As an afterthought, while less practical, you could have 3 or 4 sub packs in a larger car. You could use 3 or 4 separate 120vAC cords to your car and charge each sub-pack from it's own circuit. Then you could charge an Escape size car in 4 hours. But who wants 4 cords? I know a few people wouldn't mind... I think the majority would....