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      04-16-2024, 10:25 AM   #32
Helmsman
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Drives: 2011 AW E90 M3 ZCP
Join Date: Mar 2014
Location: Stockholm, Sweden

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Quote:
Originally Posted by Redd View Post
Mine has been fine aside from the initial period of low voltage. Consistent 13.8-13.9V while driving now. Like u said, I think the new battery registration does more than we realize.
Meeting again on good old subjects Eric....

Replaced my battery (to a 95Ah AGM from an 80Ah acid that went crap in less than 2y...).

Measuring with Carly (an area where Protool do nothing) turns out that the alternator turns down the voltage output and subsequently the current. Not below 12V as in your case but 12.1-12.3, assumingly where a new battery would be with some load without alternator support. It seems to vary the output so occassionaly well over 14V to suddently drop again.
Previous battery always run with a good 14-14.6V.

Found some BMW pwr mgmt stuff that state that the various consumers should use the alternator output as long as possible, to only when not enought start to consume from the battery. Seems the other way around in your and mine case...always something going on with these cars...

So how did it continue in your case, voltage gradually came up and all fine?

Did you test the alternator yourself or handed it in?

Thanks
Nik

Ps. Adding mentioned desciption.
Attached Images
File Type: pdf 03_Power Management.pdf (1.07 MB, 43 views)

Last edited by Helmsman; 04-18-2024 at 07:56 AM..
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