I doubt it's the alternator
Where are you reading the battery voltage? On your electrical panel or on the instrument panel? Dose the key have to be on to read the voltage? Did the new battery read 10 volts? Did you run the engine and check the voltage while running?
While cranking the voltage will drop, as the alternator is not charging at this point and the starter is drawing allot of current. Most alternators will not start charging until they get to a certain rpm. For sake of argument about 1000 engine rpm then once excited will continue charging even at idle. When the alternator is charging and the engine reved up a bit you should be seeing around 14 volts.
Last edited by capn_dave; 10-10-2006 at 06:46 AM.