Dead Battery and other problems

[Gonville]

Our guru here in the UK is suggesting that using ISTA is th e only reliable way to check the 12v battery health. That 5 years shouldn’t be th enormous but the battery should be tested. I have no idea what Adam it is using given that the perceived wisdom above is that the ‘alternator’ charging curve isn’t amended with age using th e registration date.

 

[Dutchi3]

I measured the battery just when I took it from the car: 12.7 volts. In a day it became 11.6 volts stabilizing at 11.5 volts a.k.a. empty

 

[fbt12]

I measured the battery just when I took it from the car: 12.7 volts. In a day it became 11.6 volts stabilizing at 11.5 volts a.k.a. empty

For those of us who don't have a 12v battery monitor. I strongly suggest that you replace your 12volt battery at the 4 year anniversary or even earlier (...battery will ordinarily last between 3 to 5 years, but that can vary greatly depending on type of battery, battery size, weather conditions and driving habits. Even still, just because your battery isn't entirely dead, doesn't mean it's operating correctly.). My 12v read fine when I would bring it in on regular oil change/brake fluid swap for the last 3 years. 2017 i3 meant the battery was 6+ years old. Unfortunately, it died soon after my last service (and battery test) and the cost to replace the battery AND re-set the onboard computer was close to $600.

Not much of a DIY'er so I rely on my non-BMW local service. Not a problem for maintenance stuff. However, for replacing battery and resetting my computer, I had to tow it to a BMW dealer. I would have save a $450 if I would have just replaced the battery sooner.

Expensive lesson.