The Stovebolt Site Forums The Shop Area The Electrical Bay generator/charging issues

recently replaced the 6 volt voltage regulator, new "used" brushes on the generator, cleaned up all the contact leads and ground wires and patched any frayed sections of wire.

normally the meter would drop to discharge while sitting at a light but would then wind up to show a charge when the engine rpm's came up. i had the generator checked on a test bench and everything was working great.

yesterday i noticed that the amp meter in the instrument panel was showing a discharge even while i was cruising. according to the repair manual this indicates a fully charged battery. the only thing i noticed though was that at certain times the meter would jump to the charge side only to fall back to the discharge side when i would come to the next traffic light.

short story long, i guess my question is does this sound normal or is there still something wrong with the charging system? if something is wrong, whould i look at the voltage regulator again or is there another area i should investigate?

any and all advice/opinions are welcome.

Turn the lights on. The amp meter will drop to discharge. Acelerate the engine a little. The amp meter should go to the center or further. With the engine off turn on the lights for a minute or 2. Sart the engine & accelaerate it. The gauge should go to charge for a while & slowly go back to center. It,s a good idea to buy a little volt/ohm gauge for about $10. Hook it across the battery terms & it should read about 7 to 7.5 volts when you accelerate the engine. Make shure everything is grounded. Engine to frame, frame to body, & voltage regulator.

p.j.

I always thought if the ammeter was showing a discharge, then that is what the system was doing. If your battery is fully charged, and you are driving the truck, the lowest the meter would indicate would be 'zero' charge. If it is less than that, your 'amps' bank account is being overdrawn.

Did the system act the same with the other regulator?

It is sometimes recommended to polarize the generator if it has been removed from the truck..this quick procedure certainly couldn't hurt.


Stuart

generator has been polarized and the battery has a full charge. wires are all grounded with clean connections.

at speed with no accessories turned on the amp meter hangs just under the 0 mark. turning the fan on and/or lights drops it well into the discharge no matter what engine rpm is.

when i first had everything back together it behaved as described (engine rpm increases, amps increase and then level off). now it seems the needle just "sits" there no matter what the engine speed.

i'm going to put the volt/ohm meter on the battery this after noon and see if the charge is making it that far. i already checked the generator while the engine was running and it seems to be fine. if the battery isn't showing a charge rate then i guess i'll go back to the voltage regulator again.

thanks for the advice guys!

p.j.,

The ammeter is between the generator and the battery. If the ammeter is working properly, and doesn't show a charge, then you can be assured the generator is not charging the battery.

I have pasted a HRL quote. This will help isolate a generator problem from a regulator problem.


"Attach a ground wire from the field terminal on the generator to ground. This should put the generator into full output if it's able to charge at all. If the voltage at the armature terminal doesn't rise to above battery voltage with the field grounded, you're going to need to rebuild the generator."


Stuart

i understand what you are saying atmarc, but if the regulator, being between the generator and the ammeter, was bad, couldn't that also be the problem?

i think i'm just going to pull the generator again and have it tested (again). if it is still working properly then my next step will be the voltage regulator.

most of the "tests" that i did with the time i had today indicate that there is not a charge getting to the battery at all and from what i can tell, it seems the generator isn't putting out as much juice as it should. my volt/amp meter is a bit confusing at times or maybe i'm just not as smart as it is.

thanks again for the advice.

I think this should read "disconnect field terminal from regulator and momentarily touch it to ground." Have someone watch the ammeter while you do this. It should read full charge. You don't want to run like this for long so I wouldn't recommend "attaching" a ground wire to it.

Good point Cletis. I think the idea of ' momentarily ' touching a wire from the generator field terminal to ground was to take any wiring issues out of the equation.

If you pulled the field wire from the regulator and touched it to ground, and saw no increase in generator output, the assumption would be a bad generator... the reality might be a broken field wire from gen to reg!

Stuart

Good point, atomarc. The next logical step would be remove the generator end of the field wire and ground field with a separate wire.

Good point Cletis, I think someone mentioned doing just that!


Stuart

The jumping ampmeter would lead me to the regulator.

I'll have to agree with Chester... especially since it was mentioned that the Gen already passed a previous bench test. If it worked on the bench but is questionable in the truck, start looking at the regulator and the battery.