Solar Panel Question.

[WelshGas]

What happens to the unused power/amps produced when the Leisure Battery is Full.

In bright sunlight my 100w Panel will show 20v and 0.1 amps or from the MPPT Controller about 14 v and 0.2 amps when the Leisure Batteries are full.

 

[Legin]

Presumably it goes open circuit so no load or a high resistance.

 

[marchugo]

Your unused amps escape into the air as heat.

Maybe bake an egg on your solar panel?

Regards from Amsterdam,

Marc.

 

[MattBW]

Some controllers turn the excess power into heat via a metal plate, my first solar setup MPPT controller did this (2013 though), and instructions said it had to be against metal bodywork.. Expect the Victron ones are a bit more sophisticated than that now?

 

[Roger Donoghue]

None of the MPPT chargers I sell get remotely warm. Victron and EPever.

The panels don't just get hotter - they'd melt very quickly!. I believe that when no load is demanded of them, they don't produce power! - at least that's what I've read. They are an open circuit by default (the panels), and if the MPPT controller doesn't need any more power, it leaves the circuit open - so no power is produced anyow.

Put it this way - when I put a new panel on the floor in the sun, with both wires, + & - , dangling in the air - it is 100% an open circuit - i.e. not a circuit! So no power is being generated and it certainly isn't "leaking" out of the cable ends. Much the same as a battery is an open circuit by default, and no power is generated until you close the circuit - plug something across it.

 

[Loz]

Don’t forget ohms law, without the load there is no current. Without the current there is no watts, without the watts there is no heat.

 

[Lightning]

The energy from the sun imparted on the solar panel is the same whether some of it is converted to current/ power or not. So the total energy dissipated by the system is unchanged, if no power is supplied by the panel all the energy imparted to the panel heats up and is dissipated by the panel itself.


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[Lightning]

The panels don't just get hotter - they'd melt very quickly!.

The panels re-radiate the heat, which is why they don’t melt. It’s only the same energy as light bulb that has to be dissipated.


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[mkbutters]

Will a 240 w panel run my fridge / heater?

 

[Lightning]

Will a 240 w panel run my fridge / heater?

Having asked this question myself it the past, apparently it’s sufficient for spring, summer and autumn in the U.K. but maybe not winter when there is little solar energy.

You may only need half that for summer.


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[Roger Donoghue]

100w or there abouts for summer - fridge, general camping.

Spring and Autumn benefit from 200w+ - particularly if you are using your fridge and also your heater (fuel burning heater - the fans use a fair chunk of power)

Winter - the solar is more of a maintenance charge, unless it's a nice clear bright day and you have the roof raised. Grey winter days give very little.