Replacing the battery on my 2013 Z4 E89

[andrewgoldin]

Hello Everyone,
I'm back from another overseas tour during which time the battery on my E89 died. I am in the process of replacing the battery ... can I get some tips on:

1. What is the tool I should use to loosen the battery release bolt?

2. Once I connect the battery, will I need to register the battery with the car? I don't have the computer I'll need for that...

Thanks!

[andrewgoldin]

OK, I may have answered my own questions:
1. Socket wrench (metric)
2. From the Owners Manual:
"After a battery replacement, have the battery registered on the vehicle by your service center to ensure that all comfort functions are fully available"

Does anyone have experience with either task?
Thanks...

[JamesAustin]

OK, I may have answered my own questions:
1. Socket wrench (metric)
2. From the Owners Manual:
"After a battery replacement, have the battery registered on the vehicle by your service center to ensure that all comfort functions are fully available"

Does anyone have experience with either task?

The way this was all explained to me is that late-model BMWs are basically computer networks with engine and drivetrain accessories in the case. Unlike most cars, which use the battery to start and the alternator to run (which is why most cars keep running if you disconnect the battery), BMWs are wired to depend on the battery all the time. They also draw a lot of power even when they're not running. (You've noticed that...)

In order to get as much out of the battery as possible, BMW's engine computers need to know all the details; what the battery's capacity is, whether it's a conventional or an Absorbed Glass Mat battery, and whether it's new. The computers use all this info to figure the best charging profile; how much voltage & current, over how long, to what charge level.

So, if your new battery is the same capacity and type as your old battery, there's little new info, so registration isn't that big a deal. (BMW charges brand new batteries more slowly for awhile to break them in, which is nice, but not absolutely essential.) If you've changed to/from an AGM battery, or gone to a higher/lower capacity, then the differences are greater and registration is more important.

Of course, while doing some web searching to keep myself from getting my foot too far into my mouth with this reply, I found a thread in which someone said his "buddy who works for a battery shop" told him the only purpose of battery registration was for BMW to do market research on how different batteries perform, and that there was an official BMW service bulletin saying so. This was followed by replies telling stories of things not working right until new batteries were registered.

As a practical matter it's not complicated to do and doesn't require especially exotic equipment; just something to connect to your OBD II port. If you bought your new battery from a local shop they ought to be able to do it for you. You might as well ask...

[andrewgoldin]

Good information. I bought the battery from the parts dept at my local BMW dealer (Alexandria/Arlington). I had hoped to avoid another trip to the dealer, but it looks like I'll have to go by regardless. I wonder how much that computer costs...
Thanks James

[JamesAustin]

Good information.

Thanks.

I wonder how much that computer costs...

Check out the Carly adapter & app combination from myCarly. Unlimited battery registration is available as an in-app purchase. I own one of the adapters but for various reasons haven't bought the non-demo version of the app yet.

Thanks James

You're welcome.