I have seen this mentoned in older threads, but a quick search for "new battery" and "replacement battery" did not identify the thread... so thought I would post a new thread with a clear title for others.
Last weekend the battery on my 2003 330i (two years since delivery) started slow cranking, so I decided to replace the battery. I remembered reading in a forum somewhere that Autozone Duralast 49-DL was a direct replacement.
Cruised down to the local Autozone and purchased 49-DL for $64.99 (the sales dude will tell you it is not in his computer and won't fit... but ignore him).
The install was simple and it fits perfectly. The battery even includes the rubber vent tube. You will need to trim about a quarter inch from the battery side of the rubber tube to get clearance for the hold-down bracket. Works great.
Hope this helps some fellow Bimmerfester's looking for a new battery.
P.S. Before someone asks.... I know the car warranty would have replaced the battery, but for $64.99 I did not want to take the day from work to mess with the dealer. Plus this is a higher CCA battery then OEM.
(I believe it actually contains a small explosive and is intended to disconnect power to the starter in the event of a major collision).
I refuse to believe that anyone believes that.
Battery Safety Terminal
The battery safety terminal (BST) will avoid short-circuiting of the high amperage starter circuit in an event of a collision. BST is actuated by the air bag control unit and uses a pyrotechnic charge to separate the starter cable from the battery in a crash. Other electrical systems, such as warning lights and cabin lighting, possess conventional protective mechanisms and remain connected to the battery. The single safety battery terminal adds to passive safety and reduces the threat of fire in the wake of a collision.
Apparently BMW not only believes it but touts it as a safety feature:
There's a bomb in your trunk!
Well I'm probably going to jinx it, but my 2001 M3 has never needed a battery to my knowledge. The unit it has is huge and appears to be bullet proof. However, I know batteries always have a life span, so I'm just on borrowed time I suppose.![]()