I think you answered your own question. New VR was over charging and old VR @ 12.4V isn't really charging. Should be between 13.5-14.
QUOTE(oakdalecurtis @ Jul 27 2016, 09:42 AM)
I installed a new alternator and a new Beru voltage regulator, started up my 76 2.0 and the charging system was sending 18 volts to the battery! Not good. I replaced the new Beru VR with an old Bosch VR, started up the car and now the battery is showing 12.4 volts at the posts, and the voltage doesn't vary a bit with engine speed. I think the 12.4 volts I'm reading at the battery is just the battery's own charge that I'm reading. How can I tell if this old Bosch VR, or any other future replacement VR, is actually charging the battery or not?