[cujet]

The 20 pound (really 15-17 pound) propane bottle will get quite cold running a 3500 watt genset. You may have problems sustaining rated power unless you run a larger tank.

I like your idea very much. A pilot I work with built a gem car with a Honda generator. He was able to extend his range enough to drive it to work. However, his 115V charger only ran on one leg of the 220V genset. So the generator/charger setup was not putting out anywhere near enough power to sustain the vehicle. Maybe 1500 watts total boost.

I wanted to work with him and build a simple charger and voltage regulator that would be much more effective. However, the generator was stolen right off the back of his car. My idea was simply to build a basic FWB and regulate the output according to need. The voltage of his battery pack was close enough to work, without massive difficulty or expensive equipment.