Alternator Wiring (Internal)

[DBear]

Hey guys, trying to figure some stuff out with my Burb and its alternator wiring. I swapped a 6.2 diesel into it, a 71 K10 burb. It has a internally regulated alternator on it, and I had a guy wire the motor up about 4 years ago, but recently have been re-wiring it to clean it up. I do see that he took the blue and brown wire, from the connector at the voltage regulator, and spliced them together. I have a couple of questions?

At the old voltage regulator, the are a few more wires left, a yellow, a red, and a black wires....what do I do with these?

At the split of the harness, that actually went to the alternator itself, there is a red wire, a blue wire, a black wire, and I think a yellow as well. I believe the blue wire is supposed to go to the #1 position on the alternator???? Then I thought you had to make a jumper from position #2 to the threaded post on the back of the alternator??? Then you have to run a wire from the threaded post to the positive side of the battery??? What do you do with the red that is in the harness for the alternator itself?? and the yellow, and the black?? Thanks for any help you can provide. Here are some pics..

[DBear]

well....having trouble uploading pics

[Twisted78SS]

Maybe this thread will help, http://67-72chevytrucks.com/vboard/s...d.php?t=119379

[DBear]

Originally Posted by Twisted78SS

Maybe this thread will help, http://67-72chevytrucks.com/vboard/s...d.php?t=119379

I read that one, which is a good one, but I didn't see anything about running a seperate wire from the threaded post straight to the battery. The guy who wired the 6.2 diesel, seemed to have ran a heavier gauge from that point to the battery. Also, what do I do with the black wire, which has an eyelet on the end, that is in that bundle of wiring for the alternator??? Thanks

[Twisted78SS]

I see what you mean, I had this post bookmarked for when I made an alternator based battery charger, it has some wiring diagrams that might help
http://theepicenter.com/blog/generator-projects/

[VetteVet]

Originally Posted by DBear

I read that one, which is a good one, but I didn't see anything about running a seperate wire from the threaded post straight to the battery. The guy who wired the 6.2 diesel, seemed to have ran a heavier gauge from that point to the battery. Also, what do I do with the black wire, which has an eyelet on the end, that is in that bundle of wiring for the alternator??? Thanks

Your better off not running the output wire off the alternator directly to the battery. You should use a larger gauge and run that wire to the main junction of the harness. The sensing wire that ToddTheOdd loops to the large output wire should run to the main harness as well. It gives the alternator voltage sensing circuit a better reading of the voltage drop away from the alternator and allows the alternator to charge longer in it's cycle to keep the voltage at the main junction high enough to operate the loads at 12 volts.

Wiring the internally regulated alternator is really easy whether it's the SI style or the newer CS type.
The key to the wiring is to locate the brown exciter wire from the firewall junction which should be the no.4 wire on the external regulator plug. You merely need to extend this wire to the no.1 terminal on the SI alternator. then the red wire on the EVR plug is extended to the no. 2 plug on the SI alternator. The output wire which is upgraded to a nol 10 or a no.8 gauge runs to the main junction where all the red wires meet in the harness.

Here is the diagram.




If you have the CS alternator, then You will have a different plugin in the alternator with the terminals F S L P or P L I S which the brown wire goes to the L terminal and the red wire goes to the S terminal.
In addition you have to add an extra resistor inline with the brown wire to protect the diodes inside the alternator. 85 ohm 5 watts is what Painless Wiring recommends, but a lot of guys have used as high as a 300 ohm 1 watt with success.

Here is that diagram.

[DBear]

Originally Posted by VetteVet

Your better off not running the output wire off the alternator directly to the battery. You should use a larger gauge and run that wire to the main junction of the harness. The sensing wire that ToddTheOdd loops to the large output wire should run to the main harness as well. It gives the alternator voltage sensing circuit a better reading of the voltage drop away from the alternator and allows the alternator to charge longer in it's cycle to keep the voltage at the main junction high enough to operate the loads at 12 volts.

Wiring the internally regulated alternator is really easy whether it's the SI style or the newer CS type.
The key to the wiring is to locate the brown exciter wire from the firewall junction which should be the no.4 wire on the external regulator plug. You merely need to extend this wire to the no.1 terminal on the SI alternator. then the red wire on the EVR plug is extended to the no. 2 plug on the SI alternator. The output wire which is upgraded to a nol 10 or a no.8 gauge runs to the main junction where all the red wires meet in the harness.

Here is the diagram.

Attachment 1569993


If you have the CS alternator, then You will have a different plugin in the alternator with the terminals F S L P or P L I S which the brown wire goes to the L terminal and the red wire goes to the S terminal.
In addition you have to add an extra resistor inline with the brown wire to protect the diodes inside the alternator. 85 ohm 5 watts is what Painless Wiring recommends, but a lot of guys have used as high as a 300 ohm 1 watt with success.

Here is that diagram.

Attachment 1569994

thanks for your information.....that raises another question? When the guy wired up the diesel, he did not include the standard junction box on the fender near the battery. I do have a couple if you feel I need it. AND...I did fail to mention that this is a 2 battery set up for the diesel...does that change anything? Again, thanks for the help guys...

[VetteVet]

You can use it if you want to wire it like the stock trucks. It was used to provide a place for the fusible link wire on the the battery charge wire to fuse the battery power to the truck and also to mount the battery side of the ammeter gauge in the gauge dashes.

If you notice in my diagrams above, the battery side and the alternator side ammeter sensing wires are shown in the diagram as is the fusible link. If you have the ammeter gauge in your dash and you want it to work you will need some place near the battery to mount the wire. That is another reason you can't run the alternator output wire directly to the battery.

The battery gauge( ammeter) has to have a connecting wire between the battery and the alternator, with a sensing wire on each end in order to sense the voltage of each one. The red wire on the left side of my diagrams is this wire called a SHUNT. It also serves as the charging wire for the battery.

After GM converted to the voltmeter gauge, they no longer needed this shunt wire and they routed the alternator output wire to the starter solenoid where they connected it with the main positive battery cable. They made the change in 1975 I believe. They also mounted the feed wires to the truck here, and used fusible links in the wires to fuse them.

There are a couple of ways to wire in two batteries in the trucks. they can be wired together full time or they can be wired separately by using a battery isolator. Either way it does not affect the alternator wiring. IF they are wired in correctly, each one will charge from the alternator. I have a couple of diagrams to illustrate this. i'll see if I can find them and post them up.

[VetteVet]

Here is a few wiring diagrams for the batteries with the isolator.

To wire the two batteries together you just run the positive cable of the auxiliary battery to the positive cable of the main battery and ground the negative post. Wired like this the two batteries would be like one big battery and when one goes dead they will both be dead.

Here are the diagrams.

[DBear]

Originally Posted by VetteVet

Here is a few wiring diagrams for the batteries with the isolator.

To wire the two batteries together you just run the positive cable of the auxiliary battery to the positive cable of the main battery and ground the negative post. Wired like this the two batteries would be like one big battery and when one goes dead they will both be dead.

Here are the diagrams.

Attachment 1570151


Attachment 1570152


Attachment 1570153


Attachment 1570154

Thanks for the reply...I am pretty sure the batteries were not wired with any isolator, and please bear with me because wiring is not my strong suit. I am just trying to do this the best and most dependable way. I will go with any suggestion you think is best. I guess if you think I should run a isolator, then I would probably ask where to buy and what kind is best. Thanks again

[DBear]

oh, and also, the 2 batteries are just for starting the diesel, and some of those diagrams talk about deep cycle batteries for aux equipment or something....probably just confusing to me and not the experts...lol

[Wrenchbender Ret]

You won't need the isolator if you are using both bats. for starting. The isolator is for using one battery for auxiliary equipment like on a camper. The alt. charges both bats. but you can run down the aux. bat. & still start the truck.

[DBear]

So with this said, I guess I would run the batteries in series...neg to neg and pos to pos? And, should I go ahead a use a junction box from the alternator and then to the battery?

[starterman99]

The 6.2L diesel had the battery positive to battery positive to starter solenoid and the negative from each battery to the block for ground.

[DBear]

Originally Posted by starterman99

The 6.2L diesel had the battery positive to battery positive to starter solenoid and the negative from each battery to the block for ground.

bear with me..lol. so I can run a cable from battery pos across to battery pos, and then just run to short neg cables to the block? the guy who wired it originally, ran a long cable from neg to neg on the batteries, which I wasnt sure if I needed to this time. thanks again for the info.

[starterman99]

Yes you can run two grounds to block or battery neg to battery neg then to block. If you run only one ground to block it should be a very heavy cable. Diesels take a lot of current to start that is the reason for two batteries. The positive should be battery pos to battery pos then to starter solenoid and again heavy cable.

[VetteVet]

Here is a wiring diagram that I think would allow the use of a two battery setup with the second battery used just for starting. It is wired in parallel with the main battery and would charge anytime off the alternator. It would not go dead if there was a drain on the main battery because it is wired through the Ford solenoid.

The purple solenoid wire would activate the ford solenoid and the starter solenoid. The glitch might be that the purple wire might not be able to activate both solenoids. I'm still working on that.

The ammeter wires are wired so that the gauge should work just like it does with a single battery and if it doesn't the just change to a voltmeter.



The diagram posted smaller than I wanted so it may be hard to read.

[VetteVet]

Originally Posted by VetteVet

Here is a wiring diagram that I think would allow the use of a two battery setup with the second battery used just for starting. It is wired in parallel with the main battery and would charge anytime off the alternator. It would not go dead if there was a drain on the main battery because it is wired through the Ford solenoid.

The purple solenoid wire would activate the ford solenoid and the starter solenoid. The glitch might be that the purple wire might not be able to activate both solenoids. I'm still working on that.

The ammeter wires are wired so that the gauge should work just like it does with a single battery and if it doesn't the just change to a voltmeter.

Attachment 1570738

The diagram posted smaller than I wanted so it may be hard to read.

Also I forgot to add the charging wire for the auxiliary battery with a diode to keep it isolated from the main circuit. I think you could use a switched relay instead of the diode to charge the aux battery manually.



This is just a rough draft of an idea I had but I think it would work. I welcome all comments, good or bad. LOL

I don't know if the auxiliary battery would over charge this way but if it did the manual switched relay would allow you to charge it as needed. I would wire in a voltmeter to keep track of the charge voltage just in case.