That may have been the case when car vacuums were plugged into the car’s cigarette lighter. However, all models on our list are either battery-operated or plug into wall outlets. Only one can even be charged via the car’s cigarette lighter (although that’s an alternative option, not the primary charging method)—and this should be fine for occasional use, assuming you don’t have a weak battery, parasitic drains, a defective alternator, or other vehicular problems.