The 12V battery replacement is a challenge

Hi,

When the 12V battery that operates the computers fails, the car throws a bunch of scary 'drivetrain' messages and can turn on the alarm. But the $277 replacement from BMW is too expensive. I found a local, $136 Deka, ETX18L that with razor knife and Dremel tool can have the positive terminal modified to work. BMW really over-engineered in a bad way the 12V battery.

Having done it once, I would trim off the offending metal part of the brass terminal fitting. This keeps the battery in original condition yet avoids the BMW 'lip'.

Bob Wilson

 

Here are the batteries side-by-side:




Here it tried to open the space on the substitute battery terminal:


Here is the original cable terminal. The fat part would not fit:


So with a Dremil tool:


View attachment 18924

Bob Wilson

 

Bob Wilson