Alternator Issue

[Mheiron]

So just took delivery of a 69 Charger and I’ve inherited the PO’s problems apparently.

The alternator is not charging the battery. I swapped out a new looking alternator with a O’reilly unit that worked fine on the tester and made 14.5v.

The voltage regulator looks like it was recently installed.

with the battery full at 12.7 volts the voltage at the alternator batt post is 12.4 and 11.4 at the field termina.

I tried a jumper wire from the battery direct to the field terminal but it still didn’t start generatin.

I like working on old cars but this one has me a bit frustrate.

Ill order a new voltage regulator but I’m not sure that will fix the issue.

Any input or ideas would be appreciated.

Thanks

 

[OH71RRunner]

Are you checking voltage at idle? Most alternators do not charge well at idle (under 1200 RPM). When you go to have an alternator in your car tested at places like autozone, they usually tell you to keep RPMs at about 2k.

When I'm looking at voltage on a running car, I always keep the RPMs above idle.

 

[Jerry Hall]

69 alternator should be a single field if it's stock. Most replacement alternators at parts houses will be dual field and will have to have the additional field grounded in order to charge.

 

[Mheiron]

So there are two field terminals And one wire from the regulato. I made a splitter to connect both field terminals to voltage.
Both terminal say “FLD”.
Maybe on termina should be grounded?

 

[Jerry Hall]

Keep your original field wire and ground the other.

 

[davek]

Alternator ground question.

Having charging issues. Got a new alternator from Layson’s. Has two field posts on the back. Is this the right style of alternator? Does one need to be grounded to the case for proper function? If so. What gauge ground wire to use? Points. Mechanical voltage regulator. ‘66 Charger.

www.forbbodiesonly.com

 

[Dave6T4]

Don't hook both fields to the VR. Ground one of them to alternator case.

 

[Don Frelier]

I would get the newer style solid state regulator and
Find the corresponding plug and wire it to the two terminals.

But yes you can ground one field and use your existing regulator as well.