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      09-06-2017, 04:46 PM   #6
houtan
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Drives: 2011 135i
Join Date: Jun 2013
Location: socal

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2011 135i  [9.85]
Quote:
Originally Posted by Dackelone View Post
I think you should load test your battery. To me it sounds like its bad. How old is it?

You should have over +13v with the engine running. Also use a VOM for AC(yep AC)voltage across the battery with the engine running. IF you see more than 1AC volt across the battery... your alternator is bad.

It could also be something with the Intelligent Battery Charging System. Can your scan tool code your battery?
Thanks Dack.

Battery is about 2.5 years old.

Per the logs, I am getting over 13v with the engine running, so I am assuming that is sufficient to determine the alternator is good. does that make sense?

I pulled the CAS.TRC file via ncsexpert last night, just to make sure the charge rate was correctly coded when the dealer replaced the battery 2.5 years ago. It is correct at 90AH since my is a 90AH lead acid battery.

What do you mean by code my battery? I can register via INPA or toolset32, but is that ok with an old battery?

I agree the battery may be bad, or maybe things were wonky because I didn't disconnect the negative terminal on the battery when I was working on the car.
Appreciate 0