Is there any difference between preheating the car while plugged in vs unplugged? In my experience the heating doesn’t run off of the wall power, it simply drains the battery. The battery doesn’t charge while heat is on. So if I want to leave with 90% and a warm car I need to actually charge to 92% and burn off 2% heating it. Being plugged in seems to make no difference. Is this the experience of others?