generx, I noticed that you posted the alternator was new. Was it really a FACTORY NEW alternator, or was it a "new" rebuilt alternator? If rebuilt, then it's bad. Sounds like the voltage regulator or worst, the diodes. Either way, that alternator (typically, they have warrantees) should have a warranty. I've had the same issues a few months after installing a factory REBUIL alternator. It came and went, then it went bad alltogether