Ok all, pulled and dropped off my Alternator at the shop that rebuilt it. I told him that I tested it with a volt meter the day I installed it and it showed around 13.5 volts. I then told him all my other cars show an average of 14.5 volts. He said this is true, but the BMW has the battery in the rear of the car and this is why it is 13.5 volts.

Is this true? Can someone please take a volt meter to their battery post while running and take a reading?