I think it's right that it is unlikely, if not impossible to put 500 miles of driving energy into the "battery" in five minutes of household current. I think the math gets a bit off track in the calculation of the energy consumption for gasoline vehicles. First, you don't always use all, or even half, of the available horsepower. Much less when driving at a steady speed. Second, even then, a lot of the energy produced is wasted heat (dumped by the radiator) and going out the tailpipe. Electric cars don't have these losses.

Perhaps someone has better data to put into the math.

I'll believe the corporate "hype" when I see it in production.