The Stovebolt Site Forums The Shop Area The Electrical Bay 12V conv w/someone else's wiring - ammeter help

Hello!

A few weeks earlier I posted about my 12V conversion w/someone else's wiring job. Thanks to all for their help.

Here's where I am...A 10ga red wire now goes from the starter/batt terminal to the back of the ammeter (right hand terminal, looking at front of the meter). The other side of the ammeter now has 3 leads, 1 going to the ignition switch, one to the light switch, and one to the batt terminal on the 12V voltage regulator.

The truck starts, all the lights work, signals work, everything appears to be in order...BUT...
The ammeter doesn't move at all when I start and run the truck, run the lights, etc. NOTHING...not even a jiggle, no matter what I do.

Yes, I did polarize the new voltage regulator by bridging the batt and arm terminals for about 2 seconds.

How can I tell if the ammeter is bad? I know that it's supposed to show a slight discharge after starting, then slowly move back to center as the voltage regulator does it's thing and allows the battery to charge, and move a bit toward discharge when I'm operating an accesory. It now looks like its glued in place, so I'm pretty sure it's not working.

Any advice?

Thanks...

Chris

Try turning on as many accessories as possible with the engine not running- - - -high beam headlights, ignition switch "on", electric wipers if it has them, cigarette lighter, heater blower, etc. The ammeter should swing almost full scale to "discharge". Leave the drain on the battery for 5 minutes or so, then turn everything off, start the engine, and accelerate to fast idle. The ammeter should swing at least halfway to "charge", possibly more, depending on the capacity of the generator and the current regulator setting. If the ammeter doesn't move under these circumstances, you've probably got a bad meter movement.
Jerry

What does the needle do when the lights are on with the engine not running? Is the output lead of the generator also connected to the 'bat' terminal of the regulator?


The above statement is incorrect. When working right the gauge will show a charge immediately after starting then taper off as the battery builds back up. When an accessory, like the lights, is turned on while the engine is at operating speed there should be a momentary reading of discharge then the regulator should provide enough amperage to operate the lights without any draw on the battery. At idle it will probably show a discharge.

Jerry/Cletis -

The ammeter shows NO movement no matter what I do, engine running or not. I've turned on the lights/blinker/heater with absolutely no movement from the Ammeter.

Cletis - Thanks for the clarification on ammeter reading.

Is the "F" (field) terminal on the generator the output?

There is one wire from the harness attached to the Bat terminal of the regulator. I can't tell what may be attached to it inside the harness.

What is the routing of the output wire from the generator supposed to be?

Sorry if the answer is obvious, but all this is new to me.

Thanks...

Chris

Barsteel -

Don't do the following until Jerry or Cletis or someone else with good knowledge of the ammeter confirms my idea..

Looks like you could test to see if the the ammeter works by disconnecting all wires from the gauge, then ...
> Connect a wire directly from the positive "+" post of the battery to the ammeter terminal that is under the "Discharge" label.
> Connect a tail light bulb or similar load to the ammeter terminal that is under the "Charge" label.
> Briefly touch the ground side of the bulb to ground.
If the ammeter is working, the needle should deflect.

Good luck.

The wire attached to the Bat. terminal on the regulator should go to the ammeter, to the same connection where the ignition, lights, and other wires are attached. Have you checked the voltage at that terminal? It should read battery voltage at all times with the engine off, and should increase to 13-14.5 volts with the engine running. The voltage at the positive battery cable should be the same reading as the regulator Bat. terminal, minus a few tenths of a volt for losses from connections in between. Is there a heavy wire in the harness near the ammeter that hasn't been attached yet?


Here's a schematic from a Delco service bulletin book from the early 1950's. The wiring will be the same for both 6 and 12 volt circuits. Looking at the diagram, the wires to the ignition switch, headlights, etc. would be attached to the right side of the ammeter, same place the regulator Bat. wire attaches.

http://www.hunt101.com/data/500/D-R_Regulator_001.jpg

Jerry

Jerry -

That's exactly how I have the connections set up...there are 3 wires attached to the ammeter (opposite the lead coming directly from the battery) - one going to the Bat terminal of the voltage regulator, one going to the light switch, and one going to the ignition switch.

I was a bit confused by Cletis' asking me if the output wire from the generator was attached to the Bat terminal of the Voltage regulator. There is only one wire going to the Bat terminal on the voltage regulator, and that's a 10 ga red wire from the ammeter. As far as I can tell, there is no connection between the output wire of the generator and the Bat terminal of the voltage regulator.

Chris

The Armature wire is the generator output. It's connected to the Bat. terminal through the cutout relay inside the regulator. That relay only closes when the armatuire voltage rises above the battery voltage to keep the battery from discharging backwards through the generator.

If you're connected like the diagram shows, the ammeter should be deflecting both ways. It's possible you've just got a bad meter. Is the voltage going up at the battery terminals when the engine is running and the cutout relay is closed?
Jerry

Ok, I qualify for moron of the year with this one. Checked the leads to the ammeter, and found that I had mislabeled the one directly from the battery. Put that wire on the right side of the ammeter and the 3 leads on the other, and the ammeter now works.

I started to button things up, and when I was pulling myself up from under the dash, the ignition switch retaining ring slipped out of my hand and fell behind the gas tank...but that's another story.

Chris

Having the same issue. The battery and hot wire to the voltage regulator are connected under the "D" side or under the "C" side?

Check this diagram:

http://www.hunt101.com/data/500/D-R_Regulator_001.jpg

There should be only one wire to the battery side of the ammeter. Every other connection including the battery wire from the regulator needs to connect to the "load" side of the ammeter for it to function properly. The simplest way to figure out ammeter polarity is to connect the wire from the battery or the starter cable to one side, connect all the other hot leads to the other terminal and turn on a bunch of accessories. If the ammeter needle swings to the "discharge" side, you're connected properly. If it moves toward "charge" with the engine off and current flowing, swap the leads side to side.
Jerry