If I'm plugged into a low-power charger (e.g., 110V/12A adapter) and I turn on the heater, which I believe draws more power than that outlet can provide, will the car use as much power as the charger can provide and then draw the rest it needs from the battery, using both power sources at the same time? Or will it switch to drawing entirely from the battery? Or will it perhaps run the heater in a low-power mode? (I kinda doubt that...) Before you answer "of course it can draw from both", which is the intuitive answer, have you actually confirmed this? Power/charging circuitry is complex and things that seem like they should be easy aren't always.