Alternator not charging the battery properly?

Hello, and thanks for your question!

Does the red battery light come on the dash? I ask because there is a circuit just for this mechanism by itself and could also be a clue. In the meantime, you may need to charge the battery prior to 12.6 volts and start the vehicle and read the voltage at the battery, it should be at least 14 volts.

If in fact the battery is being drained while running then the engine is running solely off the battery and not the alternator, or the alternator charging circuit has a short to ground somewhere. I will attach the wiring diagram for the starting / charging system below. Check ground connections at the generator, some of them ground themselves on the case and others on the bracket it is bolted to. But first, I would to know the battery voltage with the engine running.

Please let us know,
William