PLEASE HELP: Converting from External to Internal Voltage Regulated Altenator

[grif]

Hi folks,

I'm experiencing charging problems with my 1971 K20. It's never charged correctly since I've owned it - the battery drains if I drive it for more than an hour or so.

I've replaced the alternator and external voltage regulator without success. I'd like to convert to an internally regulated alternator (which may or may not solve my problem), but the wires coming from my voltage regulator are different than the pictures in toddtheodd's post in the FAQ:
http://67-72chevytrucks.com/vboard/s...d.php?t=119379

I have attached a photo of my voltage regulator wiring. The previous owner re-wired with a painless wiring harness. The blue and brown wires run to the alternator. I'm not sure where the white wire goes, but it is jumpered to another terminal on the voltage regulator. Is anyone familiar with this wiring configuration?

Any ideas why I am not getting a charge and how I wire up the internally-regulated alternator?

Thank for you help!
Grif

[seafoam68]

Me too. Anyone?

[VetteVet]

That would appear to be a solid state regulator and it's definitely wired differently than stock. You need to trace the wires and see where they go and where they come from.

Here is the wiring diagram from the stock factory issue.



The solid state regulator should be wired the same as the stock regulator.
You should have a 16 gauge brown wire coming from the firewall connector to the no. 4 terminal on the regulator which will be on one end or the other and it should be marked 1 2 3 4.
The no. three wire was a red 12 gauge wire that comes from the alternator battery wiring junction. It is easy to check because it is hot all the time.
The no.2 wire was awhite wire that goes from the regulator to the alternator R terminal, and the no. 1 wire was a blue wire that runs from the regulator to the alternator F terminal.

If the no. 2 and the no. 1 wires are switched then you would not charge and the battery would drain in a short time especially when driving with the lights on.

If you decide to convert to an internally regulated alternator, Start a thread in the electrical forum or have a mod move this one over there and I will help you do it right. VV

[VetteVet]

Holy crap I just realized you live in plainwell.

[grif]

Originally Posted by seafoam68

Me too. Anyone?

Seafoam68, is your regulator wired like mine?

[grif]

VetteVet - thanks for the wiring diagram! I'll see if I can locate the 16 gauge brown wire that should be coming from the firewall connector to the no. 4 terminal on the regulator. The white wire in my picture (the one that is also jumpered to a second terminal on the regulator) says "alternator exciter" on it. There is no red 12 gauge wire that is constantly hot anywhere near the regulator. Very strange!

How can I test the white wire labeled as "alternator exciter" to verify that this is doing the same thing as the the 16 gauge brown wire that would have been originally coming from the firewall connector?

I sure do live in Plainwell, just up the road from you. Thank you for your help.

[VetteVet]

Hi Grif. The exciter wire from the firewall block and the cab originates at the key switch on trucks with the gauge dashes and at the charging light on trucks with the idiot light dashes. Either way the wire comes through the fire wall connector as a 16 gauge brown wire and goes to the voltage regulator on one of the end terminals.

It should have zero voltage on it with the key off and 12 volts with the key on. Measure it with a voltmeter and if the white wire is the exciter wire, it should show those readings. I have not seen any of the four wires jumpered to any other terminal on the regulator unless it is some special type of regulator I'm not aware of.

Here's a diagram showing what I have said.



As you can see the wire to no. 4 on the regulator is the exciter wire and it exits the regulator at terminal 2 and goes to the R terminal on the alternator.

The wire on terminal 1 goes to the alternator to the F terminal and was a blue wire on the original harness. If the F and R wires are switched at the alternator or the regulator, The blue wire which has 12 volts on it, will drain through the alternator diodes to ground and discharge the battery.

This is the plug in your alternator .



The black wire is a ground and should also be connected to the regulator which should be grounded to the radiator core support.



Hope this helps.

[Jurassic-1]

Another way is to purchase the adapter kit which has a wire adapter that plugs in where the regulator plugs in a d an adapter at the alternator end. the nice thing is you can still install the old style in a pinch by unplugging the wire adapter. I bought my kit from Brothers years ago. it is around $20.00

[grif]

Hey Jurassic-1, I've heard of these adapter kits but my regulator doesn't have a plug. The four wires connect individually via separate quick disconnect terminals.

[grif]

VetteVet, you've been a great help. Using your pictures and diagrams, I believe the problem was that the previous owner had the F and R wires switched at the regulator. I was getting a little less than 13 volts on the battery with the truck running. After switching the F and R wires on the regulator, my new reading is up around 14 volts.

The white wire does appear to be the exciter wire; I have gauges (not idiot lights) and this wire has zero voltage on it with the key off and 12 volts with the key on. This wire is connected to terminal 3 and jumpered to terminal 4 on the regulator.

I do believe I would like to convert to an internally regulated alternator. Can a mod please move this thread in the electrical forum? Since my voltage regulator is unusually wired, I'll need a little help.

Thanks!

[WIDESIDE72]

I have run the adapter mentioned above on several trucks. It just has male tabs on it and jumpers internally where necessary. As long as the wires on your regulator are performing the same function as those on an original connector the adapter will still work. Just unplug them from your regulator and replug them on the adapater individually.

[grif]

When I re-wire for the internally regulated alternator, is the process the same for trucks with gauge dashes and idiot light dashes? I have a gauge dash and need to know if I should follow toddtheodd's directions here:

http://67-72chevytrucks.com/vboard/s...d.php?t=119379

toddtheodd's directions appear to be specifically for idiot light dashes.

[VetteVet]

The conversion is fairly simple especially if you have a stock harness.

The difference between the gauge dash and the idiot light dash is, where you run the large output wire from the alternator. If you run it anywhere but to the stock location then the battery gauge might not work.

Here is the stock wiring.





here is a simple jumpered conversion.



Notice all you do is pull the plug off the external regulator and jump between the no. 2 and your exciter wire which is white.

Then jumper between the no. 1 and the wire which is hot all the time on your regulator. In the stock harness it's a jumper between the brown and white wires and the red and blue wires.

I think I have it figured out on your solid state regulator. The white wire serves as the brown exciter wire with the jumper to the no, 4 position where the brown wire normally goes and it also takes the place of the no.3 wire which is normally hot all the time, because when you turn the key on it also becomes hot.
Then 1 and 2 go to the alternator where 2 connects to the R terminal on the alternator and 1 connects to the F on the alternator. I believe you had those two reversed at the alternator, didn't you say that.

When you do your conversion you only need to run the white wire on your setup (which should be brown) to the no. 1 on the SI alternator and then you have a choice to loop the no. 2 wire on the alternator to the large post on the back of the alternator Like Todd does or you have to run a separate wire from a junction of the battery and alternator feeds like the diagram shows.

I prefer to do that because it gives the regulator in the alternator, a better sense of what the voltage is in the circuit nearer to the draws on the battery, and will allow it to step up the output voltage to compensate for those draws.

Setting it up like Todd does will work but it only tells the regulator what the voltage is at the back of the alternator and you could actually get dim lights and low power in the cab.

In a nut shell all you have to do to get the internally regulated alternator to work, is to wire the exciter wire from inside the cab to the no1 terminal on the
SI alternator and run a 12 volt source that is hot all the time to the no. 2 terminal on the SI alternator .

This is how I do it and it is clean and neat and gets rid of the external regulator altogether. It shows the exciter wire coming from the firewall connector as a brown wire which it is in the stock harness. Check the first diagram above.
Then I just run the Red wire (hot all the time) from the junction Which is circled in red in the first diagram to the alternator voltage sensing terminal no. 2.



You can buy the SI alternator plug in any of the autoparts stores for about $5 or just get one at the local pick a part junkyard. Then you just splice the two wires in.

[Jurassic-1]

Yes the quick connect or crimp on terminals can simply be transfered on the coresponding terminals.

[grif]

Thanks, VetteVet. You've made this sound pretty simple. My only question has to do with running the separate wire from a junction of the battery and alternator feeds:

Originally Posted by VetteVet

Then I just run the Red wire (hot all the time) from the junction Which is circled in red in the first diagram to the alternator voltage sensing terminal no. 2.

What does this existing junction look like and where can it be found? I'm looking for a 12 gauge red wire coming from the firewall connector, right? Can I run this wire directly from the positive battery terminal instead?

Thanks for all your excellent hep!

[VetteVet]

Originally Posted by grif

Thanks, VetteVet. You've made this sound pretty simple. My only question has to do with running the separate wire from a junction of the battery and alternator feeds: SEE NO. 2 BELOWWhat does this existing junction look like and where can it be found? I'm looking for a 12 gauge red wire coming from the firewall connector, right? Can I run this wire directly from the positive battery terminal instead?

Thanks for all your excellent help!

This will lead to a tutorial on how the battery gauge works and how it's important to wire the battery and alternator feeds a certain way.

The battery alternator junction is buried in the wiring harness on the left side of the truck in the main harness and it looks like this.



It is simply a four wire junction soldered together. if you have the gauge dash with the battery gauge you will have a small black wire eith a white stripe soldered there also. On the 1966 and older year trucks they used the orn relay for this junction

These wires consist of
1. The large wire from the back of the alternator
2. The red sensing wire for the external voltage regulator to the no.3 terminal or it can be run to the no.2 terminal of the internally regulated SI alternator. or if you want more amps then it can be run to the S terminal of a CS alternator. This is the wire that does the remote voltage sensing for the alternator and allows it to compensate for voltage drops in the downstream loads of the circuit such as the electric cooling fan, the heater fan, and the wiper motor etc.
3. The cab feed wire which is the 12 gauge red wire that runs to the firewall connector block and feeds the circuits inside the cab.The headlight switch, The ignition switch, the fuse panel, and the horn relay.
4. The fourth wire is a 12 gauge wire that runs from the terminal on the passenger fender across the radiator and down into the harness to the junction. This wire is called the SHUNT because it connects the battery positive terminal to the alternator output feed wire in order to charge the battery. This is the wire which feeds all the circuits when the alternator is not working.
There is a common misconception that the battery is what supplies all the power for the vehicle and the alternator just recharges the battery. In fact the alternator supplies the power and the battery is used for starting and backup and it supplies power during load switching to reduce surges from the alternator.

This soldered junction can be replaced by most any type of aftermarket junction or fuse panel and I recommend it when upgrading the electrics on the truck.

This brings us back to the SHUNT wire and the battery gauge wires. There are two small 20 gauge wires that feed the battery gauge that us old timers use to call the ammeter. One of them is connected to the soldered junction and it goes into the cab to the dash cluster plug to terminal 1. The other one is connected to the junction on the passenger fender with the fusible link wire from the battery positive terminal. It runs through the firewall connector block to the cluster plug to terminal 12. It is usually a solid black wire.

Notice in the diagrams above these wires are shown connected as stated with two small fuses inline to protect the gauge in case of a short or break in the main feed wire which would alll all the alternator or battery feed voltage to go through the gauge and burn it up. One or the other of these two fuses is the main reason that the gauge doesn't work when someone buys a truck with the ammeter in it. They are only 4 amp fuses and they are located in the harness by the left headlight and by the passenger fender junction. They are easy to spot because the holders look like a small black football.

The next item is the shunt wire that is just a normal 12 awg wire running from the passenger fender junction across the radiator to the soldered junction. It's purpose is to shunt power from the alternator to the battery and back from the battery to the system. It's length and resistance is calibrated by the factory for the truck's demand and the battery gauge is matched to those factors.

Here's a good diagram I've posted many times that shows the wiring I've been discussing. The shunt wire is labeled and the fuses are circled.



Notice that the ammeter wires are connected on each end of the shunt
wire. This is so the gauge can sense which voltage is higher or lower the battery voltage or the alternator voltage. Normally the alternator voltage will be higher so the gauge will read charging or to the right of center. If the battery voltage is higher it means that the alternator is not charging and the gauge will read to the right or discharge.

If the alternator output wire is run directly to the battery post or to the passenger fender junction or even to the starter cable connection it will still work the system but that bypasses the shunt wire and the gauge won't be able to read accurately.

Here are the in cab wiring diagrams and you can follow the large red wires and see how they feed the cab circuits I mentioned above. This one shows the red feed wire from the soldered junction coming through the firewall block and feeding the Key switch and the horn relay and the fuse panel.




This one shows the red wire feeding the fuse panel.




This one shows the red wire feeding the headlight switch

[RichardJ]

I found this image on the internet years ago. As you can see, they used the shortcut version of the wiring that many use when installing an internally regulated alternator. The DN shown is wired the same way and is how yours is wired.

In the images, both the DN and SI wiring have TWO wires coming away from the respective Alt/Regs. Both have a Red Battery wire and a Brown exciter wire that goes to the ignition switch. Your white wire is an obvious rewiring job and you will have to trace it yourself. The junction of the several Red wires that VetteVet is showing you was buried inside the original harness.

If you are still using the original Ammeter, that junction is fairly important. You can see the black and grey wires with fuses in the VetteVet drawings. Those wires go into the Ammeter. The large Red wire that connects the Black to the Grey wires has two purposes. The second purpose is to act as the shunt for the Ammeter. If that Red wire is too fat or too short, the Ammeter will read too low. If the Red wire is too small or too long, the Ammeter will read too high. The resistance of that Red Battery wire was calibrated so that the correct amount of current would flow through the Ammeter and give the correct reading.

The external regulator is labeled "F",2,3,4. Regulator wires F & 2 go to the Alt and nowhere else. On a conversion to Internally Regulated Alt, the F & 2 wires disappear inside the Alt, never to be seen again.

The #4 Exciter wire on the old Reg plug, is moved to the #1 post on the Int Reg and serves the same function.
The #3 Sensing wire on the old Reg plug, is moved to the #2 post on the Int Reg and serves the same function.

[RichardJ]

If you decide to keep that external regulator, make sure the base of the regulator is grounded. Originally there was a short pigtail wire that was bolted to the radiator core support. The original rubber feet were for vibration protection.

[grif]

Thanks for the replies, fellas. I finally had a chance to get out to the shop to have a look under the hood. I was able to locate the battery alternator junction which is a little different on my Painless wiring harness, but I did find it.

What's the best way to splice in the wire that runs to the no. 2 terminal on the SI alternator? I have four wires there already (see red wires in the pic) and I'm adding in a fifth. The Painless harness had the four wires connected within some sort of crimped copper band with heat shrink around it. Five wires is quite a junction, especially when there are some 12 gauges wires in there. Any suggestions on how to make this junction?

Thanks!

[70blackfish]

ttt

[VBerg84]

Vette Vet, your information and explanations here helped me to trouble shoot my own, external regulated alternator not charging issue. I formerly had replaced the alternator, bench tested the regulator (it was good), and finally decided that it had to be in the harness and rather than try to sort thru the cobbled mess I ordered and replaced the complete front end wire harness all the way up to the firewall. Having just recently completed some engine and interior work (fuel tank, sending unit, and refinishing the instrument cluster) I finally have it running again, only to find I STILL had a no-charge system. Using your detailed explanations I chased my way thru the system and in about a half and hour I found my issue. The cab side of the firewall electrical connector was missing the female lock terminal for the brown wire! I have spliced the new terminal in and will finish putting the fuse panel back together next weekend. I found your information very complete and useful. Thank you!

[VetteVet]

Originally Posted by VBerg84

Vette Vet, your information and explanations here helped me to trouble shoot my own, external regulated alternator not charging issue. I formerly had replaced the alternator, bench tested the regulator (it was good), and finally decided that it had to be in the harness and rather than try to sort thru the cobbled mess I ordered and replaced the complete front end wire harness all the way up to the firewall. Having just recently completed some engine and interior work (fuel tank, sending unit, and refinishing the instrument cluster) I finally have it running again, only to find I STILL had a no-charge system. Using your detailed explanations I chased my way thru the system and in about a half and hour I found my issue. The cab side of the firewall electrical connector was missing the female lock terminal for the brown wire! I have spliced the new terminal in and will finish putting the fuse panel back together next weekend. I found your information very complete and useful. Thank you!

Good for you and you're very welcome. Thanks also to everyone who chimed in with great input and advice. VV