Maybe they should just improve their product to make it more resiliant, rather than blaming customers for thinking that 148 V is below 150 V? Not everybody buying these has a Ph.D. in physics and if it says 148 V on the label and 150 V on the other label then it's your product that has a problem, not the customer.
And no matter what happens, customer support should help the customer, not blame them.
This is 100% on the manufacturer if they intentionally chose to highlight the "best case" 150V, rather than the 120V lower end. Especially without any additional safety mechanisms.
> Not everybody buying these has a Ph.D. in physics and if it says 148 V on the label and 150 V on the other label then it's your product that has a problem, not the customer.
Idk. I don't have a PHD, but 220V sounds like 240V to me. I wouldn't do this.
I feel like getting advice about how to wire up electronics should not be so hard.
> Maybe they should just improve their product to make it more resiliant
Adding "resilience" usually adds to the per-unit cost. I think making a web page adds some cost too, but at least that can be amortised.
> And no matter what happens, customer support should help the customer, not blame them.
I think that's happening here: Making a web page to educate future customers seems like a really good idea. I wouldn't have thought that necessary until I saw it, but I'm always excited to learn something new.
The existing customers who did dumb should consider this a relatively cheap education in electronics; cheaper than a PHD at least!
Also, whether the company also gave them rebates or credits we don't know here, but telling "customer support" they "should help the customer" is also telling them they're not helping the customer, and you don't know that.
They're just being cheap. If you're going to let customers plug panels directly into your box you should have overvoltage protection. It's that simple.
> Making a web page to educate future customers seems like a really good idea
I don't think this is an official website of ecoflow.
Other than that I agree. I don't think asking for a bit of knowledge from the customers is a bad thing. A warning in the manual about safety factors should be enough.
Why doesn't this just produce a shutdown? Inverters have to track voltage and current on the input and outputs sides, and can turn themselves off. They shouldn't be that close to the absolute maximum voltage ratings on the components.
Too much current is a heat dissipation problem, and you've got some time to deal with that, at least tens of milliseconds.
Anyone have a teardown on these things? Are they using under-rated MOSFETs? That's all too common in solid state relays from China.
High voltage, low RDSON FETs are (slightly) more expensive, and these products are cheap. A better design would use a higher-voltage rated input switch with poor (slow) switching performance, like an IGBT. Don’t design critical infrastructure around EcoFlow hardware.
Fujitsu, which sells MOSFETs for this application, writes: "Firstly devices should be rated at 600V or 650V, as this will generally provide more than adequate protection against the threat of high voltage transients."[1] That's a nice big safety margin. It should hold until the voltage monitoring shuts the whole thing off.
Not seeing UL certification on this thing.
If we're going to have US protectionism against China, a good first step would be to require UL-type testing, carried out in the US, on all imported electrical devices that run on more than 12VDC or contain a battery chemistry capable of thermal runaway. Electrical safety is a solved problem if you can keep people from cheating.
> Plugging in four 400w solar panels in series is similar to filling your gasoline powered car with diesel and wondering why the car manufacturer isn't replacing your new car.
I don’t think this analogy works. The solar input works like Diesel or Gasoline in different temperature. It’s pretty unreasonable to assume the consumer knows when depending on temperature unless the explicitly state in the manual (I’m willing to bet good money majority of the people in US have never read their car manual either)
I was going to comment on the manufacturer's safety margins, but then I found a graph [1] on the variability of voltage vs temperature and it seems to be a lot steeper than I thought/expected, to the point that I'm wondering how these do not require either training or a voltage regulator to install and operate properly:
Basically anything that consumes solar power incorporates what's called a "MPPT", or maximum power point tracker.
Basically, it's a smart DC-DC converter that continually tracks the voltage/current output of a solar panel and adjusts the load to extract the maximum available power from the panel.
It's not uncommon to have issues with extremely high panel voltages in snowy climates, when they're first illuminated in the morning. If you are close to the maximum voltage your MPPT charger can handle in normal circumstances, extreme cold can even damage things during the initial morning transient. You then have to do oddball things like use a crowbar system to prevent blowing up your MPPT system.
I never tried the solar charging on my ecoflow so this fragility surprises me a bit.
I've been able to run laundry in a machine with a 1/2hp motor using the inverter side on multiple occasions. No smoke or funny smells. My 2200w generator would trip out the instant the spin cycle tried to start.
Why isn't there code/regulations for tbis. Why do you need blog advice.
It is like using too thin wiring to your oven or something. Because you based it off how you typically use the oven not is max draw plus decent margin.
Which is why you get a qualified electrician who knows or get qualified yourself.
When I got solar panels for my (former) house 15 years ago, as I recall, the best practice was to have panels in parallel (each with its own microinverter) and not in serial as serial would cause loss of efficiency when there was partial blockage of panels. (I could be misremembering all of this).
A few years ago, I plugged a single 100W solar panel into a battery pack that advertised it accepts 18 volts. I left it plugged in, on my deck, for hours. When I came back, there was a foul smell and some parts of the battery pack had turned black, apparently from getting charred. The battery pack no longer worked at all. I was very fortunate that only the control circuit had been destroyed and the battery cells (and my deck) had not been touched.
Lesson learned: don't skimp on Li-ion battery packs!
Also, I have a question about this article. Don't EcoFlow battery packs have a circuit that checks the incoming voltage and automatically shuts off charging if the voltage is too high? I would also expect a loud alert.
I am surprised that open circuit voltage is specified at 25°C and increases dramatically as the temperature goes down. Seems backwards! I'm looking at the Ecoflow spec sheet right now and fair enough, it's got the open circuit voltage and then the Temperature Coefficient of Open Circuit Voltage (-0.35%/°C) right next to it.
Great, guys, how about you go ahead and multiply those two numbers for me, since you're the ones writing the fucking spec sheet? It's like if car battery manufacturers only specified a cranking amps number, and told you to figure out cold cranking amps yourself.
Why does the Delta Pro not have a fuse on the input, with the MPPT limiting the max voltage to 150v (by upping the current until the voltage sags and/or the fuse blows, or even a straight crowbar circuit). This is a premium consumer brand selling a mostly complete product, and protecting the input from overvoltage would be straightforward. The frustration at the warranty weaseling isn't surprising.
You might think that the voltage rise could be too fast for most protective technologies to save the downstream electronics, but the general case is that the temperature slowly drops and the sun slowly rises. So the voltage should slowly approach the limit.
Adding a normally-open relay and a voltmeter and a microcontroller should fix this. Relay won't close on startup unless the voltage is safe. Microcontroller will open the relay if the voltage gradually nears the limit. Should be solvable for <$5 in parts.
Dark start (when the batteries are flat w/o grid power) will be challenging. There will need to be a small battery to power the voltmeter and relay, or a high-voltage tolerant supply to power the microcontroller and relay temporarily. A 9V should likely be sufficient.
Common relays don't handle 150VDC, and I'd spec the voltage even higher even though one would think the voltage rating has more to do with arc interruption rather than creepage while off. Also a microcontroller is complete overkill, draws too much current to be easily powerable by the solar panel side, and adds complexity for something to go wrong. A simple analog comparator suffices.
The standard answer for overvoltage protection is a crowbar circuit + fuse, and I think that's what I'd aim for rather than a relay. The problem with DIYing that is knowing the input capacitance of the Delta and finding out whether it has any other problems with its input being abruptly shorted.
It’s not that it lowers the maximum voltage that the charge controller/inverter can handle. It’s actually that the panels become MORE efficient in the cold temperatures, resulting in a (potentially unconsidered by end-user) increase in voltage, overwhelming the downstream BoS components.
Lower temperatures increase PV max voltage output, not lower it. Conversely, when solar panel temperature increases, voltage decreases. So the headline specs/outputs assume to be valid at a particular temperature. As the temperature of the panels change, the realized performance changes.
Solar panel voltage goes up as temperature decreases. The chart is misleading, it's stating something like an equivalent max voltage if you think of the solar cell voltage as staying the same (and presuming your temperature coefficient matches)
The subtitle is, though, and I do find a problem with it. There might be someone out there (possibly not sober) who thinks "Magic smoke? Let's see some!" It also somewhat distorts the original. It should be more like "unless you want the magic smoke to escape." The smoke's magic properties are gone once that happens. At least, nobody has ever proven the escapee smoke has any.
I’ve never heard it called magic smoke before, but a regular saying at one of my old jobs was “ah yeah we let the smoke out” in relation to 100% electric drive vehicles. Smoked many inverters, shorted 96v bus to a 24v bus, etc.
It was almost a rite of passage to “let the smoke out” in that org. That job was actually great because as a software engineer I happily spent a lot of time with a fluke, a wrench, arm buried in the bowels of a vehicle fishing out sockets, etc. Writing the software was not the hardest part of those programs, but being one of the handful of folks that knew the entire electrical, cooling, mechanical, and software systems made us the most valuable folks on the program. We had to know all those things in order to write the software correctly.
Maybe they should just improve their product to make it more resiliant, rather than blaming customers for thinking that 148 V is below 150 V? Not everybody buying these has a Ph.D. in physics and if it says 148 V on the label and 150 V on the other label then it's your product that has a problem, not the customer.
And no matter what happens, customer support should help the customer, not blame them.
This is 100% on the manufacturer if they intentionally chose to highlight the "best case" 150V, rather than the 120V lower end. Especially without any additional safety mechanisms.
In both examples given you can have 2 panels in series.
So given that in almost all use cases, you can have 2 panels in series, they should just say “max 2 panels in series”. Simple.
A good product hides complexity from the user with sane defaults and optional advanced configuration. This feels like the same problem.
Panels are not standardized and are themselves series-parallel constructions with wildly diverse specs.
> Not everybody buying these has a Ph.D. in physics and if it says 148 V on the label and 150 V on the other label then it's your product that has a problem, not the customer.
Idk. I don't have a PHD, but 220V sounds like 240V to me. I wouldn't do this.
I feel like getting advice about how to wire up electronics should not be so hard.
> Maybe they should just improve their product to make it more resiliant
Adding "resilience" usually adds to the per-unit cost. I think making a web page adds some cost too, but at least that can be amortised.
> And no matter what happens, customer support should help the customer, not blame them.
I think that's happening here: Making a web page to educate future customers seems like a really good idea. I wouldn't have thought that necessary until I saw it, but I'm always excited to learn something new.
The existing customers who did dumb should consider this a relatively cheap education in electronics; cheaper than a PHD at least!
Also, whether the company also gave them rebates or credits we don't know here, but telling "customer support" they "should help the customer" is also telling them they're not helping the customer, and you don't know that.
To me, 220 sounds 20 like lower than 240. I have a hunch that this might be a common perception.
> Adding "resilience" usually adds to the per-unit cost.
In this case, the cost is much less than a dollar (say, a varistor that blows the existing fuse) and it prevents a catastrophic failure.
They're just being cheap. If you're going to let customers plug panels directly into your box you should have overvoltage protection. It's that simple.
> Making a web page to educate future customers seems like a really good idea
I don't think this is an official website of ecoflow.
Other than that I agree. I don't think asking for a bit of knowledge from the customers is a bad thing. A warning in the manual about safety factors should be enough.
Why doesn't this just produce a shutdown? Inverters have to track voltage and current on the input and outputs sides, and can turn themselves off. They shouldn't be that close to the absolute maximum voltage ratings on the components.
Too much current is a heat dissipation problem, and you've got some time to deal with that, at least tens of milliseconds.
Anyone have a teardown on these things? Are they using under-rated MOSFETs? That's all too common in solid state relays from China.
High voltage, low RDSON FETs are (slightly) more expensive, and these products are cheap. A better design would use a higher-voltage rated input switch with poor (slow) switching performance, like an IGBT. Don’t design critical infrastructure around EcoFlow hardware.
Fujitsu, which sells MOSFETs for this application, writes: "Firstly devices should be rated at 600V or 650V, as this will generally provide more than adequate protection against the threat of high voltage transients."[1] That's a nice big safety margin. It should hold until the voltage monitoring shuts the whole thing off.
Not seeing UL certification on this thing.
If we're going to have US protectionism against China, a good first step would be to require UL-type testing, carried out in the US, on all imported electrical devices that run on more than 12VDC or contain a battery chemistry capable of thermal runaway. Electrical safety is a solved problem if you can keep people from cheating.
[1] https://toshiba.semicon-storage.com/eu/semiconductor/design-...
> Plugging in four 400w solar panels in series is similar to filling your gasoline powered car with diesel and wondering why the car manufacturer isn't replacing your new car.
I don’t think this analogy works. The solar input works like Diesel or Gasoline in different temperature. It’s pretty unreasonable to assume the consumer knows when depending on temperature unless the explicitly state in the manual (I’m willing to bet good money majority of the people in US have never read their car manual either)
Agreed. No one needs to change which type of gas they use because it happens to be a warm sunny day.
I was going to comment on the manufacturer's safety margins, but then I found a graph [1] on the variability of voltage vs temperature and it seems to be a lot steeper than I thought/expected, to the point that I'm wondering how these do not require either training or a voltage regulator to install and operate properly:
https://www.researchgate.net/figure/Module-voltage-current-v...
They do!
Basically anything that consumes solar power incorporates what's called a "MPPT", or maximum power point tracker.
Basically, it's a smart DC-DC converter that continually tracks the voltage/current output of a solar panel and adjusts the load to extract the maximum available power from the panel.
It's not uncommon to have issues with extremely high panel voltages in snowy climates, when they're first illuminated in the morning. If you are close to the maximum voltage your MPPT charger can handle in normal circumstances, extreme cold can even damage things during the initial morning transient. You then have to do oddball things like use a crowbar system to prevent blowing up your MPPT system.
(see https://en.wikipedia.org/wiki/Maximum_power_point_tracking )
I never tried the solar charging on my ecoflow so this fragility surprises me a bit.
I've been able to run laundry in a machine with a 1/2hp motor using the inverter side on multiple occasions. No smoke or funny smells. My 2200w generator would trip out the instant the spin cycle tried to start.
Why isn't there code/regulations for tbis. Why do you need blog advice.
It is like using too thin wiring to your oven or something. Because you based it off how you typically use the oven not is max draw plus decent margin.
Which is why you get a qualified electrician who knows or get qualified yourself.
When I got solar panels for my (former) house 15 years ago, as I recall, the best practice was to have panels in parallel (each with its own microinverter) and not in serial as serial would cause loss of efficiency when there was partial blockage of panels. (I could be misremembering all of this).
you might be misremembering bypass diodes?
No, microinverters are still a thing (Enphase is a popular brand) and they do then get connected in parallel.
A few years ago, I plugged a single 100W solar panel into a battery pack that advertised it accepts 18 volts. I left it plugged in, on my deck, for hours. When I came back, there was a foul smell and some parts of the battery pack had turned black, apparently from getting charred. The battery pack no longer worked at all. I was very fortunate that only the control circuit had been destroyed and the battery cells (and my deck) had not been touched.
Lesson learned: don't skimp on Li-ion battery packs!
Also, I have a question about this article. Don't EcoFlow battery packs have a circuit that checks the incoming voltage and automatically shuts off charging if the voltage is too high? I would also expect a loud alert.
I am surprised that open circuit voltage is specified at 25°C and increases dramatically as the temperature goes down. Seems backwards! I'm looking at the Ecoflow spec sheet right now and fair enough, it's got the open circuit voltage and then the Temperature Coefficient of Open Circuit Voltage (-0.35%/°C) right next to it.
Great, guys, how about you go ahead and multiply those two numbers for me, since you're the ones writing the fucking spec sheet? It's like if car battery manufacturers only specified a cranking amps number, and told you to figure out cold cranking amps yourself.
> Great, guys, how about you go ahead and multiply those two numbers for me, since you're the ones writing the fucking spec sheet?
No time. Busy writing blog posts blaming customers.
Why does the Delta Pro not have a fuse on the input, with the MPPT limiting the max voltage to 150v (by upping the current until the voltage sags and/or the fuse blows, or even a straight crowbar circuit). This is a premium consumer brand selling a mostly complete product, and protecting the input from overvoltage would be straightforward. The frustration at the warranty weaseling isn't surprising.
You might think that the voltage rise could be too fast for most protective technologies to save the downstream electronics, but the general case is that the temperature slowly drops and the sun slowly rises. So the voltage should slowly approach the limit.
Adding a normally-open relay and a voltmeter and a microcontroller should fix this. Relay won't close on startup unless the voltage is safe. Microcontroller will open the relay if the voltage gradually nears the limit. Should be solvable for <$5 in parts.
Dark start (when the batteries are flat w/o grid power) will be challenging. There will need to be a small battery to power the voltmeter and relay, or a high-voltage tolerant supply to power the microcontroller and relay temporarily. A 9V should likely be sufficient.
Common relays don't handle 150VDC, and I'd spec the voltage even higher even though one would think the voltage rating has more to do with arc interruption rather than creepage while off. Also a microcontroller is complete overkill, draws too much current to be easily powerable by the solar panel side, and adds complexity for something to go wrong. A simple analog comparator suffices.
The standard answer for overvoltage protection is a crowbar circuit + fuse, and I think that's what I'd aim for rather than a relay. The problem with DIYing that is knowing the input capacitance of the Delta and finding out whether it has any other problems with its input being abruptly shorted.
Why would lower temperatures lower the maximum voltage?
Sure, diode forward voltages change a little but seems like something else is going on…
It’s not that it lowers the maximum voltage that the charge controller/inverter can handle. It’s actually that the panels become MORE efficient in the cold temperatures, resulting in a (potentially unconsidered by end-user) increase in voltage, overwhelming the downstream BoS components.
Lower temperatures increase PV max voltage output, not lower it. Conversely, when solar panel temperature increases, voltage decreases. So the headline specs/outputs assume to be valid at a particular temperature. As the temperature of the panels change, the realized performance changes.
Solar panel voltage goes up as temperature decreases. The chart is misleading, it's stating something like an equivalent max voltage if you think of the solar cell voltage as staying the same (and presuming your temperature coefficient matches)
Current title is actually a subtitle. Actual title:
`Solar Panels + Cold = A Potential Problem`
The subtitle is, though, and I do find a problem with it. There might be someone out there (possibly not sober) who thinks "Magic smoke? Let's see some!" It also somewhat distorts the original. It should be more like "unless you want the magic smoke to escape." The smoke's magic properties are gone once that happens. At least, nobody has ever proven the escapee smoke has any.
To be honest I went into it half expecting it to be about papal elections[1].
[1] https://theconversation.com/conclave-the-chemistry-behind-th...
I am sure many are familiar but I found it amusing when someone explained to me why it is called magic smoke.
It is because electronics work through magic so when you let the magic smoke out, they stop working.
Devices run on magic smoke. When something bad happens the smoke escapes and thus the device no longer works.
This is proven by observation - the only thing you see charge is the smoke escaping.
The presentation helps a lot too, the way I was told it was something like:
“Did you know that computers actually run on magic smoke? Once the magic smoke comes out though, it stops working.”
It's the soul leaving the IC.
I’ve never heard it called magic smoke before, but a regular saying at one of my old jobs was “ah yeah we let the smoke out” in relation to 100% electric drive vehicles. Smoked many inverters, shorted 96v bus to a 24v bus, etc.
It was almost a rite of passage to “let the smoke out” in that org. That job was actually great because as a software engineer I happily spent a lot of time with a fluke, a wrench, arm buried in the bowels of a vehicle fishing out sockets, etc. Writing the software was not the hardest part of those programs, but being one of the handful of folks that knew the entire electrical, cooling, mechanical, and software systems made us the most valuable folks on the program. We had to know all those things in order to write the software correctly.
In the early 80s we used to say electronics ran on magic pixie dust, and when you let the pixie dust out as smoke, the magic went away.