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Solar panels + cold = A potential problem

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Re: Solar panels + cold = A potential problem

#171

Post by quickthrowman »

harvey9 wrote: post #48
xg15 wrote: post #46

Earlier quoted context omitted.

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…

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.

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

Re: Solar panels + cold = A potential problem

#172

Post by quickthrowman »

cowsandmilk wrote: post #94
teiferer wrote: post #25

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.

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.

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/

Re: Solar panels + cold = A potential problem

#173

Post by cjbgkagh »

geocar wrote: post #154
cjbgkagh wrote: post #115

Earlier quoted context omitted.

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…

> 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 com…

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.

Re: Solar panels + cold = A potential problem

#174

Post by privatelypublic »

mschuster91 wrote: post #167
teiferer wrote: post #25

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.

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…

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.

Re: Solar panels + cold = A potential problem

#175

Post by dotancohen »

jacquesm wrote: post #161
dotancohen wrote: post #158

Earlier quoted context omitted.

I'm sure that home mains would have no problem, but a solar installation might. Would a small li-ion help smooth over those amperage hills?

It would help at noon, when usually inverters make so much power they push the local grid to saturation which causes them to disconnect from the grid for a while. There are different rules for this for different localities, typically the installer will pick the regime appropriate for the local grid. Where I live (NL) the voltage is allowed to hit 253V for up to a minute, if it takes longer than that my inverters will…

I actually meant a small li-ion inside the appliance, to smooth out the load. Do any batteries support 20C or 30C? That seems like enough to smooth such a load.

Re: Solar panels + cold = A potential problem

#176

Post by jacquesm »

dotancohen wrote: post #175
jacquesm wrote: post #161

Earlier quoted context omitted.

It would help at noon, when usually inverters make so much power they push the local grid to saturation which causes them to disconnect from the grid for a while. There are different rules for this for different localities, typically the installer will pick the regime appropriate for the local grid. Where I live (NL) the voltage is allowed to hit 253V for up to a minute, if it takes longer than that my inverters will…

I actually meant a small li-ion inside the appliance, to smooth out the load. Do any batteries support 20C or 30C? That seems like enough to smooth such a load.

That's a very complex and potentially dangerous device.

Re: Solar panels + cold = A potential problem

#177

Post by huxley »

jacquesm wrote: post #156
namibj wrote: post #124

Earlier quoted context omitted.

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”

Re: Solar panels + cold = A potential problem

#179

Post by shepherdjerred »

syntaxing wrote: post #150
namibj wrote: post #134

Earlier quoted context omitted.

There's a reason people don't install electric equipment without training. This is just like not upsizing wire gauge if you have a bunch that are loaded simultaneously buried together in a somewhat insulating wall. Without the burying under plaster, everything would be fine. But combine that with simultaneous loading during summer, and you fry/roast the PVC insulation.

> There's a reason people don't install electric equipment without training. I’m not sure if I follow that logic and if your analogy follows. I would argue this is closer plugging in an appliance rather than running wires. If I run a 15A appliance on a 10A breaker, a normal person without training would expect the breaker to trip. This is like running a 10A appliance and the 15A breaker trips because the appliance is…

> If I run a 15A appliance on a 10A breaker, a normal person without training would expect the breaker to trip.

Would the breaker trip in this case? I thought in this case it'd be more likely to start a fire.

Edit: thinking about this more, I think I'm wrong. A fire would start if your wires were too thin for a given amperage. Breakers detect current flowing.

Re: Solar panels + cold = A potential problem

#180

Post by privatelypublic »

jama211 wrote: post #166
Aurornis wrote: post #122

Earlier quoted context omitted.

> They shouldn't be that close to the absolute maximum voltage ratings on the components. This appears to be a situation where the engineering team determined the absolute maximum input voltage and the marketing/product people put that number straight into the documentation. Standard practice with electronic parts is to determine the absolute maximum rating, then to specify a recommended maximum that allows for some…

One way or another, many of us are in agreement the company screwed up and it’s on them to fix it - whether that’s their marketing, their manual, their lack of over voltage protection, whatever it is it’s their fault. Yet so many people in this thread are so keen to blame the customer, it’s pure ego from them. “I’m too smart for that to happen, so it’s all their fault!” they sneer. Classic bad faith forum behaviour…

That's humanity in general. But yea- general guide says "add up your open circuit voltage and don't exceed that." If something fails because of the panel manages to get more than 1000W of solar flux, and is cold... it's the mfgr's problem.

I need to actually look up why the extra flux increases voltage. Maybe it really doesn't but just moves the MPP to a higher voltage by having more current.

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