Low Battery in Winter with Infrequent Driving
My 2008 135i coupe, with only 22,000 miles, began to have a low battery problem last winter due to my infrequent driving patterns. I'm retired and we usually use my wife's car (a Toyota Venza), so my 135i gets infrequent use.
This winter the problem is even worse. The car has always started, but during cold periods (below 20° F) it has frequent clock resets and today the battery icon came on. The car will be five years old next May, so I guess I've gotten decent life from the battery. I'm going to try to nurse it through this winter with a Battery Tender Junior left over from my (younger!) motorcycle days, but I expect I'll have to replace it sometime during the coming year.
I've read the battery threads and I see it's going to be expensive if I go to the dealer, and I have to be very careful to get the right battery and have it coded/registered properly if I go to a non-dealer shop that works on BMWs.