No It needs the same power, but the current does the heating. The voltage drops quite a bit on the move, with the solar panel the voltage stays 1 - 1.5 volts higher than it did when running without it. So correspondingly the current is lower.
Remenber P=I*V in a DC system, but Heat generation is governed by P=I^2*R, so as the Current increases so does heat generation. Therfore if the voltage is higher, then heat generation in the windings is lower for the same power as it needs less current. As I can see figures on my meters on my C5 rather than the LED bars of the original I can confirm I'm pulling less current out on a run on a sunny day than before due to the higher voltage seen in the system.
I've not noticed any change in speed or difficulty pedaling since fitting the panel, but it is pretty thin at 2.5mm, with a lightweight 10*15mm angle section Aluminum for support. I don't think it's adding much more drag, but I am operating on a 12V system, and don't go above 15mph too often, just down hill when I'm braking anyway. You might notice it on a 24V model.
I've not seen any foil solar panels, but there are roll up ones but they run at high voltage for use on roofs for domestic supplies. Your best bet at the moment is to go for the lightweight flexible ones and make a lid for your trailer with them.
posted on: 08/04/2015 08:58:00