What is the ammeter supposed to be showing usually? Mine is generally very near the high end of charge, sometimes coming down to about half-way on the charge side. Drove about 40 miles today, didn't really change much. If I'm not mistaken, it should be closer to the middle?

True it should be close to middle.

Did you add any accessories like electric fans, high amp stereo, or other power accessories? If so they should be between the Alternator and the ammeter not between the ammeter and the battery. If they are hooked up to the battery side then the alternator is powering them through the ammeter and it will read charging all the time.

First make sure the ammeter is working semi-correctly.

Ignition off should be at center. Hit the brakes it should drop to below center. Turn on headlights on also and it should drop farther.

If it isn't reacting correctly it could be the ammeter.

Next charge the battery completely off the car and test it. When you start the car it should be near center.

If not and the added accessories are on the alternator side of the ammeter it is probably the voltage regulator overcharging. A VR overcharging can kill the wiring harness just like a short can. Test the Alternator and replace the VR.

Hope it helps.

Definitely overcharging. check that the VR is grounded & the plug in connector tight & if so replace it

I believe this same thing may have happened before. The situation I described is with a new alternator and a new voltage regulator. Also new battery, new wiring harness. Bulkhead and ammeter connectors look good. VR grounded. No accessories at all, not even a radio. Engine and factory lights only. The one suspect item is the connector on the fusible link is slightly melted. I need to look at this better to verify the connection.

Sounds like maybe I need to look for high resistance somewhere...?

I was just having this same problem on my car. It was actually boiling some liquid out of the battery caps on my original style battery. The amp meter was showing a high charge while I was driving. I thought it was a stuck votage regulator but after taking my battery out to have it checked, I found out the battery was shot and therefor continuing to call for more charge from the system. Just something to think about.

The problem is solved. I worked on the melted fusible link connector. It wasn't making good contact. I corrected this, and then started the car. The ammeter reads almost full charge for about 30 seconds, 4-5 lines to the right of center, then starts working it's way down. After a couple minutes, it's at one line to the right of center, slight charge. Also, it is now mostly stable with throttle input. Before, it would fluctuate greatly with the throttle. Thank you for all your help.