Aaron - I think the EVs use a 150amp alternator.  Maybe a couple of them
in the rear of a Vanagon would suffice?

I'd suggest that you really do not need to keep all six units on, except
when those nasty Dudes/Dudettes heading your way refuse to dim their
hi-beams.  Then, turn them all on and blind the hell out 'em, at a
distance sufficient to assure you that they'll run off the road way
before you get to them.

BOB