Good question and I don't know the answer, but I would assume it only charges when the car is on. It would be sweet if it topped up and maintained the 12v battery whenever the car is plugged in to charge the high voltage battery. Maybe it does? Someone with access to the service manual could find out.How is the 12v battery maintained under normal operating conditions ? Is the main battery always connected or only when the car is 'ON' ?
Everything but the drive motor is 12V DC (radio, instruments, power windows, lights, etc.).I was wondering the same thing. What is the 12v battery used for, anyway? Things like "legacy" equipment shared with other GM vehicles like fans, AC compressors, lighting, etc.?
The normal operation of vehicles with high voltage battery packs is for the battery pack to be disconnected from the rest of the car by a power relay when the car is turned off. This is to eliminate any possibility of people electrocuting themselves when working under the hood, for example.How is the 12v battery maintained under normal operating conditions ? Is the main battery always connected or only when the car is 'ON' ?
If you keep the car plugged into the portable EVSE or an L2 240V EVSE it will keep the 12V battery charged. No need to turn on the car every couple of weeks or so.Thanks for all the answers. It would appear that turning the car ON every other week for 20-30 minutes would keep the 12volt battery charged ?
If it won't be driven for 4+ weeks, GM recommends hooking up a trickle charger (along with having the high voltage battery at 2-3 bars).Thanks for all the answers. It would appear that turning the car ON every other week for 20-30 minutes would keep the 12volt battery charged ?
The manual states that if you are not going to be using the car for up to 4 weeks to leave it plugged into the EVSE so that the car can automatically run the battery TMS as necessary. Certainly not charging to 100% is a good idea. If you are going to park the car for more than 4 weeks, then you are supposed to drain the main battery down to 3 or 4 bars (15 to 20 percent), and hook up a trickle charger to the 12-Volt battery.As regards leaving it plugged in - my understanding of charging Li batteries (I also own a Tesla) is they like to stay within a range of 20 percent to 80 percent charged for longest life. If you charge to a higher percentage then you should use the car to 'drain off' some of the charge. If all that is correct then might leaving it attached to my charger (Juice Box) leave it fully charged for a long(ish) period ? I do not know what the parasitic drain is on the 12volt battery but assuming it is like ICE cars then it would likely go flat in about a month or so if it were not charged - hence the idea to turn on the car every other week for a little while.
What is your source for this statement? (I'm not saying you are wrong, I just want to know where you got the info.)If you keep the car plugged into the portable EVSE or an L2 240V EVSE it will keep the 12V battery charged.
But NOT charging when the HVB is fully charged and the vehicle is plugged into an EVSE?The 12 volt chassis battery is charged while the vehicle is in run mode as well as while the HVB is charging.