I had a bad alternator - replaced it and also replaced battery...drove the car a couple of times - long trips non stop for a about 45 min...I come home and shut off car - won't restart - have to charge battery...batery fully charged - reads only 12 volts with car running...battery is new, alternator is new and bench tested - working, starter is new too....am I missing something, could it have been a fluke that the battery was so low before with old alternator that it never good fully charged? If a battery is fully charged should it only read 12 volts with car running?
I don't have air or a radio in the car.
Please help

How many volts do you read off the back of the alternator? Measure the alternator's large red wire to ground.

what shold it read? should it be the same as the battery?

<BLOCKQUOTE>quote:</font><HR>Originally posted by 69CHVL:
what shold it read? should it be the same as the battery?<HR></BLOCKQUOTE>

Higher than the battery. 13.5 to 14.7 volts.

Haven't checked yet John..but will....if its higher what will tell me...if the same or lower?

If the voltage is higher than the battery, that is, in the range I mentioned: You have an open wire or a poor connection somewhere between the alternator &gt; horn relay&gt;wire block&gt; battery.
If the voltage is the same, your alternator is not working.