electrical demons

volt meter started to read 10 volts and drop down to 8 w/lights and accesories. stupid me didn't trust my brand new AutoMeter gauge because I had a ground problem earlier. Well woke up with a dead battery.
Charged my battery started right up and now volt meter reads 12.x at idle and over 14 at higher rpm's.
what gives, can an alternator or voltage reg start to go out; or could I have a short or something in my wiring. I did the re-wire myself ala MAD electrical suggestions. The alt is one of those low amp stock type with a transitorized voltage reg. If I wanted to change to a 75amp Powermaster w/ an electonic Mopar Performance reg what would I need to do. That volt reg has a triangular looking plug, where would I get that harness. I did see some old post that someone had schematics, if anyone could post any ideas or send schematics; I would greatly appreciate it. [email protected]