Donna, my OEM battery was always maintained, and I was pleased with it. However, this very early spring (March), the FSU repeatedly discharged it, eventually killing it. It would not hold the charge anymore - explained by your Bentley blurb attached (it was NOT immediately recharged, because as you know the FSU works in mysterious ways when it fails. Sometimes it would start fans and whatnot, other times it would stay put. In the final stages of failure, the FSU will drain steady the battery aka keep fans on all the time and other stuff). After the damage was done, when I recharged my old battery the 3d and 4th time in 10 days or so, she would not hold the charge at all. Barely starting the car. However it lasted 7 years. I'm OK with it, as usually a battery would last 5 years if you're lucky (I know people have reported phenomenal 11 years of service life out of the OEM BMW battery - Varta- but maybe their FSU was replaced before it went kaputt?
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TMS underdrive pullies - Stewart WP - PSS9 - Beisan Vanos seals - Zimmerman cross-drilled & Akebono Euro - Deka 649 MF - 55w HID headlights - 35w HID foglights - Hualigan double din - ACS (rep) alu pedals - Euro central storage console - Breyton Magic Racing staggered wheels - M5 bumper - M5 steering wheel - Tint
Stable: e39 M54, e53 N62 & Tribby