My old BMW 535xi used an H7 or optionally, an H8 battery. Not AGM yet, as my brother had a newer 528i XDrive that mandated the AGM, so I could still use a standard battery.
In my case, the battery still had the ability to crank the car over and run it, but it had a lot of electrical quirks and warnings going on… codes that countered each (low then high voltage), etc. i installed a NAPA The Legend battery in H8 size and that fixed all the problems. I didn’t yet have a code reader that would register the battery, so on my next service I asked the dealer to do it for me. They did it and had no issues or concerns over my non-BMW dealer supplied battery.
Car was sold with it still going. I’d change it and get a coder that can register the battery and save a ton of money.
In my case, the battery still had the ability to crank the car over and run it, but it had a lot of electrical quirks and warnings going on… codes that countered each (low then high voltage), etc. i installed a NAPA The Legend battery in H8 size and that fixed all the problems. I didn’t yet have a code reader that would register the battery, so on my next service I asked the dealer to do it for me. They did it and had no issues or concerns over my non-BMW dealer supplied battery.
Car was sold with it still going. I’d change it and get a coder that can register the battery and save a ton of money.