[MLXXXp]

Originally Posted by Ken Maltby

OK, you got as far as Ohm's Law.

Nope, sorry. Ohm's Law deals with the relationship between resistance, voltage and current. I didn't use it at all. I only used the electrical power law (I don't think it's named after anyone since it's derived from Ohm's Law and Joule's first law).

The panels get hot from being in the sun, not from any undrawn power build up.

Now we need to get into the first law of thermodynamics.
http://en.wikipedia.org/wiki/First_l...thermodynamics

Light is a form of energy. When that light hits the panel, it is either reflected off the panel or absorbed and converted into some other form of energy. If the panel isn't connected to anything, then almost all the absorbed light is converted into heat (which is another form of energy).

However, if the panel is connected to an electrical load, then some of the absorbed light is converted into electrical energy, so given a constant amount of light, the panel will remain a small amount cooler. That electrical energy will be converted into heat by the load (or stored as chemical energy by a battery), thus satisfying the first law, requiring the conservation of energy.

The only reason that the panel heats up is because it's not 100% efficient in converting light to electricity (probably more like 10%) or the load is not capable of accepting all the electrical energy.

What do you think would happen if a solar panel could convert 100% of the light to electrical energy and that energy was completely supplied to an external resistive load? The answer is that the panel wouldn't heat up at all and remain at the surrounding temperature. (Though, the bezel would still heat up and possibly transfer some of that heat to the panel). The resistor would then heat up instead.

You know, I've found that it is useless to get into a discussion about theory when it comes to likely experimental results.

Well, I was right when I predicted that the 1.8W panel wouldn't be sufficient, before you tried it experimentally