Originally Posted by lukester
I'm running a 55Ah Battery in my e92 M3. That was the smallest capacity which could be programmed into the battery management system by BMW.
Works without any problems.
I just get the battery weak message from time to time.
But that's because I don't use the car as a daily driver - mostly just for tracking.
So the car sometimes sits 2-4 weeks around in the garage.
If you'll use it as a daily driver you will not get the message as the battery will be charged regularly.
But even in my case. Never had the situation where I couldn't start the car anymore.
The battery monitor which throws the message is very sensitive.
So even if you get the message you'll be able to start the car 5-6 times before it's really to weak.
In my opinion this is a nobrainer if you're looking to save some lbs.
But don't just change the battery. Get a cheap 55Ah from an Autoparts store and then let BMW code the new capacity into the energy management system.
55Ah fit's without any custom bracket directly into the existing holes.
You are saying that we have to take the car to the bmw dealership to code the new battery into the management system?