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Alternator Over Charging

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Old Jul 19, 2009 | 09:36 PM
  #1  
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Alternator Over Charging

Hi Everyone,
I looked in past threads and found alot of alternators failing to charge but my problem is my alternator at idle charges fine but as I increase the rpms it will top out at around 17 volts @ 2000 rpm. Also, I am hoping this is related, my batteries will completly drain overnight if I leave them conected. Is my alternator faulty and causing both problems?

I have a 99 f-350 7.3l power stroke with 90 000miles on it.

thanks
 
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Old Jul 19, 2009 | 10:09 PM
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It is time for a new alt and a new set of batteries. With the alt over charging it is damaging the batteries also.
 
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Old Jul 19, 2009 | 10:17 PM
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Originally Posted by nivek
Hi Everyone,
I looked in past threads and found alot of alternators failing to charge but my problem is my alternator at idle charges fine but as I increase the rpms it will top out at around 17 volts @ 2000 rpm. Also, I am hoping this is related, my batteries will completly drain overnight if I leave them conected. Is my alternator faulty and causing both problems?

I have a 99 f-350 7.3l power stroke with 90 000miles on it.

thanks
How have you obtained your readings?

EDIT: You may have a short in your wiring causing all of this, or not. I hate electrical gremlins.
 
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Old Jul 20, 2009 | 12:04 AM
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I've been just reading the voltage gauge on the dash. As the rpm go up so does the gauge and I have to turn on everything electric to keep it at 17v or it will go higher.
 
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Old Jul 20, 2009 | 01:05 AM
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Originally Posted by megawatt00
It is time for a new alt and a new set of batteries. With the alt over charging it is damaging the batteries also.
Jim nailed it.
Those batteries are boiled because of the faulty alternator.
Replace them all and be done.
 
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Old Jul 20, 2009 | 01:18 AM
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Wont the alternator overcharge if you have a bad cell or battery. Tyring to over compensate for the decreased battery performance ???
 
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Old Jul 20, 2009 | 12:19 PM
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From: Westford, MA
Originally Posted by nivek
Hi Everyone,
I looked in past threads and found alot of alternators failing to charge but my problem is my alternator at idle charges fine but as I increase the rpms it will top out at around 17 volts @ 2000 rpm. Also, I am hoping this is related, my batteries will completly drain overnight if I leave them conected. Is my alternator faulty and causing both problems?

I have a 99 f-350 7.3l power stroke with 90 000miles on it.

thanks
Welcome to FTE. We offer brand new alternators not rebuilts like most parts stores offer.There's also no core charge.

Here's a link to the alternator section on our website.

Ford Truck Alternator
 
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Old Jul 21, 2009 | 11:13 PM
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Originally Posted by ChunderDownUnder
Wont the alternator overcharge if you have a bad cell or battery. Tyring to over compensate for the decreased battery performance ???
I've had batteries go bad on me and the alternator never charged at this voltage before
 
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