since there is no driving/transportation forum anymore, i'm asking the gear heads and mechanical geniuses on this forum:

is there a car alternator that could charge up some 72volts relatively well?

i ask because i'm in the planing process for an electric motorcycle and i have to say that the range is what i would like to improve on. past projects all over the net have shown up to some 30km but would an alternator hooked to the engine work?

i haven't seen one on any electrical project though, so i was wondering if anyone here is knowledgeable with vehicle electricals like car stereos etc.