Low charge when hot.

[qkcuda]

I was having several intermittent electrical issues with my car which had a stock points type voltage regulator. I just replaced it on the weekend with a new solid state regulator, that looks just like the original. Suddenly most of my intermittent problems disappeared. That is the first thing I would change.

 

[RustyRatRod]

No, I don't have one.

No, I don't have a load tester. Best I can do is get the battery or alternator checked at an auto parts store. At idle I know the alternator would fail when the car is hot but pass when it's cool. I guess I could get another alternator since it's under warranty but I don't know if that would fix it.

That's where the load test comes in. It can determine which is at fault, the alternator or regulator. That is to say as long as you get someone who knows what they are looking at to check it out.

 

[LivewireBlanco]

I was having several intermittent electrical issues with my car which had a stock points type voltage regulator. I just replaced it on the weekend with a new solid state regulator, that looks just like the original. Suddenly most of my intermittent problems disappeared. That is the first thing I would change.

I may just replace it since it looks old as dirt and it about one of the last things that I haven't replaced on the car. It'd be easy to do and just piece of mind that it's new.

 

[Mattax]

His car came with a electromechanical positive controlling regulator.
Your car came with a solid state ground controlling regulator.

If its not working jumpering as discussed above will show that.
If it is working, keep your dollars for what does need fixing.

 

[pt70]

If it hasn't already been mentioned, remove and clean the back of voltage regulator to get a good ground. Sandpaper, star washer, and grease to prevent corrosion.

 

[LivewireBlanco]

Ok tested the field wire while running. 13.6 at idle in Park. 13.2 with lights on at idle. Couldn't test while in drive but that's where it drops badly. Voltmeter usually days 12 volts with lights on in drive. While driving it says 13.8 with lights on. I toughened the belt but saw no difference. I went ahead and replaced the voltage regulator but saw no change. Added a ground straight to regulator from the block and saw no change. Think the alternator is a little weak. Should I even let this bother me? With the lights off it usually charges in gear. Idle in gear is 750 rpm.

 

[67Dart273]

This really is starting to sound like the 'age old stocker Mopar charging system' in pretty much normal operation to me.

One other thing you might check, is to kick it up to fast idle, after it's run enough to normalize the battery. Stick one meter probe on battery + and the other on the alternator output stud. Turn on lights and heater blower. Se what it reads. If it's more than about 1.5V I would look for drop problems in the charge path to the battery.

This drop is not near as important as other measurements because whatever that drop is, the regulator will be "reading" the system voltage, and trying to jack it back up if the charge path drop causes the battery to be low.

But if that drop is more, say 3V or more, then it is getting to be an issue. Once again, the path through the bulkhead, welded splice, ammeter, back out the bulkhead, etc, to the battery. And if it's been bypassed, then whatever the bypass path consists of.

 

[LivewireBlanco]

This really is starting to sound like the 'age old stocker Mopar charging system' in pretty much normal operation to me.

One other thing you might check, is to kick it up to fast idle, after it's run enough to normalize the battery. Stick one meter probe on battery + and the other on the alternator output stud. Turn on lights and heater blower. Se what it reads. If it's more than about 1.5V I would look for drop problems in the charge path to the battery.

This drop is not near as important as other measurements because whatever that drop is, the regulator will be "reading" the system voltage, and trying to jack it back up if the charge path drop causes the battery to be low.

But if that drop is more, say 3V or more, then it is getting to be an issue. Once again, the path through the bulkhead, welded splice, ammeter, back out the bulkhead, etc, to the battery. And if it's been bypassed, then whatever the bypass path consists of.

Ok i just did this test and I got .8 volts from positive to alternator output. I guess it's just low output of the alternator at idle rpm.