Why European cars are different
European cars tend to pack in electronics, run start-stop systems and move the battery out of the engine bay for weight balance, into the trunk floor, under a seat or behind a cowl panel. Many use AGM batteries in specific sizes, and most watch their battery closely through a battery management system.
That makes the job more than a swap. The battery has to match the car's specification, the install has to keep the electronics powered, and the new battery usually has to be registered so the car charges it correctly.
+ 01 By brand
What to expect
- BMW and MINI: usually AGM in the trunk, registration needed on most models
- Mercedes-Benz: AGM main battery, and some models also have a small auxiliary battery
- Audi and Volkswagen: AGM or EFB, often coding needed on start-stop models
- Volvo: AGM is common, with a battery monitor that should be reset
- Porsche: specific AGM batteries; some models carry the battery in the front trunk
+ 02 Auxiliary batteries
When the car has two
Some luxury models carry a second, smaller battery that backs up start-stop or electronic systems. A warning about an auxiliary battery malfunction usually means that small battery has failed, and it can be replaced on its own. The tech checks both batteries on cars that have them.
Questions about European car battery replacement
Do I have to go to the dealer for a BMW battery?
No. Any tech with the correct battery and a scan tool that supports the car can install and register it.
Why is my European car battery so expensive?
AGM batteries in the sizes European cars use cost more than standard batteries, and the install takes longer when the battery is in the trunk or under a seat. The price is quoted up front.
What is an auxiliary battery malfunction warning?
On Mercedes and some other models it usually means the small backup battery has failed. It's a common, quick replacement.