I spent a lot of time in the woods during my Boy Scout days and loved it. Nowadays, any camping for me would involve my 5500 watt generator set outside the camp with a 12 gauge extension cord run into camp. They are loud, but effective! I'm good with a Coleman camp stove and lantern, but you can't beat electricity for some things.
I like the solar charger idea. I also agree that charging an eGo battery here and there is not going to run down a good car battery. If it does, you needed a new one anyway.
An eGo charger draws 420ma (1/2 amp) at 5 volts from a USB source. A typical 4 cylinder starter draws from 130 to 150 amps from the battery when starting the engine (150,000ma). A V8 starter can draw 225 amps.