[Coastali8]

I have a 2015 that is a occasional use weekend car. It’s always plugged in.
The 12v battery is maintained on charge from the traction battery when the car is plugged in.

The car has been plugged in consistently since new when it’s not being driven. The 20Ah, 7.1 kWh, 355v traction battery BMW says must have 5.2 kWh useable at full charge to be considered 100%.
My battery reports 5.4 kWh still after 6 years and delivers the normal 16-18 miles expected range.

I’m still on the original 12v battery. I’m thinking about changing it out soon just for a little preventative maintenance. I just hate the idea of having to buy a battery from the dealership and paying for installation and registration. A 12v battery should be something the car owner can replace without a visit to the BMW dealer.

I have the OBD interface and necessary app to register a new battery but I can’t purchase a proper replacement battery anyplace except from BMW. The closest match I can find is the Remy FT560 group 26R. I’m tempted to give it a try.