According to the Japanese specifications PDF, one can expect to use 6.38kWh using 200V/16A (6.47kWh using 100V/6A standard Japanese household power). 6.38kWh closely matches our NA owners' measured wall power consumption (either 110V or 240V). In case anyone's curious about the official numbers.
You can't charge the Prime at anything over ~16 amps at 240v. The on-board charger is limited to just 3.3kW. But I wish I could. My charging circuit is 240v and 40a, with a eMotorWerks 40a EVSE. It is complete overkill for the Prime, but I wanted room to grow for another future car with a 6.6 or 7.2kW charger.
I've charged my Prime at just over 3.6kW (240V × 15A). I've never needed a fast charge at home, but out I have many times. A 6.6kW charger would be nice to have for sure for those situations where you are just sitting and watching your car charge (boring and time consuming).
