Originally Posted by mr_milo
My commute is driving 9.7 miles, about 21 minutes with a mix of city streets and freeway, each day to and from work (about 19.4 miles / 42 minutes a day total). I find it had to believe this isn't long enough since my Audi handled it without issue and my wife's commute in her Honda CRV is only an extra 1-2 miles. The CRV is a 2009 with it's original battery.
i bought my E90 330i in 2011 and i think it got its battery replaced before i took ownership. so my experience may not be representative of your experience. however, i DD my E90 and commute 10 miles round trip, city driving, approximately 10 to 15 min. no low battery issues.
maybe what you're experiencing is the battery cable recall? i've got an 06 and apparently, not part of the recall. http://www.e90post.com/forums/showthread.php?t=804545