Alternator not charging

Well got battery fully charged and had everything hooked up except the GRN terminal. Grounded the GRN terminal and still didn't charge. I also tested the Voltage at the Large black terminal of the alternator and at idle it was reading 11.3.

So I guess its an "internal problem". I do have a square back alternator that somebody gave me. So I will swap it out and see it that fixes it.