69 Dart GTS 383 4 Speed Completely Original

Does it ever show a substantial charge? EG you start it up, so the battery has been "used" a bit, with nothing on, it should jump over to charge "someplace" and taper back to the middle as the battery comes up.

At this point it's hard to say.

1...Go back to the first. Take a jumper wire, and unhook the green field wire at the alternator. Hook from the alternator field over to the alternator output stud. Run it "carefully" that is don't get crazy with the throttle. The more RPM, the more it should charge. It might not 'keep up' that is, might not show a positive charge at low RPM, idle, but "just above" curb idle, IE "fast idle" it should keep up with heater and lights in the "positive zone."

If it does NOT, hook your voltmeter to the battery, run it with lights and heater, and gently bring up RPM. At a speed "about" low cruise, IE 30-35 in high gear simulated, read battery voltage and post back

Next, move your voltmeter over to the alternator output stud and do the same thing. Post that reading.

Finally, disconnect the jumper wire, and hook the green back up "normal," and take a reading under these same conditions at the battery.

I'm thinking............

Either the alternator is actually not outputting the full amount, meaning it's defective,

Or there's a real bad connection in the charging wire between the alternator stud, through the harness, and to the battery.