[Grease23]

These cars have a number of features that in my opinion seem to represent dubious benefits achieved from arguably needless engineering complications.

Which brings me to the intelligent battery sensor. Complications? Sure. An extra sensor cable, registering and (sometimes) coding during a battery change.

So what is the benefit of this?

For context, based on 50+ years of maintaining my own cars, I think a battery that lasts 5 to 6 years in a vehicle driven daily has had a good, long service life. (Given my driving habits, that would be 80 to 100K miles.) A failure at 4 years on a battery that has never been totally run down seems a bit disappointing. Obviously based on warranty lengths, manufacturers and retailers seem to think it pretty likely you'll get at least 36 months. On cars driven rarely but kept on a decent battery maintainer, longer life can be 9 or 10 years, as is the case with my MGB I drive about once or twice a month.

Which brings me to the question: What is the benefit of the IBS system? Is battery life on these E chassis noticeably longer than a typical battery in a non-IBS system? Or does the IBS enable the vehicle to provide notice of potential issues earlier? Or is there some other meaningful benefit?

[codeterrorist]

From my personal experience. My original battery on the 2011 3 series lasted me until 2019.
And that's with very minimal driving. By the time I replaced it, I only had 42,000Km on the car.

I coded a new batter for someone yesterday and his car was PRE-LCI with 240,000+Km
So I would say yeah, the IBS does prolong the battery life.