[RICK LAKE]

zzmac I have heard more than once about these optima batterys having internal shorts on 1 cell and killing the Alt diodes in the regulator. 13.5+ volts is not enough to running all your systems and and charge the battery. It sound like only 1 of the 3 legs in the alt is still working. Are you sure that the Alt belt is not slipping on the pulley? The belt is not glazed? You have no charging after your short road test. As far as trying to start the car with another battery, what is the voltage on that battery? 12.5 or high would mean you have a good battery but you could also have low CCA cold cranking amps. How many grounds are on the car? How many go from the frame of the car to the battery? Where is the battery located. I would remove, clean the mounting area to the grounds and reinstall. If you strip the contection, this will cause the same problem. With everything hooked up, can you twist the battery connections? If yes, this is a problem. If not, go to the batery cable other ends and test and clean them. Do you have under driven pulleys on the motor? If all checks out, Do the Pepboys or Autozone thing. May sure you go to 2 different places. I believe your battery shorted and cooked the Alt. Road test your car with your volt meter hooked to the battery and have someone hold it or tape it to the windshield for this test. If you see the voltage fall with the mustang battery, the Alt is cooked. Rick L.