Originally Posted by yogi
go to autozone, buy a battery for 130 and change it yourself. thats what i did for my e90 and e60. no problems here.
From what I understand, though, the alternator adjusts how much voltage gets sent to the battery--so as the battery wears down, it will deliver more power to the battery on ignition. The usual dangers are explosion, fires, etc., but other people have not had issues. My main concern is the fit--the BMW battery is *huge* comparatively, and there's been some discussion about what battery is even supposed to be in there. Have you had any issues with yours? How long as it been in there? What kind of battery, etc.?