Registering and reprogramming AGM battery
 

Need to replace the AGM battery in my 08 e70 X5 4.8i (built 04/08).

Does anyone have any experience with doing it yourself? I am not talking about taking the car to the stealer and letting them do the registering and programming (stealer quoted $581 for complete job) .... I am talking about buying an aftermarket equivalent such as a DEKA 9AGM49 (list $159.99) and using a free software like BimmerSoftware and the appropriate cable (about $40 on Amazon or Ebay) to register the battery and reprogram the computer to set the alternator amp output to the correct Amp-hour rating of the new battery?

Yes, you can do it quite simply using inpa. See this post

DIY - Register new battery - BMW 3-Series (E90 E92) Forum - E90Post.com

OK, I've seen references to INPA. What exactly is it, how does it work and what hardware/software is needed and where can you get it? Does this register the battery only, or does it also allow you to reprogram the Ah for a different spec battery?

Thanks!

Inpa is part of Standard tools. It includes NCSExpert and INPA. You need to use NCSExpert to change the type of battery if you are not just swapping the same one. Then you use INPA to do the registration <edit> It seems the newer cars need tool32 which is also included. A good resource to start learning would be bmwcoding.com. There is a wiki for beginners, start reading there.

You will need an Inpa compatible cable. I bought mine on ebay for around $50 if I remember correctly. You will need to search for the software, and then you will need the daten files which correspond to the version your car is on. The reason why the dealer is charging so much is that it probably includes bringing all the modules in your car up to the latest version of software.

Thanks. I'm on it!

would indy shops be able to do it for cheaper? I assume they'd have programming capabilities too? If it's something like $300 it may still be worthwhile.