One more test. Take the wire off the "f' terminal on the alternator and tape it. Take a scrap piece of wire and put it on the "f" terminal of the alternator, and lay it near the battery. Get the engine started, and put your meter on the battery terminals. Then touch the scrap "f" wire to the bat + terminal. The voltage should jump up, and you may hear the alternator start whining and the engine load down a little bit. That means the alternator is good, and I would replace the regulator. Putting 12v on the "f" terminal throws the alternator into wide open charge.