above.
It's American small.
The link you're quoting, the one posted, is a second hand US report.
The primary company link is from a UK subsidiary of Mercedes-Benz and is (almost) fully metric (the fundemental units US weights are officially defined with respect to (for more than a century now)).
See: https://yasa.com/news/yasa-smashes-own-unofficial-power-dens...
Just those pesky trad bhp units left hanging like a chad in a Florida election . . .> The link you're quoting, the one posted, is a second hand US report.
You can tell, because a proper Brit would have given it as 2 stone, not 28 pound.
That seems unlikely, a proper Brit would know that a stone is defined for body weight (14 avoirdupois pounds), Wool (14, 15, or 24 pounds depending on wool class), Wax (12 pounds), Sugar and spice (8 pounds), or for Beef and mutton (8 pounds).
( Of course Scottish Britains used 16 Scottish pounds for a Scottish stone ).
The point being that 'precious' metals used a different weight measure altogether .. (common lead often used a 12 pound stone).
Such a fun system.
Prior to the Revolution, in France alone there were allegedly 250 thousand various units in use! (All sorts of units, not just length.)
It didn't help that pre-Revolutionary France was a political Frankenstein stitched together from dozens of regions with completely different history (Celtic Brittany, Flemish Dunkirk, Germanic Alsace, Provencal South, Catalan Roussillon, Italian Nice) and thus very different local standards of everything, including measurements and law.
Unification of units removed a massive constraint on international trade and engineering. Except the US and Myanmar, of course... it is so frustrating to order anything from Myanmar e-shops, I must say. But Myanmar is at least promising to move on.
Nitpicking: Nice wasn't part of pre-Revolution France, it joined in the 19th century during the Italian unification.
Is that nicepicking, then?
Bag of potatoes?
If you mean a 13kg bag of potatoes, then I'll allow it.
Sometimes leads to humorous effect https://x.com/SheriffAlert/status/1221881862244749315
> Large boulder the size of a small boulder is completely blocking east-bound lane Highway 145 mm78 at Silverpick Rd
But what does this mean for AI...
Feels like a vanity metric, electric car companies don't boast about their cars having X horsepower. Not many people care about horsepower because either way there are speed limits on the road.
I think electric motors should focus on other vectors.
Car companies, both electric and non-electric, frequently advertise rated horsepower of their vehicles, even non-performance vehicles. In the US, horsepower is one of the key metrics for a vehicle overall.
Every car listing, review and so on mentions either the bhp or kW, along with the 0-100km/h or 0-60mph which is functionally the same as listing the horsepower to weight ratio.
Yeah, but 0-60 doesn’t really matter much for EVs at this point. Even big suv/trucks are hitting supercar numbers from a few decades ago.
Cornering / handling matters. So does tire wear, and how powerful the regenerative braking is / how many motors there are. (ABS and traction control via electric powertrains is much more responsive than via brake pads).