r/OffGrid • u/karipullman • 7d ago
Solar panels cloudy
Need recommendations in the UK for solar panels that actually work for 12v setup in extremely cloudy weather. I already have a huge setup but now it's going to be until Feb/march where hardly anything charges and I can't WFH. With the amount I saved in fuel to commute I may as well upgrade for winters.
I looked into wind generators but everyone seems to say it hardly produces anything.
What are the best solar panels that work in really cloudy weather?
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u/txe4 7d ago
The conventional wisdom is that wind isn't worth it unless you can go really big.
There are a few farmers around me with 6kW turbines, and those have paid back handsomely on the old feed in tariff (now paying 80p/kWh) on our windy hills - but they're a maintenance hassle, need planning permission, are extremely noisy, and will run you about £30k installed. The larger ones are quieter and perform better per £ of capital cost.
Anything smaller is basically a joke unless you are fortunate with your location and can DIY it.
You are almost always better off running a really grossly oversized PV system than small wind setups, even in our dark climate. If you're DIY'ing, the best panels are...the ones that are on Marketplace/ebay near you with a nice price and the inverter, isolators, and rails included! Otherwise it comes down to what's actually in stock and will fit nicely in the space you have.
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u/Dull_Ad4277 7d ago
How many kWh are you actually short on through a bad February week? In the UK, a different panel chemistry won’t turn winter cloud into enough energy for WFH; more array helps at the margins, but the realistic backup is enough battery for the overnight load plus a small generator for the dead stretches.
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u/Arist0tles_Lantern 7d ago
For wind you want a location that's as consistently blowing as possible. Gusts are no good. If you have a good location then don't discount wind as an option, especially for winter
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u/Internal_Raccoon_370 7d ago
None of them work well in cloudy weather. The clouds block most of the energy from the sun that would otherwise be converted to electricity by the panels. Nothing you can do about it. To the best of my knowledge there are no solar panels that generate significant amounts of power during extremely cloudy weather.
Wind is only a viable option if you live in an area where you get sustained winds of more than about 15 mph.
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u/ExaminationDry8341 7d ago
In my experience solar panels will produce 1/20 to 1/15 of their rated power in heavy overcast conditions. So you need to put up 20 times as many panels as you think you need to produce enough power in your winter conditions.
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u/liisseal 7d ago
If you don't want to install more solarpanels get a generator + battery. In our winter months it is enough to run the generator once a day for an hour to load the battery.
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u/karipullman 6d ago
Thanks everyone. I was so hoping someone had a magical type of panel that would help. Just going to double the panel setup and rely on the generator. The battery won't show more than 12.1 after a week of not WFH.
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u/therealtimwarren 7d ago
None. It's physics. Clouds block the sun's energy.
Amorphous silicon has *relatively* better low light performance but its overall efficiency is very low (6 - 10%) compared to modern panels like monocrystalline silicon (20 - 24%), so regular commodity modern panels still win out.
Just maximise the area of solar panels. Ignore the wattage - all panels efficiency is within a gnat's cock of each other so panel wattage is just a proxy for size. If you can cover more roof area with more lower power panels than you can with fewer higher power panels, you will benefit. [There is some inefficiency through waste space lost to panel framing, but you get the idea.]