VCCA Home Forums TECHNICAL - 1945 AND NEWER 1949-1954 Need amp/voltage gauge wiring help!

Hey All, hopefully someone can help me out with this question. First some background. My car is a 1950 Chev Fleetline which I've almost finished completely rewiring and updating to 12 volts. For the time being I am running an alternator. I've been using an American Autowire kit which has been very straightforward and user friendly, however I've run into one small area of confusion concerning the amp/voltage gauge. Firstly, which post is positive and which is negative? (when looking at the back of the gauge) Secondly, does the positive post receive the power wire run inline with the gas gauge (the only other electrical gauge) and the negative post a ground? Or does the gauge get wired inline with the wire oing from the alternator to the starter? Or have I got this completely messed up? I know that from the wiring diagram in the workshop manual there are many more wires when using a generator/regulator system and that's why I'm confused on this. Any help is greatly appreciated!

Need to know if you are running a single wire alternator and then answers will be provided.

Ray, I'm pretty sure it's a 2 wire alternator, but I'd have to check tonight to be absolutely sure. I know the kit I used included the DA plug to turn the engine off. I don't know if that helps?

Hi mark50,

Too bad it was not equipped with a single wire alternator. Makes life so much easier.

Now, to your main question. The wire from the battery goes to one of the terminals on the back of the amp meter. The wire from the alternator goes to the other terminal. (Side thought. If you have a voltage regulator external for your alternator, the terminal on the voltage regulator marked Btry or (+) will go to the amp meter) With everything now connected turn on some accessory such as the dash light, and see which way the needle moves. If it moves toward the (-) side of the gage, turn off the lights and pore a cool one. If it goes toward the (+) side of the gage, hold off on the cool one until you reverse the two wires on the back of the amp gage.

Thanks Ray! I checked things out last night, read some more wiring books and came to the same conclusion, but it's nice to get confirmation too! So thanks again.

Hi Ray,
I wired the ammeter between the alternator and the battery terminal on the starter solenoid, with an 8 gauge wire. When the ignition is turned on the needle stays in the middle (no discharge or charge) but then it snaps all the way down to the discharge side briefly before returning to the middle. Now with the car running, headlights on, high beams on, and wipers on, the gauge still stays in the middle. I can start the car with the headlights on and it doesn't affect the gauge. With the ignition on accessory, lights on, and the car not running the gauge stays in the middle. So my question is: is this normal? Is my gauge messed up? Or is my battery charged to it's maximum and everything is fine? Keep in mind that the car has barely left my garage in 2 years (regrettably) and that the battery is about 8 months old so has hardly worked at all.

I need more information on the exact terminal you used on the starter solenoid. Did you connect to the large terminal that leads directly to the battery or did you use the terminal that activates the solenoid.

If you connected to the large and heavy wire directly to the battery, then your amp meter should reflect any debit or credit to or from the battery. If it doesn't, suspect the amp meter, or the wire is not connected correctly.

Ray, the wire is connected to the large battery terminal on the solenoid. Originally this 8 gauge wire came from the alternator directly to the solenoid battery terminal. From what I read in previous posts and books, the ammeter was to be inline with this wire. So that's how it is wired right now- one side of the ammeter connects to the alternator with the 8 gauge wire and the other side to the battery terminal of the starter solenoid. I have a spare amp gauge so I think I should wire that up and test it out. What do you think?

Hi mark50,

The next thing to check is to insure that the "load" (everything but the battery) is connected to the terminal on the amp meter that goes to the alternator. If the load is placed on the BATTERY side, you are in effect bypassing the amp meter.

If you get ANY reaction from the amp meter it is a good bet the meter is A-OK.

Ray thanks for the reply. So are you saying there should be another wire connected to the amp gauge on the alternator side? Because I have another heavy gauge wire that also runs from the battery terminal on the solenoid to the battery terminal on the ignition switch and then feeds the fuse panel. Should this wire run to the amp gauge too, before it runs to the ignition switch? And if so does it connect to both terminals on the amp gauge so the amp gauge is inline?

Hi mark50,

AH HA!, now we have the solution. To one side of the Amp Meter, connect the wire from the starter solenoid. To the other side connect all appliances that require power (ignition switch, and any item that requires power with the ignition switch OFF) AND the wire from the alternator. Turn on any device (ignition switch for example) and the meter should move and to the discharge side. If it moves to the right (charge) side you must move ALL wires to the opposite terminal on the amp meter.

That should solve all your wiring problems.

Thanks Ray, I'll give it a try and let you know how it goes!