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Over-charging

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FrankH

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My 100M has been overcharging. I've tried two new voltage regulators, three different batteries, and the generator, which was throwing solder, has now been rebuilt. A couple of "experts" have told me not to adjust the voltage regulator becuase it was pre-set at the factory. I'm willing to adjust it, but what else could be causing about 15.5 volts to be showing at the battery?

Frank
 
Frank,

Have you used a multimeter/voltmeter to check this voltage or are you using a dash gauge?

Ian
 
Hi Frank,

How did you first experience the overcharge condition? Did you change or adjust anything prior to the condition? If the regulator senses a continuous draw/dead short, it will continue to provide full generator output to the circuit and battery. Has your battery been checked?

Good luck,
Ray
 
If you've replaced the dynamo and the regulator and the fault persists, then neither can be to blame and you have a wiring fault.

It's near impossible to diagnose from a distance but you could start by making sure that the D and F wires are not shorting across or the wrong way round.

I don't think you should run the car till you've checked the wiring against a circuit diagram or you'll possibly damage another dynamo.

Ash
 
I missed the 3 different batteries and in that case, I would suspect a dead short either in the main power circuit (brown wire) or extending from the main. I would tend to agree with Ash and would rule out the generator, regulator, or battery because of the multiple replacements. However, that would be after checking each as I have experienced multiple faulty regulator purchases.

If your generator is creating over spec, I would check the pulley size to validate that it is consistent with standard. A smaller pulley would cause the generator to create additional power at measurement RPM but should be controlled by the regulator.

Hope this helps,
Ray (64BJ8P1)
 
Run substitute wires to the regulator from the generator and the regulator to the battery/ignition switch and see if that cures it. If it does, then reconnect one of the two original wires and see if the fault resumes, etc. This way you can isolate the bad wire.
 
Thanks for the responses. Everythings seems to be connected correctly and I don't see any obvious shorts. Any suggestions for places to check? I think I have the original pulley which is about 3 3/4 inches on the outside. Does that sound right? I substituded the wires and that didn't change anything either. Any more suggestions? I will be out of town for a few days but need to solve this when I return.

Frank
 
Oh yeah. Ray, you said you have experienced multiple faulty regulator purchases. What were their symptoms? If I were to get another regulator, who would be the best source. Even though the ones I have are from different distributers, they seem to have come from the same source in England, I think.

Frank
 
Hi Frank,

I explored and went to an alternator out of frustration and a growing awareness of my Healey’s electrical circuit power demands.

I first experienced a low voltage output and found the regulator was at fault. Replacing the regulator, I, again, began to experience low voltage output a month after. Finally, after failing at trying to manually reset the regulator, I tried an electronic substitute which worked fine for about 9 months and then failed with low voltage. During all this time, the generator was checked out by at least 5 professionals.

I agree with your feeling that most distributors source replacement LBC components from a limited number of manufacturers and, chances are, you will acquire the same manufacturers component from multiple sources. My desire to break this pattern, and my growing knowledge of my Healey’s circuit power demands and risk, moved me to replace my generator with an alternator equipped with an internal regulator, install in-line fuses on all critical circuits, and apply relays to reduce the level of power passing through 45 year old components.

Hope this helps,
Ray (64BJ8P1)
 
Umm.....I'd have to pull out a wiring diagram, but in the old days of Autolite and Delco-Remy generators, a BIG problem was the ground wire from the case of the generator to the mount or ground lug on the regulator. If the grounds aren't right between the two, overcharging is a definite probability.
 
The suggestion on the ground wire is your most accurate cause for over charging. If the regulator cannot sense the voltage correctly due to high resistance in the ground path it will continue to ask the generator to increase. Note that there should be a heavy ground braid from the bellhousing to the frame that is intended to keep the ground path secure. Also, polarize the regulator per the instructions packed with the new regulator. Pulley diameter does not enter into this at all, it seems to only be a wiring problem as stated.
 
A couple of "experts" have told me not to adjust the voltage regulator becuase it was pre-set at the factory.

Wellthat was usto was. The reasion you can not purchase a control box with your original number on it is the factory no longer calibrates them to a specicific generator.



I'm willing to adjust it,

Great!!! have ago at it and let us know how you made out.--Fwiw--Keoke

but what else could be causing about 15.5 volts to be showing at the battery?
-under the circumstances presented I think nothing else is wrong. :nonod:

--------------------------Keoke-- :driving:
 
Hi Frank,

I appreciate the frustration you must be experiencing, however, let me tell some of the dumb things I have done. When thinking my Optima battery was being overcharged at 17+ volts, it turned out to be a low battery in my multi-meter. When finding low voltage only when the engine was hot, it turned out to be a non-squealing, but slipping, fan belt. When finding a low charge indicator glow when driving, it turned out to be a spot of paint on the regulator ground terminal.

Although these may not apply, I thought I’d mention them in the chance that something would click.

Good luck,
Ray (64BJ8P1)
 
Thanks for all the help. I took the generator off and made sure all the ground contacts were good along with the battery, frame to engine, etc., etc., etc. I bipassed the battery switch and did everything else to look for bad grounds or faulty wiring. Even though it didn't make sense to keep throwing the same new parts at it, I decided to try one more (pre-adjusted) voltage regulator from a third source. This one is spot on! Of course I now wonder if I should have just adjusted the others.

Frank
 
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