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Comment by teiferer | Hacker News Reader

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.

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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.

The article presents it oddly, it's not that the converter maximum input gets lower, it's the solar panel output that gets higher from the nominal quoted value (which is not a maximum, and not really intended to be used as such). Derating your converter is equivalent for the purposes of ensuring margins, but it implies the issue is in the wrong place.

The idea of safety margins has died under the more pressing type - profit margins.

Your safety margin is my profit margin.

- Mr MBA

The failsafe circuit to protect against this (over voltage condition) is maybe $3 and incredibly routine in anything with power. I would bet everything that it is in there.

What's most likely though is that the fuse is also internal, and externally the unit will appear bricked.

While in general most parts will work beyond their ratings to at least some degree, this isn't really a safety margin. A safety margin is known, rated, and validated, and usually a property of a system as opposed to just one part within it.

That’s what I said?

Usually a system would have a safety margin of at least 1.5x, or 3x or the like.

In this case the design safety margin appears to be…. 1x? Exactly?

Suspiciously so. I'd love to see somebody(or somebodies) with an established reputation reverse the controller software & hardware.

Your converter doesn't need to like the voltage, it just can't break from it. In fact, if it's the type that shorts the panels for curtailing, it should be happy to just run them at the highest voltage it's comfortable with, loosing a few percent generation during exceptionally cold days.

> it just can't break from it

In fact, they can.

I think they meant “it just can’t” in the sense of “it shouldn’t under any circumstances”

Even that interpretation would be be wrong because it can and it does and the circumstances are very clearly described. Every inverter worth considering for a home installation has this capability. Only really old ones are not able to disconnect from the HV side when things are about to go pear shaped. If I had an inverter without that capability I'd get rid of it immediately because that's an accident waiting to happen.

Open circuit voltage is _very much_ widely considered to be the maximum. If its not spec'd openly as " at temp X" then it's reasonable to expect it to be invariant.

"Voc 37v @ 25*C"

"Voc 37v"

Edit: Isc is the same- max current.

But that's not true - V_OC for PV modules is nearly always spec'd at STC or NOCT, which is clearly stated on module datasheets along with the temperature coefficient of that voltage.

E.g. choosing a random Jinko datasheet: https://jinkosolarcdn.shwebspace.com/uploads/JKM600-625N-66H...

V_OC is specified at both STC and NOTC, and the datasheet clearly states which environmental conditions accounted for in those test conditions.

It doesn't matter if it's true. And those spec sheets aren't what you'll find on amazon products. I looked at them, didn't see any mention of temperature. Also, stupid things use XT60 connectors. Not remotely appropriate for 150v DC.

I read it as a problem with solar panel voltage going over declared threshold of 37v in certain meteo conditions.

That is the issue is with the wrong labeling of things that are being plugged into this vendor's device, not the vendor's own labeling.

If something can go wrong, it will go wrong. So both parties should note that something can go wrong and point to that something.

I believe the vendor here produces both the device and the panels being plugged into it, and while they also supply other vendors' panels, they seem concerned primarily with customers who buy all components from them and then experience this failure.

I agree the labeling is an issue here, but the solution must come from the wider industry or regulatory bodies; the alternative is for vendors to switch to their own pseudo-units to internalize the math, which would not be good for customers either - think "ACME Generator2000 accepts up to 4 Power Units of input; each ACME SuperEco Panel supplies 1 Power Unit, or 1.5 Power Units if you're in Canada...".

Saving users from having to do a little thinking to not brick their device is a tried-and-true excuse for vendor lock-in in our industry :).

Why not label the panel with the maximum possible voltage that it can produce? Or even have a little table showing the maximum possible voltage at various ambient temperatures. It's not as if there isn't room on the back of the panel for a big enough label.

The entire industry has standardized in having "typical" and "maximum" values decades ago. That problem there is completely self-imposed.

The flip side of this is also dumb labelling. ‘Product may contain traces of nuts’.

Completely unhelpful to those that need the info.

That is in fact useful information to someone that needs that info, because it means they should never eat it. I think this is a bad example, because I have no idea what you're talking about.

Likely a reference to the recent addition of sesame to the allergen disclosure legislation in the US, and the subsequent rampant over labeling.

Nobody seems to remember a bunch of companies receiving rather large fines for pulling known bull-crap "may contain sesame."

This is information is generally stated on the module datasheets, which specify the Open Circuit Voltage (V_OC) at Standard Test Conditions (STC), and then provide a temperature coefficient for how that voltage changes with temperature. 'Maximum voltage' is very arbitrary as this is directly dependant on the lowest expected operating temperature, hence the industry has landed on stating these values at standardized conditions (STC and NOCT) allowing for direct comparison.

The label on the modules themselves tend to also provide these ratings at STC, e.g. this label from Jinko specifies the Open circuit voltage and also summarizes the conditions assumed for STC:

https://image.made-in-china.com/202f0j00LURcYuatWIqH/Jinko-M...

While I agree that the label could also add the temperature coefficient, I'm not sure if it's reasonable to expect that specialist electrical equipment details all of its operating parameters on an attached label without the expectation of consulting a datasheet or manual. For specific products that primarily target non-specialised consumers however, a different labelling approach may be warranted.

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.

There's hiding complexity, and then there's creating fake reality for people.

As it is, panels are gonna produce variable power depending on the weather. Putting interoperability with third-party panels aside, to get the simplicity of "max 2 panels in series", they'd have to either cap the max power on the panel/generator link and dump the excess, or set the limit based on the worst case a customer is likely to encounter. I.e. they're either gonna waste power, or gouge their customers for extra hardware. Neither of that makes sense for an ecological product sold to a price-conscious customer base :).

The problem is that you run higher voltages with the same hardware if your in Alaska than if you're in Florida. Substantially so.

"Wasting" those 5~10% during severe winter conditions isn't worth splurging on the voltage converter.

Though then selling units that suggest to not run a few hundred volt strings before paralleling instead does sound bad, as the string doesn't need separate fuses rated to many volts DC.

> 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.

> 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.

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.

> 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.

But they want you to have to buy another one.

Why does this kind of comment get downvoted that pinpoints the actual motivation? We just pretend that planned obsolescence is history.

At least in parent's case, probably because the vast majority of their comments are black-and-white hot takes that are always downvoted regardless. And they basically never respond when asked for any sources.

Yeah bad faith commenter then

Voting based on ad hominem is against HN guidelines.

I’m sorry who did you mean to say this to? Not sure this is relevant here

Because it’s an extreme claim backed up with no evidence. Hanlon’s razor applies here.

Also see Hitchens' razor and Russel's teapot.

To me, 220 sounds 20 like lower than 240. I have a hunch that this might be a common perception.

Really?

I have all sorts of electronics that say everything from 208V - 240V that all go in the wall, so I think all those numbers are probably close to each other in whatever a volt is.

I think if I'm worried about a limit of some kind, being within 5% of that limit seems like I might as well be over-limit if the commonly seen distribution I see in my house is greater than 15%

I have a lot of electronics that accept 100-240v doesn’t mean I think they’re close together, just that they have compensating mechanisms to handle such voltages.

The margins are generally lower for higher power devices because the electronics are more expensive. Thankfully these electronics in general are becoming cheaper which is one reason why they’re ending up in the hands of people inexperienced with them.

Also try to tell someone they need an extra 30% in margin and often they'll think they’re being upsold.

> I have a lot of electronics that accept 100-240v doesn’t mean I think they’re close together, just that they have compensating mechanisms to handle such voltages.

I bet you also have a lot of electronics that don't though, and those that do probably say so.

My kitchen mixers, dishwasher, washing machine, driers, rice cooker, refrigerators, sauna, and pool pump aren't that tolerant by a long shot. I've got a few computers with a switch on the back to choose between 220v and 110v.

Plugging something that takes 110v into my house breaks the thing, so I've learned to check.

But I don't have anything that's 208v that can't go into the house. So I think whatever the situation is with volts, within 15% is "basically the same", so coming within 15% of the rated limit, is probably just like exceeding the limit by 15%.

And so this is why I would not expect something at 146V to be under the safety limit of 150V.

> Also try to tell someone they need an extra 30% in margin and often they'll think they’re being upsold.

Where do you get 30%?

You’re listing things that are high powered and or old. Modern PSUs don’t have that switch. While it’s in the early stages I expect more white goods to switch to BLDC motors which will likely use voltage transformers that’ll support the 110-240v.

People generally are not lugging white goods internationally, the average persons experience with different voltages is for laptop and phone chargers when they travel.

But for the matter at hand, the margin mentioned is needed on the solar systems, this is where the inverters can get expensive, which is why it can look like an unnecessary upsell to people who’ve never blown a device before.

> You’re listing things that are high powered and or old.

Sure. I have high-powered and old things, and I bet you've seen stuff like that too.

I'm explaining why I, as a non-expert, would not put 146V into something that says it can't take more than 150V.

> People generally are not lugging white goods internationally

Travel doesn't enter into it; My appliances came from Europe, they're just labelled a bunch of different voltages, so I think voltages within that range are roughly equivalent.

Furthermore, British have such a very special relationship with tea, such it would be entirely understandable that a Brit would take their kettle with them and often become quite annoyed that they cannot get an adapter to use it when holidaying amongst the yanks.

Not sure what I expected from someone who thinks 208V and 240V are close together from some labels they saw on some devices.

US appliances using single-phase power work between 208V and 240V so they work on both residential and commercial electrical systems.

Line-to-line voltage on a three-phase 208V system is 208V, line-to-line on 240V single-phase system is 240V.

Most commercial lighting products are rated for 120V-277V so they work on both residential and commercial (480/277V line-to-neutral single phase voltage is 277V)

> Idk. I don't have a PHD, but 220V sounds like 240V to me. I wouldn't do this.

220[Vrms] * 1.414 = 311[Vp-p] btw. HOW!?

AC wiggles and wobbles.

So the issue is that 220V is nominal in China, 230V nominal in UE and 240V is UK/part of Australia. So if anyone is preparing product for global market (as most are doing now) more likely then not will support all of this voltages. Thus is kind of normal (but wrong) to assume 220V sounds like 240V.

When the voltage was unified in UE, the nominal value was set to the median of 230 V, but its tolerance was raised from 10% to 15%, so that the new maximum peak value of 230V + 15% will match the old value of 240 V + 10%.

So now for all 220/230/240 V standards you have the same maximum voltage value that is used for electrical designs (about 265 V effective), so they are equivalent, regardless of the name.

True, however there is also old equipment. For example I have heard that light bulbs designed for 220V will last for noticeably shorter period of time ar 230V nominal circuit. That is why it is worth to check supported voltage. But you are right - newer equipment will suport all voltages.

Many charguers are now 100-240V, 50-60Hz, that is close to pluggable anywhere on Earth. (I burned one or two a long time ago, when I forgot to check and used a 120V transformed here with 220V)

Same thing happened to PC PSUs. I don't think there is a recent unit that still has the self-destruct voltage selector switch which pops them if you are in 230V land (and the switch is set to the smaller setting).

Besides the ratio between the peak and effective value, you must also account for the standard tolerance of the nominal value.

The actual maximum peak voltage for the European mains, is 230 V * 1.15 * sqrt(2), because of a 15% tolerance. That is about 375 V. With a small safety margin, the minimum voltage rating for components connected to 230 V a.k.a. 220 V is of 400 volt.

Makes me wonder if that was how EV DCFC quickly settled with 400VDC. The voltage makes sense if it was somehow known that engineers has intuitions with safe designs for 400Vp-p systems.

I would be wary of relating any DC constraints to AC constraints and behaviour.

> make it more resiliant, rather than blaming customers

Yeah, this sounds very much like "you're holding it wrong".

They can add a relay, I guess? Voltage monitoring is cheap. Relays might push price above a bit, but it's a worthy premium to pay in my book.

Considering the electric code has an 80% rule for loads, anyone assuming they can use 100% of what is on a label probably should not be doing electrical work.

Very true. My computer says 240V on it, so I should only use it up to 192V.

No, you just shouldn't assume that that's the case. In the case of a computer and mains, both of those are nominal voltages and there will be a range of voltages which are expected to function, and if you want to check for sure, you should check those ranges.

The point is, voltages are usually a 1:1 match. That includes when you're working with ranges, you want the supply range to be inside the load range.

And even for amps where you see that 80% rule, that's for keeping the load smaller than the supply. Solar panels aren't a load and don't work that way.

Interestingly, the peak voltage of 240V AC (typical) is 330ish+ volts.

Typical house wiring is required to handle 600v due to voltage transients and wear and tear.

So any component rated to 240V dc will fail immediately on AC, and even 400-500V DC is not a good idea.

I guess there is a reason there is a whole category of engineers for this kind of thing.

Which electrical code? They vary from country to country and even state/province in some countries!

I agree with you, but. The NEC has an 80% rule for continuous loads (over 3 hours) that use a typical circuit breaker as overcurrent protection. If you use fuses or a 100% rated breaker as your over current protection, then you can use all of the available ampacity. Anyways, devices that use a 15A receptacle (for example) will not draw more than 12A continuous if they’re meant to run continuously (3 hours or longer).

https://www.se.com/us/en/faqs/FA104355/

This feels a bit like the logic behind "do not put hamster in microwave" warning labels.

I think if you work with electrical or electronic systems in practice, you learn pretty quickly to respect tolerances and that data sheets are a map, not the territory.

Also, electrical installations are usually seen as a field that should be done by trained personnel, not arbitrary laymen home owners. So I think the appropriate reaction would be to remind people that they should hire an electrician to do the installation, if they don't have the necessary specialized knowledge themselves.

I have the impression these are consumer products so I would them to be designed to be installed by people who do not normally work with electrical systems. If they are only sold to tradesmen that would be different.

Yeah, it would be important to understand who the company is intending to sell to or do the installation.

Though the lines are often blurred, because I guess most companies would like to sell directly to end customers, even if their product requires a professional to install.

Even IKEA does this. You can go in and buy an electric stove and oven, grab them from the warehouse and take them home with you right there. But it's a bit of an illusion: You're still supposed to call an electrician to actually connect the things.

> Yeah, it would be important to understand who the company is intending to sell to or do the installation

You can do that by just reading the product page[1]. The delta pro, the equipment in question, looks like a plug-in appliance. It visually communicates that it is portable (by having a wheel and a handle) and by virtue of having a power lead connect to it it communicates that you can just plug it in. They further reinforce this by writing this: "Plug & Play home backup solution". "Easy installation with completely pre-wired Plug & play home backup solution" "The solution provides a convenient home battery system without rewiring or running dangerous extension cables through your home." "Plug directly into an AC wall outlet and make sure that the wall output current is more than 15A."

And on top of that the manual[2] makes no mention of needing an electrician.

In contrast an IKEA electric oven's product page[3] states this: "No plug is included. Installation to be carried out by a qualified installer." and then the manual[4] states "Installation, including water supply (if any) and electrical connections, and repairs must be carried out by a qualified technician."

But of course nobody reads the manual. The big difference is that one comes with a plug while the other doesn't.

1: https://us.ecoflow.com/products/delta-pro-portable-power-sta...

2: https://websiteoss.ecoflow.com/cms/upload/2022/10/12/1312845...

3: https://www.ikea.com/gb/en/p/mataelskare-forced-air-oven-ike...

4: https://www.ikea.com/in/en/manuals/matalskare-forced-air-ove...

If you can do a code compliant installation, then you’re the customer. If you can’t, then I’d suggest hiring an electrician.

Actually if "you work with electrical or electronic systems in practice" you get pissed off at everything for how dumb it all is: 12V DC batteries are more like 14 nominal? AC wall plugs dip voltage when printers turn on, random equipment you arent even sure in the building can trigger UPSes based on unknown settings in the device? International standards and communication protocols mean nothing as "a standard" because each company has their own entire list of bugs/implementation mistakes. All the international enforcement certifications care way too much about inconsequential bullshit and miss all the true showstopping problems in most industries?

This world is amazing anything runs at all. The slightest addition of complexity is causing everything to fail now.

Modern computers are less reliable than ever, some companies have decided to REMOVE the pinhole bios reset (that has been around for 30 years) at the same time as things are buggier now and dont boot again until you physically unplug the bios battery deep inside and hard to get to.

Spoken like a true professional!

The modern engineer:

It works! OK, stop touching it. We don't want to break it.

This is what makes software engineering so seductive, everything works exactly as it was designed to (whether intended or not). Imagine trying to program for computers with memory that drifts values progressively more as it wears down.

So on the one hand we have a product which isn't even remotely designed for the use case (hamsters), and during normal use shows obvious behaviour (cooking) that should imply risk to said hamsters. On the other side, we have a product designed to be installed in an electrical system, and shows no signs during normal use that it's installed unsafely, and where the advertised specs are not actually safe for normal usage.

Whether or not the company in this case shares some or most of the blame with novice users - the analogy is not a great one.

Microwaves were originally specifically invented to microwave frozen hamsters:

https://interestingengineering.com/videos/1950s-reanimating-...

As Doc Brown would say, "Great Scott!"

Hyper amusing, thanks for sharing! Doesn't really improve the analogy, but fun quirk of history :-D.

I don’t know about the components they’re selling, but with electronic components, it’s on the buyer to properly read the data sheet and understand what the quoted nominal specs mean.

Unless it’s safety critical, you usually don’t want a system with a bunch of active electronics to prevent someone wiring it up wrong, because those components will interfere with whatever you’re hooking it up to, such as the MPPT, the battery, or whatever else.

This is like how AA batteries have a nominal voltage of 1.5V but the actual open circuit voltage is 0.9V~1.65V depending on charge level, temperature, etc. If you connect an AA to something that’ll explode at a voltage of 1.55V, that’s on you.

Similarly if you buy a 470 ohm resistor, you will find in on the data sheet that’s usually at 20°C. To know what it’ll be at any other temperature, you’ll need to use the temperature coefficient to calculate it.

This isn’t electronic components, this is sold as a consumer level gadget that anyone can use. No one expects a standard consumer to understand data sheets like that.

You started off by saying you don’t know about the components they’re selling - but that turns out to be absolutely critical to understanding the context here.

Either way, I can’t believe they just let it fry the main board instead of having a sacrificial fuse or equivalent go first in these scenarios, whether it was a product aimed at professionals or not. It’s just dumb.

I don't know how this would be perceived in the US, but in UK/Europe this wouldn't be seen as or regulated as a "consumer level gadget".

It's a main-voltage electrical system. I'm not even sure it would be legal for an electrician without the appropriate qualifications to commercially commission one of these systems. Their website even says installations should be performed by "a licensed electrician or a qualified professional."

In practice, every single solar system I've seen is exactly the same as this one.

A fuse wouldn't help here because they're current protection devices but we're talking about voltages here. Voltages are harder to generically protect against with a sacrificial device, and also over-voltage protection devices themselves have a habit of catching fire even when the voltage is within limits so you probably don't want one right next to your lithium batteries anyway. You'll even find most consumer devices don't have much in the way of continuous overvoltage protection.

It's typical when commissioning solar to just "protect" from panel overvoltage by ensuring your panel outputs are well within the margin of your MPPT (this device appears to be an a combined MPPT, inverter and battery) on a worst case cold day. Really there's just no reason to run your panels right up against the MPPT max voltage.

Given how easy it is to protect against design overvoltage by designing your panel circuits suitably, and how overvoltage protection devices are themselves a point of (potentially catastrophic) failure, I think it's pretty hard to make the case for including one as standard, which is why nobody does.

But leaving this particular issue aside, these devices are totally not suitable for consumer installations unless you like fires.

In your AA batteries analogy, this is like saying that you do not need to state that the device exploding at 1.55V would do so, not about battery declarations (panels in this case).

It wasn't meant to be a direct analogy, just a simple example of how you get similar situations in general with electronic components, or really any kind of non-standalone component in most industries. Another example is fuses: a fuse rated at 20A will not immediately protect the downstream once load exceeds 20A, but rather, there will be a curve defined with respect to its nominal rating which defines how long it will take to burn out for any given current and ambient temperature. You may find at 20C, it will not even burn out at a continuous load of 25A, and at 30A it might take 2 hours. So if you're buying a fuse to protect a sensitive downstream circuit, you need to take that into account and use a fuse that's nominally smaller than the load you're running.

Essentially the "nominal" behaviour is not the actual behaviour, it's just a quick way of summarising the characteristics in a way that someone familiar with the class of item will be able to understand what they're buying. Another similar situation is timber sizing, where a 2" by 4" is actually 1.5" x 3.5".

In the case of electronic components, the actual behaviour will be either documented in a datasheet or just common knowledge in the industry. For example if you're buying a standard li-ion battery with no active circuitry, you'll often find the datasheet quite lacking in details because you are expected to just know the characteristics of the li-ion chemistry provided the basic parameters are provided.

Got it, thanks for diving deeper!

Maybe it would be a good idea to at least add a pair of MOSFETs (one for each rail, + and -) and a voltage meter? Like, the voltage doesn't rise to maximum instantaneously, there should be ample of time to detect voltage rising to a critical amount.

So say, the input is rated for 150V, spec the components to sustain 180V, and trigger the MOSFETs to disconnect the panels at > 160V.

And maybe also add a big ass buffer capacitor, that can be used to soak up a bit more energy in the case of an inrush spike before the MOSFETs actually disconnect.

MosFET's or IGBTs are likely what failed. And, capacitance is something you do not want on a string of PV.

DC starts getting really nasty to deal with somewhere between 36-52v, with 150v of panels not being something joe-blow should be able to buy on amazon. Designing these systems to be safe is difficult.

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