The Stovebolt Site Forums The Shop Area The Electrical Bay AMP Meter

Hi all,
After restoring my truck I notice the AMP meter on my stock speedo system is acting like an earthquake Richter Scale. When I start up the truck and let it idle as well as driving it the needle shakes between the middle dot to the charge dot on the right of the display. I was told I need to polorize the regulator. Is this true and how do you do it?
Thanks!

Jon

seeing you've been running the truck for awhile, it's not likely to be your problem if you haven't killed the battery yet, but to polarize the generator [key off], touch a piece of wire momentarily between the Batt and Arm terminals on the regulator - it won't hurt anything to try

might also check all connections in the generator/regulator and battery circuit - and it could be a sticky regulator, try a sharp rap with a screwdriver handle while engine running [really ]

Bill

Hi Bill,
OK, I will give it a try. Yes no strange things going on other than that. I checked the gen and it was charging the battery and sending I think it was 14 or 15 volts back to battey.
Is the any grounding issues? The reg to the firewall? Gernerator? Things like that? Now a side note is, I re-used the regulator that was on the truck before the resto.

Thank you Bill.

Jon

yes, I'd think if it was charging the battery well then there's either something loose someplace [a ground or maybe a connection on the gauge], or else the reg itself is faulty - see if you can catch the sound of a relay chattering - good way is a screwdriver tip to the box and end of the handle against your ear

Bill

My gauge oscillates a lot too. For some reason it doesn't have any damping. My truck charges correctly and I just accept the gauge as is. Just turning on the ignition causes several oscillations on mine.

Hi Bill,
I could not hear anything with using a screw driver. Is it OK to run the truck with the black cover off the regulator?

sure it's OK, done to adjust the settings

Bill

IF the current is really fluctuating then so should the voltage. I think I would put a voltmeter on the battery. I would not use a digital but an analog so you can see fluctuations if any.

IF no fluctuations my next guess would be a loose conductor somewhere in circuit. OR a bad crimp - check for heated connections.

Could it be a load that varies ie windshield wipers (ah nuts I bet you have vacuum)

Last - is it just the nature of the instrument ie inadequate dampening of meter movement? I wonder what it would do if connected to teh truck but sitting on a separate bench. BUT I sure dont want to go to you and tear half a dash apart to answer my curiosity.

Uh this is a generator setup and not alternator. IF alternator could it be a shot rectifier?
Dan Bentler

Hey Dan
Good thoughts. I guess i question it as It never did it before. Its pretty much all the same parts on the truck. I do have another generator and regulator. I need to test Bills thoughts out. I might link a video to this thread so you all can see what it is doing.

Thanks!

Jon

Guess I would swap the regulator first and easiest.

Just a thought....could the ampmeter be wired incorrectly. As I understand it, the ampmeter is there only to show charge/discharge to the battery. If it is jumping around while other electrical things are going on then it might be installed incorrectly. The other posts about loose connections and such are spot on and need to be adressed. But like I stated...just a thought.

Before you swap the regulator, try increasing the tension SLIGHTLY on the points of the center unit, the current regulator. Some regulators have a screw to adjust the ternsion, others use a spring anchor that gets bent up or down. The unit directly behind the battery wire is the cutout relay which opens when charging voltage drops below battery voiltage to prevent discharging the battery when the engine stops. The center unit, behind the Arm. wire controls maximum current going to a low battery. This one usually controls current to a maximum of 25 or 35 amps, depending on which generator you have. The third unit, behind the "F" wire, is the voltage regulator. An erratic ammeter indication is usually caused when the voltage and current regulators try to operate at the same time. Only one unit at a time should control the field current, as they are wired in series with each other. Increasing the current regulator setting usually solves the erratic ammeter indication problem.
Jerry

Not sure if this would matter,,,,but for a time...I would leave the battery POS lead off. I did not trust the truck wiring just yet. Now I leave the lead on. Would that have had anything to do with it?
I have yet to do what you all suggested to do (no time).

shouldn't matter any more than using a theft-prevention disconnect switch

Bill