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Solar panels + cold = A potential problem

linspyre.com

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Re: Solar panels + cold = A potential problem

#101

Post by throw-qqqqq »

saghm wrote: post #42
syntaxing wrote: post #13

> 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…

Agreed. No one needs to change which type of gas they use because it happens to be a warm sunny day.

Yeah car analogies suck.

Diesel is blended differently for winter and summer in many countries. See this for instance https://www.crownoil.co.uk/guides/winter-blend-vs-summer-ble...

Around the skiing season, many automotive magazines will remind diesel drivers to buy “winter diesel” or use additives if e.g. driving up to the Alps or similar cold places.

It’s not so black and white :)

Re: Solar panels + cold = A potential problem

#102

Post by Jgrubb »

syntaxing wrote: post #13

> 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…

I love a good analogy. This is not a good analogy.

Re: Solar panels + cold = A potential problem

#103

Post by pfdietz »

gsf_emergency_2 wrote: post #70

To flip this into a potential solution to a wider problem-- global thermal balance-- combine solar panels with radiative cooling. https://www.sciencedirect.com/science/article/pii/S258900422... https://www.pv-magazine.com/2025/01/13/daytime-radiative-coo...

https://web.stanford.edu/group/fan/publication/Li_ACSPhotoni...

Re: Solar panels + cold = A potential problem

#104

Post by ninalanyon »

TeMPOraL wrote: post #80
abcd_f wrote: post #60

Earlier quoted context omitted.

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.

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 pse…

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.

Re: Solar panels + cold = A potential problem

#105

Post by jfengel »

Jgrubb wrote: post #102
syntaxing wrote: post #13

> 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…

I love a good analogy. This is not a good analogy.

I'm not sure I know what a good analogy looks like. If the two things are identical, then the analogy is uninformative. If they're at all different, you will zero in on the differences rather than the similarities.

Sometimes they can be ok pedagogical tools, but they're easily misused as tools of persuasion.

Re: Solar panels + cold = A potential problem

#106

Post by stephen_g »

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.

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

Re: Solar panels + cold = A potential problem

#107

Post by jfengel »

dotancohen wrote: post #71
saghm wrote: post #42

Earlier quoted context omitted.

Agreed. No one needs to change which type of gas they use because it happens to be a warm sunny day.

In the Corvette community, using a higher octane fuel on hotter days is well known to prevent ping.

I'm surprised the Vette doesn't call for high octane all the time. It's common for high compression engines.

Re: Solar panels + cold = A potential problem

#109

Post by bryanlarsen »

happosai wrote: post #100
saghm wrote: post #42

Earlier quoted context omitted.

Agreed. No one needs to change which type of gas they use because it happens to be a warm sunny day.

True for gas not for diesel. You have to switch to winter- or arctic diesel if the temperature goes below -20c.

Gasoline is also blended differently for summer or winter. It's not as crucial as for diesel, but it does make a significant difference.

Re: Solar panels + cold = A potential problem

#110

Post by sunshinesnacks »

uyzstvqs wrote: post #61
taneq wrote: post #47

Earlier quoted context omitted.

What does “maximum possible voltage” mean for a solar panel? Do you include things like cloud edge effect (which increases incident light beyond direct sunlight?) What about installs with a nearby window reflecting light onto the panel? Do you include ultra-cold environments (which will reduce the resistance and therefore often increase voltage, although admittedly not, I think, Voc)?

VoC is the maximum potential voltage a cell is physically capable of producing. It does not consider real-world conditions. Rather, real-world conditions cause the solar panel's output voltage to be somewhere between 0 and its VoC.

Voc is just the open circuit voltage measured at the terminals (plugs). “Nameplate” Voc is at standard test conditions (STC) of 1000 W/m^2, 25 deg C cell temperature, and a standard are mass/spectrum. The combo of 1000 W/m^2 and 25 C cell temp is not common in the real world in most climates, but still happens. Even relatively hot climates can have times in winter that exceed nameplate Voc if inverters turn off (making the panels go to open circuit).
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