Polarization, not getting a charge

After switching the /6 to a 318, hooked everything back up, everything worked like it should. I put in electronic ignition, orange box from Mopar Performance, just a stock coil. Put in an alternator that i had used before on the /6, and not a new battery but one i had used on another car previously that still has lots of life.
The problem is: the car runs for a while and the Amp gauge shows the car is charging, but after a while it all of a sudden switches to decharging. So I switched alternators, and had a repeated scenario. Car charged at first, then later started to decharge. I heard someone mention once that if you unhook the alternator and other electrical things, you need to re polarize something after hooking them back up? does this sound at all familiar?
Author: admin