Originally Posted by Bartman619
battery may need to be registered because it's not charging properly. the original battery was an AGM type and needed to be set up correctly with the ECU. you said you bought the battery at autozone, which leads me to think that the battery was non AGM and not registered. it's ok that its non AGM, but not getting the battery registered poses several problems. the ECU thinks that the new battery is the old one, and may be charging it to a different amperage and maybe not enough to keep its cold cranking amps. if you can find an independent BMW garage which can register your battery, it will be way cheaper than doing it at the dealer.
AGMs only come standard on M cars. They can be retrofitted at the DEALER but non-M cars never come from the factory with AGMs.
OP, why did you get your battery replaced? Did you get voltage warnings? Did any convenience features (Comfort Access, Heated seats, defroster, etc) stop working?
If so, you need to have your battery registered to your car, provided you replaced the battery with the same Ah and Type, non-AGM (or AGM if it was previously retrofitted).
Our cars do not charge our batteries until the car has been warmed up and RPMs are held above 1500rpms. So short distance driving will kill your battery and you need to get a tender to maintain it. Or retrofit an AGM which is less prone to damage from a complete discharge. A lead acid battery will corrode with low voltage and decrease capacity.
If you bought the wrong battery and cannot return it, you need to have it programmed to your car. Options are 46Ah, 50Ah, 60Ah, 70Ah, 80Ah, and 90Ah, lead acid. 70, 80, and 90Ah, AGM.
After programming, the battery needs to be registered.