Solar question-help needed

[hierony]

The more current you draw, the hotter the converter will get--basically all the excess power gets converted to heat. Ie, (12 V-5 V)* amps = watts

heating

. Milliamp draws aren't going to heat things up much (7 V * .250 A = 1.75 watts heat).

As for wire, you can get some pretty good speaker wire for much cheaper than much of anything else. Like $22 for 250 ft of 16 ga (ebay), or even 12 ga. It's pretty flexible, has ground marked on one side, and will take most of the light and some of the moderate currents.