Odd overall voltage drop issue (With Video)

[OfnaRcR4]

I had this problem the other day with my car where i started it up and realized the battery was only showing 11.9 volts on my turbo timer and my idiot lights were on. I checked the battery connections and started the car back up and still the same issue. As i drove down the road i was looking at the voltage and as fast as you can blink an eye the voltage went back up to about 14.5. Well a couple days later here we are again at 11.9-11.5ish and it's not getting any better. I re-wired the alt directly to the battery hoping that would help but it didn't seem to help anything.
Odd thing. Battery voltage shows 12.3 or around there with key on, engine off and when i start it the voltage drops to the 11.9 range again. If anything it should be the opposite.
Help?

[video=youtube;NCSAI4TQwA4]http://www.youtube.com/watch?v=NCSAI4TQwA4[/video]

 

[OfnaRcR4]

Diagnosed. Was under the hood and decided to give the alt a tap and what do you know, it starts whining and i have voltage again. Brushes or comm must be spent or dirty. New alt on the way. Thought it was the alt but was just confused by the symptoms.