[BADBIMMER6623]

Is there any special requirement when replacing a dead battery?

[sspade]

Yes, you need to make sure its AGM with the correct Ampere-hour rating.... and then program it to the vehicle.

Looking from a different angle:

No, you cant just select any battery and toss it in. Very sensitive electronics system at play and needs to be treated as such.

[Billfitz]

The battery must be registered, otherwise the car will over charge it. Many code readers will do it, as will BimmerLink. If the new battery isn't the same Ah rating as the old that may have to be coded. If in doubt google 'BMW battery replacement', you'll find many youtube videos on the subject.

[mig2830]

It is quit easy with ISTA. If the Ah is not the same as the old but higher, the car will calculate the new Ah rating as ISTA is telling the car to do so.