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5.7 hemi, charging over 14v, is this normal? #970591
04/10/11 06:00 PM
04/10/11 06:00 PM
Joined: Aug 2006
Posts: 1,349
warfordsburg, PA
dirt Offline OP
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dirt  Offline OP
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warfordsburg, PA
i have a 2003 5.7 hemi swaped into my daytona and using the hemi alternator with it. i noticed my volt meter reading around 14.5 V all of the time. it dosent seem to matter if its at idle or reved up. is this normal? i know the battery should be more than 12v normally but wasnt sure how much.

once in a while i see the gauge flicker for a few seconds to a lower voltage, somewhere around 12v then jump back to 14.5v , i am working on cleaning all of the cables now just incase that could have something to do with it.

Re: 5.7 hemi, charging over 14v, is this normal? [Re: dirt] #970592
04/10/11 06:06 PM
04/10/11 06:06 PM
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Oregon
hooziewhatsit Offline
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14.5v is the perfect charging voltage. Don't worry about anything until it sits over 15v for extended periods of time.

Just sitting there, not charging, the battery should read around 12.5v.


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Re: 5.7 hemi, charging over 14v, is this normal? [Re: hooziewhatsit] #970593
04/10/11 07:39 PM
04/10/11 07:39 PM
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ahy Offline
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14.5 volts is the upper end of "OK"... no immediate danger. If it stays there for many hours, battery life may be shortened.

Are you running the 5.7 with original computer or converted to carb? I believe the computer has sensing and adjustment logic to increase voltage to around 14.5 after a cold start and back off a little as the battery charges and warms. If running the factory setup try to get a service manual for the donor vehicle. There might be a sensor or something that needs hooked up and/or installed or it may be working just as intended. The low voltage excursions may also be the ECU's way of checking the batttery condition.

If you have converted to the 70's "flat pack" regulator, it should back voltage off to 13.x as the engine compartment warms.

Re: 5.7 hemi, charging over 14v, is this normal? [Re: dirt] #970594
04/10/11 07:51 PM
04/10/11 07:51 PM
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Lincoln Nebraska
RapidRobert Offline
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Lincoln Nebraska
Quote:

once in a while i see the gauge flicker for a few seconds to a lower voltage, somewhere around 12v then jump back to 14.5v ,


I'm not up on the new stuff but that behavior doesn't seem right and unless you have ALOT of accessories/add ons operating as said it seems too high to me


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Re: 5.7 hemi, charging over 14v, is this normal? [Re: RapidRobert] #970595
04/10/11 07:57 PM
04/10/11 07:57 PM
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PS... there are lots of places voltage can be measured. Lots of differrent tools to do it also. Results will vary. Have you measured at the battery with a known accurate multi-meter? Suggest you do that first and post the result. Measure post to post across the battery and also positive post to a clean engine ground.







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