You mention that the ammeter "constantly reads charge" when you start the engine. Does it continue to read charge even after the battery is fully charged back up?
If it does not settle to center once the battery is charged, it seems like you have the wire from the battery and the wire to the light switch connected to the wrong ammeter terminals. Just switch those two on the ammeter and see if that fixes the problem. Leave the wire from your regulator connected as you have it.
Mark
