Re: 6 Volt generator ?
3-5 watts is in the same range as a bottle gen. If your state requires something a long the lines of DOT lighting you could need as hight as 55watts in high beam alone. The coil in my Lifan engine supplies enought wattage to run a 55 watt H/L and a tail and brake light. If thats what is required probably a total loss battery system would be the easiest, at least it might get you certified.