2001 Mercedes Benz C320 Battery

STEVE FOSTER

MEMBER
2001 MERCEDES BENZ C320
6 CYL
2WD
AUTOMATIC
140,000 MILES

My mechanic tells me the alternator is overcharging the battery with over 14 volts, causing the battery to go dead overnight.

Is the alternator the real problem or is something draining the battery?

Monday, June 15th, 2009 AT 1:40 PM

4 Replies

RASMATAZ

MECHANIC
75,992 POSTS

If its over 15.5 volts its ovecharging the battery and can explode.

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Monday, June 15th, 2009 AT 2:40 PM

STEVE FOSTER

MEMBER
3 POSTS

Thanks Rasmataz, I saw the mechanic test the battery with the engine running and it was about 14.3 volts. He said the "overcharging" was causing the battery to go dead overnight. I think there is some kind of drain on the battery.

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Tuesday, June 16th, 2009 AT 1:23 AM

RASMATAZ

MECHANIC
75,992 POSTS

To prove there's a battery drain do below

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Tuesday, June 16th, 2009 AT 3:24 AM

STEVE FOSTER

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3 POSTS

Thanks again, Mr Rasmataz. My mechanic finally figured out the drain on the battery. It was the seat control unit.A very expensive part at $480. And they don't make any aftermarket parts like this one so the dealer was the only option. Appreciate the help!

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Sunday, June 21st, 2009 AT 1:29 PM