Verifying charging system on 6V Alternator system
 

Just got my new 36 Pickup going and it appears to have been restored bone stock with the exception of a 6V pos ground alternator.

I am charging the battery since it seems to be really low. I would like to do a quick check of the charging system to see if she is functioning correctly.

Before I charged the battery I was still be able to barely (turn over slow) start the car, and then the stock ammeter would read a hair below 0 when running lights off, and dips to neg 5 or 10 with lights on. Is this what I should expect? I thought with the alternator it should maintain near zero with the light on? My assumption is that the alternator has a voltage regulator, but not sure? I think it's a one wire setup

Re: Verifying charging system on 6V Alternator system
 

It all depends where the ampmeter is connected, if its connected in line to the battery, you have a problem, ammeter will show charge or discharge whether its a generator or a alternater. If its hooked up backwards it will show discharge when charging. Turn on your lights with the engine off it will discharge if its hooked up right.

Re: Verifying charging system on 6V Alternator system
 

The ammeter shows discharge when lights are turned on with the engine off so should be ok.

Anyone have any suggestions as to quick ways to verify if the charging system is working?

Re: Verifying charging system on 6V Alternator system
 

Put a volt meter on the battery while running and should read 6.2 to 6.3 v

Re: Verifying charging system on 6V Alternator system
 

Should be charging about 7.2 volts at the alternator (and at the battery with only a very small loss between them.)

Re: Verifying charging system on 6V Alternator system
 

Hi there, The main battery wire on the alternator is connected to where at the other end ? Is that wire the original one that connected to the generator or a new wire that was fitted with the alternator conversion ? It might be charging the battery but not actually connected through the ammeter and therefore not reading a charge. With engine revved up above 2,000 RPM the voltage reading across the battery terminals should be approx. 7 volts to 7.4 volts if the alternator is working OK. Battery voltage at rest fully charged should be 6.3 volts. Your alternator would have a built in electronic voltage regulator. It is most likely a Delco alternator. Is it a single wire or a three wire connection on the Alt. ? Regards, Kevin.

Re: Verifying charging system on 6V Alternator system
 

Thanks for the tips, I tried checking the voltage of the battery with a digital volt meter and as soon as I touch the GND lead of the meter to the GND post the meter goes crazy.

I guess I need an analog meter to do this verification while the engine is running?

I have a Schumacher BT-100 100 amp Battery Load Tester coming in the mail tomorrow so I think that should work hopefully?

Re: Verifying charging system on 6V Alternator system
 

I think you want around 7 volts from the alternator to charge the battery. If your meter is going "crazy" when you check for direct current voltage perhaps your alternator has a bad diode, regulator, or you have a grounding problem. Try checking for alternating current from the alternator. In this case, AC bad, DC good.

Re: Verifying charging system on 6V Alternator system
 

How do you check at the alternator with the one wire setup? One meter lead to the wire, and the other to the body of the alternator?

Are you proposing actually checking the alternator to see if it reads AC? I have never heard of this