Well, I had two different auto parts stores test my battery and alternator and BOTH places said my battery and alternator were FINE! They did say that the volts to the battery were exactable at 13.75, but I've read that optimally we need 14.4 volts. The tests also said my diodes were fine too. Still on a mission to fix my faulty NAV unit; and though those tests said everything passed, it is below normal in my eyes. So I think a "new" lifetime warrantied alternator is in my future.