[JimD]

There is absolutely nothing special about a battery from the dealer other than it will fit and be the right amp hours for the car. If you use NCS Expert you can see what our car has by reviewing the setting. The rating BMW uses is not something advertised for batteries in the US but it can be calculated from the reserve rating. If you are willing to do a little work you can save a bunch of money.

My battery is still working fine on my 2009. I've never used a trickle charger on it and it is only driven 2-3 days a week. I think the BMW charging setup is helping the battery last. So I will use a stock size replacement and code. I will use NCS Expert if I can find my cable and buy Carly if I can't. Even buying Carly will cost less than having a dealer do it. But if you want a simple no hassle way to replace a battery and are not worried about paying a bit more, the dealer is a reasonable way to go. But for those of us with the ability and inclination to save money, this is an easy way to do it.