We know that most of the car's regular systems (screens, radio, amps, lights, etc.) run off of the 12v electrical system and that Tesla has had issues with reliability on the 12v battery due to it being undersized and/or defective, but has Tesla ever stated under what conditions the 12v battery is "maintained" or charged? For an ICE the battery is only charged when the engine is running because that is the sole source of energy for recharging it. In a Tesla there is a DC to DC converter that can charge the 12v system from the high voltage battery but when does this happen? I would think it would/could charge the 12v system under any one or a combination of the following: 1) When the car is "on" 2) When the car is plugged in 3) When the "accessory" is active (screen/climate/radio is on) 4) Anytime the vehicle system sees fit to charge it It seems important to know under what conditions the 12v system is maintained because the high voltage battery can charge the 12v battery, but the 12v battery is required to close the contactors that allow the high voltage pack to do it's thing. Seems like a sort of catch-22 from an engineering standpoint. I would assume it to be #4 since the vehicle can be left for a long time plugged in but off and still be functional after months.