Charging Problem
Thread Starter
Melting Slicks
Joined: Jul 2006
Posts: 2,346
Likes: 41
From: Toronto
Charging Problem
Here is my situation-
65, recently restored
All new wiring with Lectric Limited wiring.
New battery fully charged
I rebuilt the alternator during the resto process and had it tested at that time and was fine(probably a couple of years ago...)
The ammeter gauge shows a small discharge when the car is fast idling(cold engine)
If I rev it up it goes to just a bit positive...turn on headlights goes way down to discharge.
If I drive for a while, then try to restart the battery is dead.
Obviously the batter is not charging properly, and the gauge is correct.
Been reading lots of posts about charging but not sure where to start to troubleshoot.
I did change the pulley on the alternator to get the belt to line up with the water pump. Could the size of the alternator pulley be the problem?
Or the voltage regulator?
Thanks
65, recently restored
All new wiring with Lectric Limited wiring.
New battery fully charged
I rebuilt the alternator during the resto process and had it tested at that time and was fine(probably a couple of years ago...)
The ammeter gauge shows a small discharge when the car is fast idling(cold engine)
If I rev it up it goes to just a bit positive...turn on headlights goes way down to discharge.
If I drive for a while, then try to restart the battery is dead.
Obviously the batter is not charging properly, and the gauge is correct.
Been reading lots of posts about charging but not sure where to start to troubleshoot.
I did change the pulley on the alternator to get the belt to line up with the water pump. Could the size of the alternator pulley be the problem?
Or the voltage regulator?
Thanks
Le Mans Master
Joined: Nov 2003
Posts: 5,772
Likes: 694
From: Maryland
St. Jude Donor '05, '09, '15
I would use a volt meter and read the battery static charge with the engine off. Then start the engine and see how much charge you get at idle and when you rev it up. I would not rely on the amp gauge when you are diagnosing a possible problem.
Le Mans Master
Joined: Feb 2008
Posts: 5,214
Likes: 447
From: NJ Hockey beer league
Hook up a volt meter and you will likely proove you have a bad Voltage regulator since you say you rebuilt and tested the Alternator already. Go with a solid state replacement for added reliability. 
Pilot Dan
Pilot Dan
Thread Starter
Melting Slicks
Joined: Jul 2006
Posts: 2,346
Likes: 41
From: Toronto
So let me make sure I have this right-
With the car off I read the voltage at the battery terminals...should be just over 12V
Then start the car and the reading should go up to over 14 indicating charging.
Sound right?
With the car off I read the voltage at the battery terminals...should be just over 12V
Then start the car and the reading should go up to over 14 indicating charging.
Sound right?
Le Mans Master
Joined: Apr 2006
Posts: 5,347
Likes: 36
From: San Clemente CA
Thread Starter
Melting Slicks
Joined: Jul 2006
Posts: 2,346
Likes: 41
From: Toronto
Great.
Will do that tomorrow and post the results.
If I want to change to a solid state regulator, where do you buy them and do they have the same wiring as the original?
Will do that tomorrow and post the results.
If I want to change to a solid state regulator, where do you buy them and do they have the same wiring as the original?
Last edited by hzz; Mar 16, 2012 at 11:18 PM.
Le Mans Master
Joined: Dec 2007
Posts: 8,000
Likes: 659
From: Puget Sound
You can add your old cover if you want it to look stock.
Jim
Le Mans Master
Joined: Apr 2000
Posts: 5,104
Likes: 1,362
From: New York New York
2024 C1 of the Year Finalist - Unmodified
2024 C2 of the Year Finalist - Unmodified
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2023 C1 of the Year Finalist - Unmodified
Here is an article I wrote discribing testing and operation of your charging system.
Joe
http://temp.corvetteforum.net/classi...ternator.shtml
Joe
http://temp.corvetteforum.net/classi...ternator.shtml
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Drifting
Joined: Jun 2005
Posts: 1,974
Likes: 2
From: Crownsville Md.
It seems likely it's the VR. But here is a problem I had, check the wiring
harness plug that goes to the VR my new harness from M&H was wired wrong. If you look in the first pic the orange wire is on top and brown and white under it and the second the brown and white is on top the way it should be. I was having the same problem as you. Shemp
harness plug that goes to the VR my new harness from M&H was wired wrong. If you look in the first pic the orange wire is on top and brown and white under it and the second the brown and white is on top the way it should be. I was having the same problem as you. Shemp
Le Mans Master
Joined: Feb 2006
Posts: 5,073
Likes: 414
From: Maine
I switched
Plug and play - http://www.autozone.com/autozone/par...30005_0_11092_
You can add your old cover if you want it to look stock.
Jim
You can add your old cover if you want it to look stock.
Jim
You just pry off cover, it is held on with glue. Take AC cover off old VR and put on top of new VR. Mark holes, drill small hole, put old cover on , screw down, and you are set.
Charges at idle, no flicker or dim lights at idle, charges battery perfectly.
The best electrical change you can make.
Jack
Thread Starter
Melting Slicks
Joined: Jul 2006
Posts: 2,346
Likes: 41
From: Toronto
Here are my findings so far:
Battery with car off: 12.66 volts
Battery with car on: lower than that...anywhere from 9-12 volts, fluctuating with RPM
At regulator terminal-
Battery voltage at number 3 terminal
6 volts at number 2 terminal...should be 0
key on...voltage at number 4 terminal
At this point I am suspecting the alternator...voltage at terminal 2 is not 0 as it should be....leaking diode?
Going to see if I can borrow a regulator that is known good from a friend and see what that does, but I am leaning toward the alternator, even though it checked out OK previously.
Any thoughts?
Battery with car off: 12.66 volts
Battery with car on: lower than that...anywhere from 9-12 volts, fluctuating with RPM
At regulator terminal-
Battery voltage at number 3 terminal
6 volts at number 2 terminal...should be 0
key on...voltage at number 4 terminal
At this point I am suspecting the alternator...voltage at terminal 2 is not 0 as it should be....leaking diode?
Going to see if I can borrow a regulator that is known good from a friend and see what that does, but I am leaning toward the alternator, even though it checked out OK previously.
Any thoughts?
Last edited by hzz; Mar 17, 2012 at 08:06 PM. Reason: correction
Le Mans Master
Joined: Apr 2000
Posts: 5,104
Likes: 1,362
From: New York New York
2024 C1 of the Year Finalist - Unmodified
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2023 C1 of the Year Finalist - Unmodified
Here are my findings so far:
Battery with car off: 12.66 volts
Battery with car on: lower than that...anywhere from 9-12 volts, fluctuating with RPM
At regulator terminal-
Battery voltage at number 3 terminal
6 volts at number 2 terminal...should be 0
key on...voltage at number 4 terminalAt this point I am suspecting the alternator...voltage at terminal 4 is not 0 as it should be....leaking diode?
Any thoughts?
Battery with car off: 12.66 volts
Battery with car on: lower than that...anywhere from 9-12 volts, fluctuating with RPM
At regulator terminal-
Battery voltage at number 3 terminal
6 volts at number 2 terminal...should be 0
key on...voltage at number 4 terminalAt this point I am suspecting the alternator...voltage at terminal 4 is not 0 as it should be....leaking diode?
Any thoughts?
Battery voltage at number 3 terminal
6 volts at number 2 terminal...should be 0
Is this with the key on or off and is the plug disconnected?
Did you print my article and use it to check you system?
...voltage at terminal 4 is not 0 as it should be....leaking diode?
With the key on this should be battery voltage.
Thread Starter
Melting Slicks
Joined: Jul 2006
Posts: 2,346
Likes: 41
From: Toronto
At regulator terminal-
Battery voltage at number 3 terminal
6 volts at number 2 terminal...should be 0
Is this with the key on or off and is the plug disconnected?
Did you print my article and use it to check you system?
...voltage at terminal 4 is not 0 as it should be....leaking diode?
With the key on this should be battery voltage.
Battery voltage at number 3 terminal
6 volts at number 2 terminal...should be 0
Is this with the key on or off and is the plug disconnected?
Did you print my article and use it to check you system?
...voltage at terminal 4 is not 0 as it should be....leaking diode?
With the key on this should be battery voltage.
With the key off, and the plug disconnected, I get 6 volts at number 2 terminal on the regulator plug
If I understood the article, this should read 0 and indicates a leaking diode.
Am I correct?
I just saw my post where I said voltage at terminal 4 was not 0...I corrected it...voltage at terminal 2 was not zero,as it should be with key off and plug disconnected
Last edited by hzz; Mar 17, 2012 at 08:07 PM. Reason: additional info
Melting Slicks
Joined: Feb 2007
Posts: 2,937
Likes: 163
From: OP Kansas
C2 of Year Finalist (appearance mods) 2019
I had a problem with my batt going dead after it sat overnight. I had the alt tested and I was told it was OK.
I couldn't find anything wrong, but the batt still went dead. I had the alt tested again at a different place and it had bad diodes. Replaced the alt and never had the problem again.
I guess some places are better at testing than others.
I couldn't find anything wrong, but the batt still went dead. I had the alt tested again at a different place and it had bad diodes. Replaced the alt and never had the problem again.
I guess some places are better at testing than others.
Thread Starter
Melting Slicks
Joined: Jul 2006
Posts: 2,346
Likes: 41
From: Toronto
I had a problem with my batt going dead after it sat overnight. I had the alt tested and I was told it was OK.
I couldn't find anything wrong, but the batt still went dead. I had the alt tested again at a different place and it had bad diodes. Replaced the alt and never had the problem again.
I guess some places are better at testing than others.
I couldn't find anything wrong, but the batt still went dead. I had the alt tested again at a different place and it had bad diodes. Replaced the alt and never had the problem again.
I guess some places are better at testing than others.
Going to try to borrow a VR from a friend of mine and put it in and see if it makes a difference.
Le Mans Master
Joined: Oct 2000
Posts: 8,897
Likes: 1,357
From: Santa Ana CA
Here are my findings so far:
Battery with car off: 12.66 volts
Battery with car on: lower than that...anywhere from 9-12 volts, fluctuating with RPM
At regulator terminal-
Battery voltage at number 3 terminal
6 volts at number 2 terminal...should be 0
key on...voltage at number 4 terminal
At this point I am suspecting the alternator...voltage at terminal 2 is not 0 as it should be....leaking diode?
Going to see if I can borrow a regulator that is known good from a friend and see what that does, but I am leaning toward the alternator, even though it checked out OK previously.
Any thoughts?
Battery with car off: 12.66 volts
Battery with car on: lower than that...anywhere from 9-12 volts, fluctuating with RPM
At regulator terminal-
Battery voltage at number 3 terminal
6 volts at number 2 terminal...should be 0
key on...voltage at number 4 terminal
At this point I am suspecting the alternator...voltage at terminal 2 is not 0 as it should be....leaking diode?
Going to see if I can borrow a regulator that is known good from a friend and see what that does, but I am leaning toward the alternator, even though it checked out OK previously.
Any thoughts?
Thread Starter
Melting Slicks
Joined: Jul 2006
Posts: 2,346
Likes: 41
From: Toronto
Tried in a friend's voltage regulator, and it looks like the problem is solved.
The gauge stays just over 0, and is in the charging zone. Not discharging at idle anymore.
Will test the output at the battery and make sure it is correct.
Thanks for all the help
The gauge stays just over 0, and is in the charging zone. Not discharging at idle anymore.
Will test the output at the battery and make sure it is correct.
Thanks for all the help
