[Chuck]

I can not get the system to charge. I have a 67 SS with a guage dash (Ampmeter & oil pressure). I can not install an internally regulated alternator because I need the clearance provided by the step in the case of the externally regulated alternator to clear the tall valve covers. The internally regulated alternators do not have this step in the case so I have to go external.

I just replaced the alternator this morning. I have a solid state regulator in the car that is a few months old. I tested continuity of the 2 wires from the alternator to the regulator and the continuity of the red, charge, lead from the alternator to the battery. All is good, maybe a quarter of an Ohm max.

I measured 12.6 Volts at the battery with the engine off key off. When I fired it up I read 12.5 Volts. Where do I go from here?

Thanks
Chuck

 

[elcamino66]

Do you have the solid state voltage regulator grounded by the lug on the bottom of the regulator?

 

[Chuck]

No Thomas, the regulator is not grounded at all (which seems odd considering my knowledge of electronics). It is floating on the rubber shock mounts? Did I screw up???? The lug on the underside is tied to the lug with the brown wire attached.

So do I go from the "push on" lug on the regulator bottom to ground? In a previous life I gounded the regulator body and blew the regulator. There MUST be a ground, it would seem, so I assume from what you are saying the the lug under the regulator is the ground?????

Thanks
Chuck

 

[Chuck]

Hey Thomas

You asked if the pin on the underside of the regulator was grounded but never said if it should be grounded or not. I grounded it but am waiting for a reply before starting it so I don't blow something up????

Thanks
Chuck

 

[elcamino66]

Yes it must be grounded.

 

[Chuck]

Thanks for the help Thomas. It is now grounded but it is still 12.5 Volts KOEO and 12.2 Volts with the engine running. I have been told that it would be too high if the regulator was bad. ????

Thanks Thomas.
I give up. I guess I have to take it to the shop.

Chuck

 

[Elcoman]

The battery could also be bad. it may take a charge from a battery charger, but an alternator may not have enough power to charge a battery. The plates in the battery get deposits on the outside of them, that the alterntor can not get through. i don't know the technical terms though.
I did a CS swap and the battery would not charge. I had plenty of power everywhere. The gen light was on. The battery tested good at Autozone three times, just said needed recharge. I read somewhere about the plates getting buildup that an alternator could not charge, went to Autozone exchanged battery. No problems after that.

 

[Chuck]

I wish it were that simple. The battery is new, within 2 months and the old one did not charge either. The alternator is new and the solid state regulator is six months old but I doubt it ever charged because the ground was missing until last night.

Could it be a faulty regulator and get no voltage out of the alternator?

Thanks
Chuck

 

[1Fast7D]

Hey Thomas
You asked if the pin on the underside of the regulator was grounded but never said if it should be grounded or not. I grounded it but am waiting for a reply before starting it so I don't blow something up????
Thanks
Chuck

Yes it must be grounded.

No, it is not directly grounded. That terminal, which is tied to terminal 4 (brown wire) originally went to a capacitor which I believe was to prevent radio noise. Grounding the brown wire makes the GEN light turn on and it will never charge. If you don't have one, don't connect that terminal to anything.

No Thomas, the regulator is not grounded at all (which seems odd considering my knowledge of electronics).

The regulator body must be grounded.

It is floating on the rubber shock mounts?

Since it is on rubber shock mounts, make a small jumper with a ring terminal on each end, one side to a regulator mounting screw the other to a good ground, and make sure the small ground from the battery to the fender is present.

 

[1Fast7D]

The battery could also be bad. it may take a charge from a battery charger, but an alternator may not have enough power to charge a battery. The plates in the battery get deposits on the outside of them, that the alterntor can not get through. i don't know the technical terms though.
I did a CS swap and the battery would not charge. I had plenty of power everywhere. The gen light was on. The battery tested good at Autozone three times, just said needed recharge. I read somewhere about the plates getting buildup that an alternator could not charge, went to Autozone exchanged battery. No problems after that.

With some CS alternators, because of their high output, if battery voltage is to low they will not charge. This is to protect the battery and the alternator. They also have overheating protection and will not charge if the alternator overheats. If the battery is low, it should be charged with a battery charger first before installing in a car, especially with CS alternators.

 

[cherokee bill]

Do you have the solid state voltage regulator grounded by the lug on the bottom of the regulator?

check your ballast resister,it is rare ,but they do fail.

 

[1Fast7D]

I wish it were that simple. The battery is new, within 2 months and the old one did not charge either. The alternator is new and the solid state regulator is six months old but I doubt it ever charged because the ground was missing until last night.

Could it be a faulty regulator and get no voltage out of the alternator?

Thanks
Chuck

There was also a bad batch of regulators (solid state) where the GEN light would still be on but they were charging. It was posted over at camaros.net. Just to be sure, check voltage at battery with car running, which should be 14-14.5 volts (which looks like you were already doing)

This was written by another member, a very good write up on how it works and how to troubleshoot a externally regulated charging system.

I dug this out from before, hopefully it help. If not, just post or send me your questions.

I'll try to provide a simplified explanation of how the externally regulated alternator and regulator work here. This explanation starts from a parked car with engine off state.

The regulator brown #4 wire is connected through the light bulb to 12V whenever the key is in the ON position. The other end goes through a set of points in the regulator and then out the F terminal to the field winding in the alternator. So some current begins flowing in the field winding from this connection. The little bit of current flowing produces a weak magnet field in the alternator and also lights the bulb.

When you then start the car, the weak magnetic field from above begins rotating which makes the alternator producing a little bit of voltage. This voltage is fed from the alternator to the regulator on the white regulator #2 wire. This wire connects to a coil in the regulator and turns on a contact when the voltage goes above 3.2V.

Once the contact turns on in the regulator the #3 and #4 terminals are connected together. Terminal #3 is battery power so this puts battery power on both sides of the bulb and turns it off. This means the brown #4 wire should go to +12V. Also, this connects the field terminal right to battery power but still going through the points.

When the battery voltage goes above a set level, the F terminal is disconnected from the battery power by the points I kept mentioning. Then the voltage drops and the points close again. This on-off cycling happens rapidly and is how the voltage gets regulated.

From the above (KOEO = key on engine off and KOER = key on engine running).
F or #1 terminal (field) - KOEO = #4 slight voltage, KOER = 9-12V typically
#2 terminal (sense) - KOEO = 0V, KOER = >3.2V
#3 terminal (Battery) - KOEO = 12V, KOER = 12V
#4 terminal (light) - KOEO = F slight voltage, KOER = 12V

By 12V above I mean battery voltage, which may be 12V when engine is off but could be up to 14.5V when engine is running.

Check the light: Ground the brown #4 terminal wire at the regulator. When grounded the light should come on. If you don't have a light then skip this test. Test this with the connector off the regulator.

Checking the alternator: Jumper the blue wire F terminal to the battery post on the back. This should make it easily crank out 16+ volts. Next, connect a troublelight between the battery post and the F terminal. The light should come on and you should measure > 3.2V at the other alternator terminal. If it passes these tests, then it's in the regulator or wiring.

Checking the wiring: At the regulator connector jumper the brown light wire (#4) to the F terminal (#1) and you should be able to measure >3.2 volts on the other alternator terminal or terminal #2 of the regulator connector. If these tests pass, it is in your regulator.

When doing these tests, make sure you turn off or pull the fuses for any added electronics that you can. The alternator test can produce enough voltage to damage stuff.

Peter

 

[Jim Mac]

did you check the voltage at the back of the alternator? I bought a rebuilt alternator that was bad. Fortunately I had it checked before I left the store, and since its was like 110* Im glad I had it checked before I installed it and found out it was bad. Jim

 

[Chuck]

BINGO!, We have charge

Way to go, Undee. You are always right on the money.

I got the car three years ago with no ground wire on the regulator so, I guess, it has never charged. Let's hear it for a great battery!

I removed the ground on the idiot light (uder side of the regulator) and grounded the regulator body and I went from 12.9 V KOEO to 13.7 V with the engine running. Actually, I feel a little dumb. Where the h*ll did I think the ground path was coming from for the regulator. You can make a circuit work without a ground somewhere and you can't burn out a regulator because of no ground because no current will flow.

Thanks Undee! Good job! I am now ready for a Summer of fun in California.

Best Regards
Chuck

 

[1Fast7D]

Re: BINGO!, We have charge

Thanks Undee! Good job!

I am now ready for a Summer of fun in California.

I have to "wait' for summer, there snow on the ground here.

 

[Chuck]

I said I was ready for Summer. I didn't say it was here. We had snow down to 2000 feet last nigh which, for California, isn't quite Summer.

Thanks again
Chuck