Hi guys

I have been noticing for over 3 months that my battery is not holding much charge.

What happens is if I turn my engine off and keep the interior lights on for even 2-3 minutes, I get a low battery sign on the iDrive.

When the car is completely locked, it can stay for over 3 days and be just fine. I just left it in an airport parking lot this weekend for 3 days and it started just fine later.

So I am not sure whats going on. Coincidentally, this all started with I installed a modmynav kit which I have now completely disconnected. I also keep no other electronics connected when I turn off. Last week in a crazy event, the car decided not to switch gears when I parked it in a lot (it was turning on but I couldn't switch from park to reverse or drive) and had to be towed to my dealer, who found the issue gone the next morning. The dealer monitored the car overnight for battery drain and didn't find anything.

I have read somewhere that the IBS sensor on these machines can be faulty too.

I am hoping someone has seen something similar before and can help. I now travel with an emergency jump starter, but would prefer to have this issue resolved.

My 08 5er did this too. After much persistence the dealer found the telecommunication module woke up, at about midnight, and began looking for a signal. It drained the battery. I do have a brand new BMW trickle charger, never opened, for this car if you are interested. Good luck.

Thanks juris, that could definitely be the case but the stealership didn't find anything after monitoring the car overnight. I am probably going to get the battery changed anyways sometime next month to see if that fixes it.