Sanity check for charging system

[Potshot]

I have about a week before I'll need to put my 67 Charger 440 in storage and and there's something that's been bothering me that I'd like to sort out before I do this. I have yet to see a charge greater than 12.37v out of my alternator.

Before I acquired the car it was retrofitted with a pertronics ignition, the ballast resistor was taken out of the system as part of that and otherwise runs well.

I've checked/cleaned all of the grounds I can find, and with the key on, the voltage regulator shows 2.03v

(I put the negative probe against raw steel on the inside of a hole, other places too))

Checking from the alternator positive to a ground the measurement is the same; 12.19-ish at idle, throttling it up gives me 12.37 at best. As a sanity check I grabbed the reman alternator from RockAuto that is the same round back style and I get the same numbers.

The car is a hobby, I'm not a mechanic and I'm even less of an electrician lol, and with no gearhead friends around I'm stuck reading posts and watching YouTube videos for information. I started looking into this when troubleshooting my headlights and someone asked if the headlights would open when the car was running and whether or not I was getting a full effort from the alternator.

Are there other tests I can run to check to make sure that the charging system is doing what it should? This seems like it should be fairly simple, but I'm clearly missing something. I've recently charged the battery up, is it possible that the alternator would not put a 13+ volt charge to the battery if it didn't need it?

Thanks!

 

[pnora]

You can full field the alternator. Unplug the field wire and with the car running jump 12 volts from the battery positive to the alternator field terminal. See what the alternator puts out as you rev it up. If the alternator is working you should hear it load down.

 

[tonysrt]

Since you didn't say anything about the regulator that also has a lot to do with limiting voltage, did you replace it? Voltage should be at least 13 volts to charge battery. After a start the alternator would put out at least 13 -14 volts because of the starting drain on the battery. Have you tried another voltmeter to make sure of the volts you're reading? I've seen 2 of the same brand voltmeters get different readings.

 

[Potshot]

Thanks guys, good tip and advice. I'll see what happens and post back.

 

[Don Frelier]

So you store your car starting in March?
It get's too hot to run it?
Sorry just curious.

 

[Potshot]

Several projects, limited space and insurance requirements for classic coverage. Yes, summer heat and hurricane season do play into this somewhat.

 

[Don Frelier]

What does the ammeter show:
1. Just after you start it
2. If you raise the RPM
3. If you turn on the lights or press the brake
A. at idle
then
B. if you raise the RPM

Do you need to put it on a charger after running it or will it start fine everytime?

 

[Potshot]

I only had a minute at lunch to take a look at this, but with the field unplugged at the alternator and a number 6 wire connected from the positive side of the alternator to the positive side of the battery, I'm still not getting much in terms of a charge; 12.17, and not much more when I give it some gas.

Is the general consensus that my new alternator is just as lame as my original? Is there anything else that could be playing into this? It seems fairly cut and dry.

 

[Potshot]

....a different multimeter yielded similar results.

 

[pnora]

I only had a minute at lunch to take a look at this, but with the field unplugged at the alternator and a number 6 wire connected from the positive side of the alternator to the positive side of the battery, I'm still not getting much in terms of a charge; 12.17, and not much more when I give it some gas.

Is the general consensus that my new alternator is just as lame as my original? Is there anything else that could be playing into this? It seems fairly cut and dry.

The jumper was supposed to go to the male spade field terminal.

 

[Potshot]

Ugh, ok thx. Reading is fundamental.

I'll try that again in a bit.

 

[Potshot]

The jumper was supposed to go to the male spade field terminal.

Oh wow, 16.4v

Voltage regulator?

 

[pnora]

Oh wow, 16.4v

Voltage regulator?

Could be. Unplug the regulator. One wire should be keyed 12 volts. If there is 12 volts than it most likely is the regulator.

 

[Potshot]

I had a spare VR waiting in the wings.

Thanks for the help, I expect someone else will also eventually benefit from this thread.

 

[tonysrt]

Might have been the regulator all along and not the alternator.