My car’s SOC varies between 70-90%, can run to almost 100% on long trips and often hangs around the low 70s when doing shorter trips around town. Ineos have advised me this is normal. That said I reckon not getting above 63% is not normal. The following post in another thread by
@NQ94 has a bmw document attachment which explains how the BMW BMS and smart alternator work. Worth a read.
https://www.theineosforum.com/threads/battery-charge-limitation.12415425/post-1333276455
Cheers
Steve
I see from the bmw doc, an AGM battery is expected...in a bmw
An IBS (intelligent battery sensor) is installed in
all cases.
A vehicle battery with AGM technology is
always used due to its higher cyclic stability.
The cyclic strength of the AGM battery is
three times higher.
The control process of the IGR or vehicles with
MSA (automatic engine start) makes such a
vehicle battery necessary.
3 The battery will age prematurely if a
"normal" battery is installed. 1
Deactivation of intelligent alternator
control
The intelligent alternator control is deactivated
under following conditions:
• Battery charge level too low
• Ambient temperature too low
• Deactivation in stages as soon as the AGM
battery has reached the maximum cyclic
stability
3 The intelligent alternator control must be
deactivated during an alternator test
conducted with the BMW diagnosis system.