Here's a video of some weird voltage fluctuations: https://www.youtube.com/watch?list=U...7UOj9-pqU#t=83

The drop is accompanied by a revving sound and the car is overall quieter. The return to 14 is accompanied by a low rumbling. When it's running normally at 14, I get a reading of .16 with the positive electrode of a voltmeter on the negative battery terminal, and the negative side on the outside case of the alternator. However, when it's dropped down to 12, I get a reading of 0 with this same test.