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BMW and battery registration

 
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edjack



Joined: 04 Feb 2002
Posts: 3887
Location: San Jose, CA

PostPosted: Wed Jun 10, 2009 10:33 pm    Post subject: BMW and battery registration Reply with quote

The Krauts are at it again: when you replace the battery, you must tell the car what it is, whether new, old, AGM, etc. A computer controls the alternator output, based on the battery type.

Cars with the MOST bus, including all iDrive-equipped cars, have this "feature". You need a compatible scan tool to register the battery.

If the battery is not registered, its life can be shortened, even to die in a year, since the alt will charge it as if it was an old battery, too agressively.

Madness!
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Ed BMW CCA member since 1987 (Nr. 62319).
'97 540i 6 speed Aspensilber over Aubergine interior.
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PJK



Joined: 14 Feb 2002
Posts: 1829
Location: Shingle Springs, CA

PostPosted: Mon Sep 07, 2009 1:08 am    Post subject: Reply with quote

Hi Ed,

This is remarkable. I knew that lead-acid batteries lost capacity as they age but I never relized that the proper float voltage was a function of age.

I had thought that the float voltage was pretty much the same for flooded electrolyte, starved electrolyte, or gelled cells. Are they still using lead-acid?

What is the AGM battery?

Phil
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edjack



Joined: 04 Feb 2002
Posts: 3887
Location: San Jose, CA

PostPosted: Mon Sep 07, 2009 7:51 am    Post subject: Reply with quote

Absorbent Glass Mat: http://en.wikipedia.org/wiki/Agm_battery

Think Optima.
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'97 540i 6 speed Aspensilber over Aubergine interior.
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PJK



Joined: 14 Feb 2002
Posts: 1829
Location: Shingle Springs, CA

PostPosted: Tue Sep 08, 2009 12:28 pm    Post subject: Reply with quote

Thanks Ed. I should have known that. I just knew them as starved electrolyte batteries.

Does Optima have any competition in this technology for automotive batteries? I have used Optima batteries for several years and love them but they seem to have become very pricey. I had some sort of intermittent leakage in my e36 which left my battery dead a couple of times. Starved batteries don't tolerate this. I am getting due for a battery but I get "sticker shock" at the price of a new Optima.

Phil

edjack wrote:
Absorbent Glass Mat: http://en.wikipedia.org/wiki/Agm_battery

Think Optima.
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edjack



Joined: 04 Feb 2002
Posts: 3887
Location: San Jose, CA

PostPosted: Tue Sep 08, 2009 8:49 pm    Post subject: Reply with quote

I have seen other brands, but none is cheap.

I've always had good luck with Delco batteries.
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