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Username Post: Wiring when converting to a one-wire alternator        (Topic#341079)
5635Chevy 
Silver Supporting Member
Posts: 13
5635Chevy
Loc: Arizona
Reg: 10-29-15
12-06-16 02:20 PM - Post#2664871    

I currently have a standard three wire alternator, and an Autowire stock wiring harness with a generator to alternator plug-in conversion. I want to install a larger amp alternator with a one-wire set up. I understand that I can run the charge wire from the alternator to either the battery terminal on the starter or direct to the positive side of the battery. Questions are:
1. What do I do with the horn relay and the wiring for the horn relay and the horns?
2. What wiring changes if any do I do to get my volt meter in my custom gauge set up to work?





 

Jim Streib 
Senior Member
Posts: 398
Jim Streib
Loc: Saint Louis
Reg: 03-20-03
12-07-16 09:52 AM - Post#2664991    
    In response to 5635Chevy

  • 5635Chevy Said:
I currently have a standard three wire alternator, and an Autowire stock wiring harness with a generator to alternator plug-in conversion. I want to install a larger amp alternator with a one-wire set up. I understand that I can run the charge wire from the alternator to either the battery terminal on the starter or direct to the positive side of the battery. Questions are:
1. What do I do with the horn relay and the wiring for the horn relay and the horns?
2. What wiring changes if any do I do to get my volt meter in my custom gauge set up to work?





What is your reason for wanting to go with a larger alternator and then with a 1-wire design ?.

Are you going to later, or now, have more things on the car that require more amperage than what the alternator on there now can support ?.

If you have, or will be adding more things to the electrical system, where will you be getting power for those things ?.

The reason I'm asking is so you do not overload what is already in place by doing things incorrectly. The harness in the car now can only handle so much so you do not want to just randomly add things here or there.

When you talk about your horn relay, is the horn relay also doing other things like acting as a junction or distribution point ?. If you can, post the diagram or the link to the harness you have in your car currently. I can then, modify it to show how things need to be done.

Jim

1968 Chevy II Nova (Garage Find 2013)

https://www.flickr.com/photos/121766713@N04/ albums...

https://www.youtube.com/user/StlNovas/videos

1973 Nova Custom
1974 Nova Spirit Of America


 
Bruces 57 
Frequent Contributor
Posts: 2294

Reg: 01-03-07
12-07-16 09:55 AM - Post#2664993    
    In response to Jim Streib

Hello;
One wire alternators were primarly designed for tractors! Go with a 3 wire! but check out the amp output of the new one (alternator)compared with what you have.

Bruce



 
Rick_L 
Honored Member
Posts: 26966
Rick_L
Loc: Katy, Tx, USA
Reg: 07-06-00
12-07-16 10:13 AM - Post#2664996    
    In response to Bruces 57

Lots of late model cars use a one wire setup. Nothing wrong with it, done right.



 
raycow 
Honored Member
Posts: 24972
raycow
Loc: San Francisco, CA
Reg: 11-26-02
12-07-16 02:21 PM - Post#2665026    
    In response to 5635Chevy

1. Not sure I understand why you are asking this question. Are you saying that your present harness DOES NOT have the necessary connections to support the relay and horns? If it does have those connections, and the relay and horns were working before, just leave that wiring alone.

2. Same answer as #1. If your voltmeter worked before, just leave its wiring alone.

If you are still wanting a recommendation for the charging wire, I would connect it to the battery terminal on the starter solenoid. It will work the same connected to either the solenoid or the battery, but IMO it looks better on the solenoid (this is because the battery is readily visible, while the solenoid is not).

Ray

There's a line between good and evil no wider than a razor's edge - D.S. James Hathaway quoting from The Night Keeper


 
5635Chevy 
Silver Supporting Member
Posts: 13
5635Chevy
Loc: Arizona
Reg: 10-29-15
12-07-16 02:49 PM - Post#2665033    
    In response to Jim Streib

I need to support the normal stuff as well as an AC, electric cooling fans (2) on the radiator, possibly halogen headlights, a radio producing 200-300 or more watts, HEI ignition, electric fuel pump, etc.

I am looking at the one-wire internal alternator for the extra amperage, and have less wiring/stuff under the hood.

The power for all the normal stuff and the additional stuff will come from an American Autowire ATO fuse block (37139) that will replace the stock fuse block.

The horn relay is just that - no junction/distribution point.

The "under the hood wiring harness" is an American Autowire CE640761 that includes the necessary jumper wire under the dash for an internal regulator. I will try to get you a URL to them.



 
5635Chevy 
Silver Supporting Member
Posts: 13
5635Chevy
Loc: Arizona
Reg: 10-29-15
12-07-16 03:40 PM - Post#2665048    
    In response to 5635Chevy

Jim,

I cannot get the American Autowire website to give me the instruction sheets online. I have scanned the hardcopies I have, but do not know how to get them uploaded to the forum. Got any ideas?

Larry



 
acardon 
Ultra Senior Member
Posts: 10643
acardon
Loc: DFW TEXAS
Reg: 03-25-05
12-07-16 04:45 PM - Post#2665063    
    In response to 5635Chevy

For a 140 amp one wire alternator run a 8 gauge wire to the starter battery post and a 14 gauge wire to the battery terminal of the horn relay.
Remove or tape back the other wires on the alterntor.
Connect the voltmeter to any switched terminal on the fuse box.

Don
66 Corvair (driving)
57 2dr HT (driving)
56 2dr HT (waiting to be restored)


 
Jim Streib 
Senior Member
Posts: 398
Jim Streib
Loc: Saint Louis
Reg: 03-20-03
12-07-16 07:55 PM - Post#2665092    
    In response to 5635Chevy

Larry,

From what I can see on the pictures of the American Autowire CE640761, it looks like I would cut the red wire by the boot that now goes to your internally regulated alternators output post and then cap it off and tape it into the harness with the other wires.

IF for some reason you try a 1-wire and it does not work properly and it can be either switched out for a 3-wire or the 1-wire can be reconfigured, I would leave the two wire plug as it is for right now until some tests are done. If later, you find the one wire works the best, then you could cut those two wires, cap them off and tape them into the loom burying them so they are not seen.

This so far takes care of some of the wiring.

If the battery terminals on your car are of the spring type (no nut and bolt for the clamp), then the new alternator will need to be wired to the starter solenoid terminal that the main battery cable attaches to.

IF you have bolt on type of battery cable ends at the battery then you can wire the alternator there instead.

If you have solid good connection, either will work just fine. It's a matter of what's there and cosmetics.

To continue on, with the new alternator in place, you need to run the proper sized wire however you want from it's output post to either the battery or the starter solenoid and wherever this end gets connected (at the battery or the solenoid), I would put inline the proper sized fusible link.

Now with this all done, the new alternator will charge the battery and keep up with what is on the car.

Since you want to add additional things to the car, these things need to be added off of the battery as the original harness is not made to support a ton of stuff and if the AC draws let's say 25A-30A and the fans draw a total of let's say 40A, then this additional 65A or more cannot be pulled off of any of the existing wiring inside the car.

So, with that said, just because you might be getting power from the battery does not mean these added things will be on all of the time, but with the proper parts you can have things setup to where when only the key is in the run position can they draw power. This is done through a small amperage draw off of the car that will activate a relay and the cars original harness inside the car is more than enough to activate relays.

Since most of the time, you might be grounding added electric fans to the body of the car and other new things also grounded to the body of the car, you may want to also do a ground upgrade. By having a large enough ground from the body of the car to the engine block or to the battery negative, the factory grounds will not possibly be over stressed. Here again, the factory design was only large enough for what they would have put on the car and they had no way of forseeing what would be done after that.

I'm normally attuned to the late 60's and newer GM cars and wiring and what little I saw of clear diagrams on a 56 wiring diagram, you may want to investigate adding a fusible link on the original wire that feeds into the car. There may already be in place some type of protection but if one is not there, it's something worth while adding in the proper location.

Jim


1968 Chevy II Nova (Garage Find 2013)

https://www.flickr.com/photos/121766713@N04/ albums...

https://www.youtube.com/user/StlNovas/videos

1973 Nova Custom
1974 Nova Spirit Of America


 
Big T 
"11th Year" Silver Supporting Membe
Posts: 2649
Big T
Loc: Simi Valley CA
Reg: 04-14-06
12-07-16 08:37 PM - Post#2665102    
    In response to 5635Chevy

Can't help you with your relay question but maybe this might be of interest to you.

I am using a rebuilt GM 12SI originally used in a early Camaro. I bought it from NAPA for about $100.

It's output is around 98 amps. I bought a 3 wire becuse it has remote sensing.

In short it senses system demand from a remote junction other than sensing itself at its output terminal. Remote sensing example would be ajunction/distribution terminal,buss bar, power distribution center.......where all the power users tie into. What the alternator senses at that junction it will try to adjust its output to meet that demand.


FWIW. This is a web site for the rock climber truck crowd. It has a killer overload tech article about alternators, 1 and 3 wire, remote sensing, circuits and much more. There is no direct link to this page that I can find

pirate4x4.com
Click tech garage
Scroll to 2011 articles
Parts 1 and 2 should be at the top
Click part 2
Table of contents
Click Delco- Remy alternators

Tom
PS my bat is in the trunk so I used 8AWG to a firewall junction and on to the alt. My power gobblers come into the junction block on fused 10awg. Use quality automotive wire only.

Tom

55 4 door BelAir


Edited by Big T on 12-07-16 11:13 PM. Reason for edit: No reason given.

 
5635Chevy 
Silver Supporting Member
Posts: 13
5635Chevy
Loc: Arizona
Reg: 10-29-15
12-08-16 07:07 AM - Post#2665141    
    In response to Big T

Tom, Thanks.



 
5635Chevy 
Silver Supporting Member
Posts: 13
5635Chevy
Loc: Arizona
Reg: 10-29-15
12-08-16 07:08 AM - Post#2665143    
    In response to Jim Streib

Jim, Thanks.



 
5635Chevy 
Silver Supporting Member
Posts: 13
5635Chevy
Loc: Arizona
Reg: 10-29-15
12-08-16 07:12 AM - Post#2665144    
    In response to acardon

Don,

Thanks.

So the dark brown wire off the alternator voltage regulator to the front light bulkhead can go away?

Larry



 
5635Chevy 
Silver Supporting Member
Posts: 13
5635Chevy
Loc: Arizona
Reg: 10-29-15
12-08-16 07:14 AM - Post#2665145    
    In response to raycow

Ray,

Thanks.



 
5635Chevy 
Silver Supporting Member
Posts: 13
5635Chevy
Loc: Arizona
Reg: 10-29-15
12-08-16 07:14 AM - Post#2665146    
    In response to Bruces 57

Bruce,

Thanks



 
Andy4639 
Silver Supporting Member
Posts: 330
Andy4639
Age: 56
Loc: Liberty, SC
Reg: 08-06-16
12-19-16 10:44 AM - Post#2666790    
    In response to 5635Chevy

The GM 3 wire setup is much better for the vehicle hands down. Mad electric is a great source and a good read for anyone wanting to upgrade. I have done several vehicles and never have had any problems out of them. One wire alternator is fine but the 3 wire is hands down better over all. I don't know of any GM late models that are one wire alternators.



http://www.madelectrical.com/electrical-tech.shtml

Nothing finer than a garage full of classic trucks and cars! And waking up everyday to see them!
1956 Bel Air
1964 SS Impala
1967 Ramp truck
1971 C 10 my baby



 
shoeboxpaul 
Forum Newbie
Posts: 9
shoeboxpaul
Age: 68
Loc: New Freedom, PA
Reg: 08-15-16
12-31-16 04:43 PM - Post#2668750    
    In response to Andy4639

Indeed, the 3 wire is best. What is the thinking that 2 small wires are unsightly? My best friend used to think that so I am no accusing others. Mad electric is the best site for understanding alternators.




 
Rick_L 
Honored Member
Posts: 26966
Rick_L
Loc: Katy, Tx, USA
Reg: 07-06-00
12-31-16 05:56 PM - Post#2668760    
    In response to shoeboxpaul

I don't think it's because people think they are unsightly. They just don't know where to connect those two wires on the other end, or bother to find out.

I used to think the 3 wire was best until I found that GM wires many late models "one wire".



 

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