I don't know whether the heat pump runs from 12v DC or 400v DC, but surely it doesn't run from AC, either 120v or 240v. Therefore the on-board charger has to be running during your preheat. That means the cooling system is also running, and the DC/DC converter is likely to be running to supply the 12v for the cooling system, if not also the heat pump. Both the charger and the DC/DC converter are water cooled, and the heat the coolant extracts goes to the outside of the car, not the cabin.Rauv wrote:I am making the assumption that after a full charge (8 hours+balancing) followed by a pre-heat, means that all of the load from the wall effectively goes to heating the cabin. Maybe that is not the case and the traction battery provides some energy to heat the cabin even while plugged in?
So you still have a number of variables for your test.