New alternator and battery but battery still won't charge in my ford explorer 93?

My battery wouldnt charge So i just replaced my alternator a few days ago knowing it would fix the problem. It appears that the alternator was not the problem. I've got a brand new alternor and when i check the battery(running car), it just stays on 12.5V and doesn't go up. I tried using it yesterday and it just drained out on me. I tried 3 good batteries already and checked if they charge in my car but they don't. Oh, the alternator came with a volt regulator.

Hi so as you went down the POKE and NO HOPE route time now to take it to an auto electrician.