Alternator Help

[BigSwid79]

Great weekend I had, started with blowing out my ignition module and be stuck dead at a stop sign for an hour. Fixed the module its a 79' chevy 350 with GM HEI. I'm figuring the module blew because I've been having surges in my charging system. My battery has been charging and then discharging. My solution to this was get a 100amp 1 wire alternator. Did that and got it hooked up. I'm running the wiring from the starter up to the alternator, which then connects into the wiring to the fuse box, it looks all good. Then i got a wire coming off that same post on the alternator right to the positive battery terminal. Then I made a self exciter where the plug in would go. Seemed like the battery charged fine, but then this morning I got up and the truck was dead. Is there anything in this set up that would be draining m battery. I need help quick I'm sick of messing with this chevy, i'm starting to think its a ford in disguise.
Swid

[storm9c1]

Originally Posted by BigSwid79

Then I made a self exciter where the plug in would go. Seemed like the battery charged fine, but then this morning I got up and the truck was dead. Is there anything in this set up that would be draining m battery. I need help quick I'm sick of messing with this chevy, i'm starting to think its a ford in disguise.
Swid

Whoa, wait, how did you hook up the exciter? To what power source?

[VetteVet]

I'm curious about that as well because one-wire alternators are self exciting. If you have run a jumper from the large post on the back of the alternator to the exciter terminal then you may have damaged the diodes in the alternator and caused a current leak to the alternator housing which is grounded.

Given that you have run three wires to the positive feeds off the battery, you need to be sure that each one has a fusible link to prevent burning up the wiring harness if the battery cable shorts against the frame or exhaust pipe.Most one-wire alternators only run a single wire back to the battery terminal or to the starter cable terminal.

[BigSwid79]

yeah guys i messed up the wiring, I had a mechanic friend over and he was alittle off with the wiring. Today I rewired it the right way I believe. I took alook at my brothers 86' chevy with a fast burn 350 it has a one wire set up. I copied that and it seems like its working. i just got one wire running from the post to the battery positive. Then i got one wire jumping from i think the positive or field side? of the plug in to the post. I got ride of the factory harness to the alternator and capped it off. Hopefully this does the trick for me cause im tired of blowing modules, changing batteries and alternators!

Thanks Swid

[VetteVet]

Well If I am reading your post correctly, you are wiring the large post on the alternator to the battery terminal, but you are also wiring the plug-in on the original harness to the large post as well. Then you say that you got rid of the original harness. What did you do with the wires that went to the plug? If you jumped the plug sensor wire to the large post on the alternator then it was not necessary because the alternator is self exciting and the only thing needed is a wire to the positive battery terminal. That's why it's called a one-wire alternator.

[storm9c1]

Now I'm confused. If there is a plug on the side, typically that is the exciter/field winding. This usually goes to a switched ignition source. If you connect that to the charging post, it will always be energized and drain the battery even with the key off... So how can that work?

[VetteVet]

Don't be confused because you are correct. However there are two terminals in the plug and in the alternator. NO.1 is the exciter to the ignition source which must have a resistance in it. NO. 2 is the sensor wire and it is wired directly into the 12 volt battery circuit. If these two are reversed then the alternator diodes will fail and the battery will drain through them to the ground and kill the battery.

[VetteVet]

Here is a diagram to convert the external regulator to the newer internal regulator. It is only necessary to extend the brown exciter wire to the no.1 terminal on the alternator by jumping it to the white wire in the stock harness, and jumping the red wire to the blue wire to no.2 terminal on the alternator. It doesn't show it but the red wire junction circled in the diagram is a direct feed from the battery positive.

The one-wire does not use anything but the larger red wire on the back of the alternator.

[storm9c1]

Originally Posted by VetteVet

Here is a diagram to convert the external regulator to the newer internal regulator. It is only necessary to extend the brown exciter wire to the no.1 terminal on the alternator by jumping it to the white wire in the stock harness, and jumping the red wire to the blue wire to no.2 terminal on the alternator. It doesn't show it but the red wire junction circled in the diagram is a direct feed from the battery positive.

The one-wire does not use anything but the larger red wire on the back of the alternator.

Attachment 816019

Yes, that is what I'm familiar with and have seen that jumper to convert external regulated alternators to internally regulated. I'm still confused on what the heck the OP is was trying to explain. LOL.

[oldgold70c10]

Originally Posted by storm9c1

Yes, that is what I'm familiar with and have seen that jumper to convert external regulated alternators to internally regulated. I'm still confused on what the heck the OP is was trying to explain. LOL.

After rereading the original post, I think he thought he was wiring an alternator '1 wire'. I'm confused! A one wire alternator is literally that-there is only 1 place to attach 1 wire. There is usually a little piece of plastic on the 10SI 1-wire units to seal off where the 2-wire plug would go. If it has the side terminals, then it is not a 1-wire alternator, and can not be wired as such. The Bat and No. 2 terminals go to the battery, the No. 1 terminal goes to a switched power source through a light bulb (idiot lights), or a resistance (ammeter, voltmeter). On the 67-72's, it is wired to the accessory power thru the ignition switch, and the resistance is provided by 7-8 feet of 24-26 gauge wire.

Was that it?

[VetteVet]

Originally Posted by oldgold70c10

After rereading the original post, I think he thought he was wiring an alternator '1 wire'. I'm confused! A one wire alternator is literally that-there is only 1 place to attach 1 wire. There is usually a little piece of plastic on the 10SI 1-wire units to seal off where the 2-wire plug would go. If it has the side terminals, then it is not a 1-wire alternator, and can not be wired as such. The Bat and No. 2 terminals go to the battery, the No. 1 terminal goes to a switched power source through a light bulb (idiot lights), or a resistance (ammeter, voltmeter). On the 67-72's, it is wired to the accessory power thru the ignition switch, and the resistance is provided by 7-8 feet of 24-26 gauge wire.

Was that it?

Your post gives me the chance to post up a few diagrams to help everybody see how it works . Your understanding of how it works is correct except for, (a resistance (ammeter, voltmeter). . They have no effect on the alternator and they have no resistance other than the internal resistance that protects the instrument. Other than that you are spot on.

Look directly at the center of this diagram and locate the resistance wire that connects to the ACC on the ignition switch and the brown feed wire that connects to the idiot light in the cluster. Follow them and it's easy to see the connections you pointed out. This is for the internally regulated alternator.



This is one for the internally regulated alternator on a 74 buick which is the same as the chevy truck conversion.



This is the same only on an externally regulated system. This shows the light and the resistance wire. If the cluster has an ammeter it will not have the light. If a conversion to an internally regulated alternator is desired then it is only necessary to extend the no. 4 brown wire to the no. 1 terminal on the internally regulated alternator, and to extend the red wire at no. 3 to the no. 2 wire on the alternator. It's as simple as that. I posted the diagram in a previous post above.

[oldgold70c10]

Ah, I should have been more clear. With an ammeter or voltmeter setup, a resistance is used instead of the lamp. I wasn't trying to imply that the resistance came from the ammeter or voltmeter. Here's the diagram I based my description on, its from the 74 chevy service manual.

[VetteVet]

I know you understand the system and I thought it was something like that. Thanks for your help on these problems.VV