Buy a car, get a charger free...

The Great Short Circuit Giveaway :-)

And how many amps are these 240 volt chargers? What size "double" circuit breaker is required?

If you are nuts enough to buy one, I would be more concerned about the battery warranty. And the fine print, like how much charge does it loose before it is considered spent/defective?

For laptops, after 1 year the vendor considers 10 minutes as good. And will not replace it as it is considered a consumable there after.

And at 400 lbs, they will not be cheap.

If 240 volts, most people will have to get their garage re-wired. With axes, bet the first full month of Volt is a shocking experience.