[srbarnes4ever]

Bought my used 07 E90 in May 2014 with 65k miles. A week ago I clipped 95k miles and battery died. I had the white top, lead acid battery. Took it to my local Indy and they called back to tell me it was coded for AGM, much to my surprise. Given some of the threads around this, any comments as to how it lasted at least 2 years and 30k miles coded incorrectly? Just wondering....it has a new lead acid and coding was corrected.

[Welcome to NBA Jam]

Sounds about right. It had an incorrect charging map, so the battery life was vastly decreased. You should get at least 5 years out of your new battery.

[wallacelau]

Originally Posted by Welcome to NBA Jam

Sounds about right. It had an incorrect charging map, so the battery life was vastly decreased. You should get at least 5 years out of your new battery.

+1

[Wilt]

AGMs can take higher charging current rate. Too high a rate into your flooded battery can hurt because heat in battery causes IBS to cut back charge.

Automotive charging systems for flooded lead acid often have a fixed float voltage setting of 14.40V (2.40V/cell); a direct replacement with a sealed AGM unit could overcharge the battery on a long drive.

For AGM, the float charge should be reduced to between 2.25 and 2.30V/cell (summer temperatures may require lower voltages). So your flooded battery was not getting properly charged due to the management unit thinking it was AGM.