I wanted to create a thread to discuss the various modes the car may be in and what the batteries are doing during these modes. There are 2 batteries - the traction battery and the 12v battery and it is somewhat of a mystery what is happening to them in the various modes the car can be in so I'm starting this thread to try to nail this down. Here are the mode I can identify and what I think is happening to the batteries: 1) Car off - The mode when the car is off and locked and not plugged in. Traction battery - slowly discharging (I've seen reports of about 1% per day). 12v battery - ? slowly discharging - I know that the 12v is required to turn the car on so I'm guessing that it is slowly discharging during this mode. 2) Acc Mode - There are two ways I've seen that the car can get into this mode - 1) unlock the car and sit in the driver's seat with the key fob but don't press the brake pedal. 2) Park the car and remain in the car in the driver's seat and after a while the car will turn "off" but still be in acc mode. In this mode the radio, HVAC, screen, and seat heater still work. One question is how long the car will stay in this mode as long as you are still in the car - my guess is indefinitely. Traction battery - discharging (this is needed to run the HVAC and other functions), 12v battery - ? I don't really know what is happening to the 12v battery here. I'm hoping that it is not discharging, but I'm not sure. 3) Drive Mode - The car is on and you are able to drive. Traction battery discharging. 12v battery charging? I'm assuming that this is one of the mode when the 12v battery charges, but I'm not sure. 4) Car charging - The car is plugged in and is charging. Traction battery charging. 12v battery charging? Don't know for sure what the 12v is doing here as well but I'm guessing that it is charging. 5) Charging finished - The car is plugged in and has finished its charge. After the car has finished a charge, it seems to go into car off mode and never goes back to charging mode but I'm not sure. I'm guessing here that the batteries are doing the same as car off where both batteries are slowly discharging, but I'm not sure. Again, these are my guesses as to what is happening and I'd love some input from others who have more definitive answers. As we have seen from other threads, the 12v battery is critical to get the car to unlock and turn on. I really want to get a good handle as to what causes the 12v to discharge and charge.