Alternator wiring question
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Instructor
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Alternator wiring question
1970...Have a stock alternator now. Found one online that is 120 amp. They say you can hook it up in stock fashion or convert to one wire. The only advantage I am aware of with the one wire connection is a cleaner look. The company sais it is one wire straight to the battery. Does that mean you lose the use of your amp gauge. Asking people to weigh in on the subject. Wiring diagram would be great. Before and after pictures would be even better.Also, if I stay with conventional configuration what wires do I have to upgrade? Thanks in advance..Matt
Le Mans Master
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From: Gladstone MO
C3 of Year Finalist (appearance mods) 2019
The one wire even at 120 amps, does not start charging until it sees enough RPM to excite the stator. THe GM 3 wire does the same theing, only it uses the small brown wire to excite and it starts the alternator working at idle. The PO had installed a one wire on Ol' Red, I swapped it back to a 3 wire.
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TimAt says it best, if you have an external voltage regulator, you will need an adapter plug to make it work, if you have an internal regulator, just plug it in and run a larger charge wire, I didnt remove the original wire but just added an 8 gauge parallel to it. . it will work better as a three wire. mine puts out 13.78 at idle. If its the same one I have that lifetime warranty is a good thing. the chrome doesnt look bad either. cause you cant get it in satin
this one?
http://www.ebay.com/itm/GM-CHROME-12...item564c109f17
this one?
http://www.ebay.com/itm/GM-CHROME-12...item564c109f17
Last edited by oldalaskaman; Sep 21, 2012 at 10:04 AM.
Le Mans Master
Joined: Apr 2011
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From: Hermosa
Stay with a three wire alternator. The one wire alternator was developed for systems that do not have a voltage regulator as an economical solution. Your car's voltage regulator will work better.
I bought the exact one oldalaskaman reccomended in the three wire version and it works well.
I bought the exact one oldalaskaman reccomended in the three wire version and it works well.
Thread Starter
Instructor
Joined: Feb 2008
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TimAt says it best, if you have an external voltage regulator, you will need an adapter plug to make it work, if you have an internal regulator, just plug it in and run a larger charge wire, I didnt remove the original wire but just added an 8 gauge parallel to it. . it will work better as a three wire. mine puts out 13.78 at idle. If its the same one I have that lifetime warranty is a good thing. the chrome doesnt look bad either. cause you cant get it in satin
this one?
http://www.ebay.com/itm/GM-CHROME-12...item564c109f17
this one?
http://www.ebay.com/itm/GM-CHROME-12...item564c109f17
Where do the wires from the plug in go (when they exit the alternator)and what do they do? How do I know if I have an internal or external regulator? Also I don't have the exciter wire mentioned and don't know if that is significant. Thanks
Le Mans Master
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Last edited by oldalaskaman; Sep 21, 2012 at 11:54 AM.
Le Mans Master
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Posts: 7,123
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From: Gladstone MO
C3 of Year Finalist (appearance mods) 2019
Easy to tell-- if the connector on your alternator has two terminals like this " l l " it's an external regulator. IF they are in line " -- " it's internal. Sorry-- not to scale. The terminals are about 1/4" wide.
The two wires are in the harness- the large one (red) basically is hot all the time, and the smaller one (brown) (factory color) is hot (12v+) when the key is "ON" The other two, one large red to the output stud on the alternator, and a black wire to the alternator case ground.
GM swapped over to the internal regulator in the 68 model year IIRC.
The two wires are in the harness- the large one (red) basically is hot all the time, and the smaller one (brown) (factory color) is hot (12v+) when the key is "ON" The other two, one large red to the output stud on the alternator, and a black wire to the alternator case ground.
GM swapped over to the internal regulator in the 68 model year IIRC.
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Melting Slicks
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From: Warrington PA
Finalist 2020 C4 of the Year - Unmodified
The one wire even at 120 amps, does not start charging until it sees enough RPM to excite the stator. THe GM 3 wire does the same theing, only it uses the small brown wire to excite and it starts the alternator working at idle. The PO had installed a one wire on Ol' Red, I swapped it back to a 3 wire.
"The one wire even at 120 amps, does not start charging until it sees enough RPM to excite the stator. THe GM 3 wire does the same theing, only it uses the small brown wire to excite and it starts the alternator working at idle."
On the 82 I have a 3 wire and leaving early in the morning, I ease out of the neighborhood as not to wake up anyone, as soon as I get on the road and bring the r's up the headlights get brighter. So is that when the alternator starts charging from the stator getting excited? Is this normal for a 3 wire setup? thanks...................Tom
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On the 82 I have a 3 wire and leaving early in the morning, I ease out of the neighborhood as not to wake up anyone, as soon as I get on the road and bring the r's up the headlights get brighter. So is that when the alternator starts charging from the stator getting excited? Is this normal for a 3 wire setup? thanks...................Tom[/QUOTE]
Do the lights dim when the r's drop back to idle? Aftermarket large diameter pulley will do this.
Do the lights dim when the r's drop back to idle? Aftermarket large diameter pulley will do this.
Melting Slicks
Joined: Mar 2006
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From: Warrington PA
Finalist 2020 C4 of the Year - Unmodified
Do the lights dim when the r's drop back to idle? Aftermarket large diameter pulley will do this.[/QUOTE]
No they don't, once they get brighter, they stay that way. since my dash is still out of the car, and no gauges, I use my interior dome light as a "gauge" also. when that gets real bright, it stays that way, just like the headlights. have stock pullies.....
someone had mentioned to me that the alternator may have a "soft start", now that I think about it, that may be referring to the stator being excited by a certain rpm range.
No they don't, once they get brighter, they stay that way. since my dash is still out of the car, and no gauges, I use my interior dome light as a "gauge" also. when that gets real bright, it stays that way, just like the headlights. have stock pullies.....
someone had mentioned to me that the alternator may have a "soft start", now that I think about it, that may be referring to the stator being excited by a certain rpm range.
Last edited by 74 LS4-454; Sep 21, 2012 at 09:29 PM.
Melting Slicks
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From: Warrington PA
Finalist 2020 C4 of the Year - Unmodified
Team Owner
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From: Orange Park Florida
someone had mentioned to me that the alternator may have a "soft start", now that I think about it, that may be referring to the stator being excited by a certain rpm range.[/QUOTE]
I forget wether your later sharks have a 'idiot' light or not, I believe they do have a volt meter though, IF you have a idiot light, that will be the cause, as it's not in the circuit....
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O.K. You guys have me sold on staying with three wire. Next question.......A friend gave me an aluminum alternator in great condition but with stock amps. I need more amps for my accessories. Can I or an alternator shop increase the amps. If so, what is involved?