Newer than 2006-7 will have IBS and will log a histogram of how charged the battery was over time.

When my customer's 2008 328xi started having problems starting and would lose the time of day regularly I pulled the histogram just before replacing and it was horrible.

20% charge 30-40% of the time 40% 40-50% of the time. Never made it to 80% in the previous xx months. It was seeing that graph on a car that started find and ran great other than a few times it took two presses of the start button to get going that gives me the conviction to say it just sounds like end of life on the battery.

You will find that many many things go haywire when voltage gets low.

You need to check the current draw on start to make sure it's not too high lest you kill a new battery. (happens often)

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2011 E70 • N55 (me)
2012 E70 • N63 (wife)