Dying 12V or something else?

[scottmetoyer]

I have a 2017 BEV with about 20k on the odometer.

Due to quarantine the car has been parked for 4 months with only 2-3 occasional short drives. I took it out today and a few minutes into the drive the climate control lights all turned off. Everything kept running fine, but no AC or fan lights, and I think the hazard light button may have turned off too. A few minutes later everything came back on.

I know I'm close to the 3 year danger zone for the 12 volt battery and figured that was it, but I'm also reading about issues with the climate LEDs blinking and shutting off. One thread mentioned some people have resoldered or replaced the LEDs on the climate control board, but I couldn't find anything further about that.

Does this sound like a 12v battery issue, or something else? Thanks!

 

[Anonymous]

2017 and 3 years is pretty early for 12v battery end-of-life issues. My 2015 with 20K miles is still running the original 12v (with a new one sitting on a shelf in the garage for replacement when needed). Very likely that the 12v battery's charge was just down from sitting for so long. The battery will charge up from the DC/DC converter when the car is 'active'. I would do a wait-and-watch to see if the symptoms persist.

There is a difference between a 12v battery with a low charge, and a failing battery that won't hold a charge. The former will charge back up and be fine, the latter will need to be replaced. To keep the battery charged when the car sits, use the BMW app to lock and unlock the doors every couple of days - 'waking up' the car like this will kick on the DC/DC converter and keep the 12v charged up from the HV battery pack. Or store the car plugged in with the car's charger (BMW's recommendation).