Not charging sometimes
Thread Starter
Racer
Joined: Jan 2008
Posts: 299
Likes: 4
From: Surprise AZ
Not charging sometimes
Question about charging system. On a 66 put a volt meter across the battery and no charge, (car is running) showing 12 volts, then it starts to move little by little 12, 121/2,13, 14,15,16, then pegs at 16. Changed regulators same thing. Checked wiring looks good, voltage wear it's suppose to be. Took alternator to auto zone, said it was bad. Then took it to a rebuilt shop said it was good. Then sometimes it doesn't charge at all. Alternator is a #'s match, rebuilt about 13 yr's ago. I only have 800 miles on the motor in 13 yr's. Everything is like new. What's up.
Burning Brakes
Joined: Apr 2008
Posts: 1,222
Likes: 93
From: shelbyville West Michigan
how can you have no voltage at the battery? I think your meter is bad, or if you are using the free harbor freight giveaway meter, the test leads are notoriously poor quality and loose contact in the ends...try a different VOM.
Burning Brakes
Joined: Apr 2008
Posts: 1,222
Likes: 93
From: shelbyville West Michigan
Race Director
Joined: Apr 2009
Posts: 19,294
Likes: 2,753
From: Charlotte NC
With you voltage spiking to 16 volts has me concerned.....more than it not charging at all.
I know from the company that rebuild alternators for me in my town..I do know that the stud terminal where you attach the red wire with a nut to the back side of the alternator...they had told me a long time ago to be watchful when removing the nut so this stud does not rotate at all and if it does....not too much...because it can cause for issues internally inside the alternator due to what is connected to it.
I know you stated the wiring is OK....and if you have verified that your voltmeter is reading correctly. I have seen the strands of the wiring break internally inside the insulation can cause for issues...but I do not know if that has anything to do with your high voltage reading....if that is truly correct.
When you have it running...is your ammeter working???
That is all I got for you right now.
DUB
I know from the company that rebuild alternators for me in my town..I do know that the stud terminal where you attach the red wire with a nut to the back side of the alternator...they had told me a long time ago to be watchful when removing the nut so this stud does not rotate at all and if it does....not too much...because it can cause for issues internally inside the alternator due to what is connected to it.
I know you stated the wiring is OK....and if you have verified that your voltmeter is reading correctly. I have seen the strands of the wiring break internally inside the insulation can cause for issues...but I do not know if that has anything to do with your high voltage reading....if that is truly correct.
When you have it running...is your ammeter working???
That is all I got for you right now.
DUB
Race Director
Joined: Apr 2009
Posts: 19,294
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From: Charlotte NC
If the system is working properly...the ammeter ....while the engine is running should be on the (+) side.
With the ammeter staying in the center (neither + or -) when the engine is running. I would either have to possibly set up another gauge to verify that the ammeter is good or bad....and IF the alternator is actually charging to 16 volts...which as I wrote....I am more concerned about.
DUB
With the ammeter staying in the center (neither + or -) when the engine is running. I would either have to possibly set up another gauge to verify that the ammeter is good or bad....and IF the alternator is actually charging to 16 volts...which as I wrote....I am more concerned about.
DUB
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Burning Brakes
Joined: Apr 2008
Posts: 1,222
Likes: 93
From: shelbyville West Michigan
try doing a resistance test on the field wire from the alternator to the voltage regulator, you may have a bad wire, or bad connection, especially where it plugs into the alternator.
Safety Car
Joined: May 2006
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From: Shelton, Connecticut
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15-'16
Try using a jumper wire from the regulator case to engine ground to make sure it has the reference.
Last edited by jaki30; Mar 4, 2016 at 10:54 AM.
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