Interesting quote from the realoem.com diagram of my car:
"A more powerful battery may be installed
during retrofitting operations.
Standard batteries can always be
replaced by AGM batteries with the same
specifications.
Following either type of replacement,
the vehicle registration process in
ISTA/P must be supplemented by a vehicle
coding procedure, which is carried out
as follows:
----------------------------------------
Read out battery size and registration
from onboard electrical system:
ISTA->Service functions->Body->Voltage
supply->Register_battery replacement->
Test plan"
There are also the types of batteries and their specs.
http://realoem.com/bmw/showparts.do?...99&hg=61&fg=30
EDIT: I just ordered the 21lb version and it's scheduled to arrive tomorrow. I hope it's correct.
http://www.hpashop.com/product.sc?productId=45
Oh man, now I'm bugging about how to register this. Anyone familiar with the registration process with the BT tool?