A few of us are using "the Saturn alternator." It comes from a 1991 Saturn SL and is available at Autozone with a lifetime warranty. It's output current is 96 amps, which is well-suited for the DeLorean's electrical system.
More details can be found here:
http://www.dmctoday.com/showthread.p...oltage-problem
Autozone part: DL1315-5-3
Pigtail connector: http://www.amazon.com/gp/product/B00...?ie=UTF8&psc=1