It would be interesting to compare notes as to your build date. Mine was early July 2009 and at 3 years old and 20K on the clock started exhibiting issues. Bottom line, the dealership replaced my battery under warranty, but cautioned me with regard to:
1) locking the car every single time I get out of it
2) trying to minimize times the driver's door is opened and closed without starting the car
3) getting it out on the road more for longer drives.
Considering the expense and aggravation of replacing the batteries in these cars, I opted for also getting a CTEK battery tender.
I am like you in that I have a short (5.4 mile) commute, often times done in about 10 minutes. The car barely gets warmed up. Plus, my weekly maintenance routine dictates that doors get opened and closed a lot and let's be real, firing up the engine and driving the car out of the garage then shutting it off is not really going to get the alternator spinning.
Since I received the new battery and acquired the CTEK unit, I've used it twice (in 4 weeks). It takes roughly 1-1.25 hours to bring my battery back up to fully charged. Now that I know the vagaries of the system, this is a small price to pay for peace of mind.
If your sport doesn't put blood, dirt or grease under your fingernails,
then it's just a game.
Euro Modded|Split Armrest|Rear Foglight Mod|BMW Performance Exhaust|CDV Delete|Shark Fin Antenna Delete|Front Reflector Delete|LUX H8 Angel Eyes|No Bells|Few Whistles|Das Fahren im Freien| BMWCCA#445793