Overcharging

Overcharging is VERY often caused by voltage drop in the ignition harness, if it's just a "bit over."

How bad is it? What voltage is the battery running, and is the ammeter pegged at higher RPM?

Generally, in no particular order:

1....Severe overcharge/ over voltage caused by field grounded on green wire (regulator) circuit, ether bad regulator, grounded green wire, or broken insulator in brush holder.

2...Bad voltage regulator

3...Bad battery or maybe it is just way down on charge. Charge it up (battery charger) and have it tested

4....Voltage drop problems. There is a LOT of this in these old cars. This is usually in the harness, but can also be because the VR is not grounded to battery potential

So.........if voltage only runs a little high, like 15--16V, and not severe, and if you think the battery is OK and charged, run these tests:

A....Turn key to run with engine off. leave all wiring connected. Connect voltmeter (back probe connector on field blue or at ballast---and stab other probe into the battery POS post. You are hoping for a very low reading, the lower the better. Much over .3V (3/10 of one volt) you need to investigate.

The functional path for power to the VR is .....battery---to starter relay "big stud" through fuse link.......through bulkhead connector (big red ammeter) to and through ammeter.....out on ammeter black........to welded splice (under dash) to ignition switch connector....through switch........back out connector on blue "ignition run" .....back through bulkhead connector...........and to underhood "run" loads, ignition, VR, alternator field, etc.

All of the points listed above can have a bad connection and cause volltage drop

B:..GROUND SIDE: Run these tests with engine warm, battery charged "normal" and at high idle to simulate med--low cruise speed RPM. Measure first with all accessories off, and again with headlights, heater, etc running.

So with engine running "fast idle" stab one probe into the mounting flange of the VR. Stab hard to get through paint, rust, etc. Stab other probe into top of battery NEG post. As in the first test, you are hoping for a very low reading, zero is perfect. If you get .2--.3V or worse, Clean VR mount and bolt holes, remount with star lock washers, and improve battery jumper to body