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this post was submitted on 17 Mar 2026
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Asklemmy
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Nothing happens. All you have is voltage. No current. No power.
I think their question makes sense. The light is hitting the solar panel regardless of whether there's current flowing or not. Where does that light energy go?
As far as I know, it gets converted to heat in the panel and vented off, but maybe there's something else to it.
There's only so much voltage that will ever get created in each cell by exposure to light. Only so many electrons that get knocked free. Once that level is hit, nothing else happens that wouldn't also happen to a stone, or your skin. Electrical energy doesn't build up.
Yes, most likely the light is just converted to heat. But that's not special.
The critical part is that the electrons moving consumes energy from the incoming light, reducing the heat being generated while current is flowing. A disconnected solar panel will heat up a bit more than a connected one, but the difference in Watts per area is low enough the panel can just dissipate the extra unused heat to the surrounding air without any issues (unless you're in the desert, maybe it's possible they could overheat there, but this would likely be an issue even when generating power).
Modern solar panels are only about 20% efficient, so the panel would only heat up an extra 20% if disconnected in direct sun
It's not "special", but it is what they're asking
electric potential? is the solar circuit a giant capacitor with a stored charge then?
Maybe you could think of it that way, but I don't think PV cells store much charge, so they'd make pretty crappy capacitors.
This is a bit complicated, but basically, energy is power×time and power is intensity×tension. Now if you have too much power, because you can't affect the flow of time (sad), you either change tension or intensity. The easiest is to just lower intensity (or cut it out entirely). If you just open your circuit, your intensity falls to 0. So your power falls to 0 and everything is fine. Just like how when you stop a windmill rotating it doesn't produce any power.