Greetings,
the regulator is in the alternator, so if you are using reman alternators there is a good chance that is the problem. If the battery is was going dead I would start by doing a draw test. Disconnect the negative terminal and place an multi function meter(set on Milli amps) connect it one probe on the battery terminal and the other the battery neg post. First make sure the door is shut and no hood light is on(pull bulb if there)ignition key off. You should have 40 or less milli amps of draw. If more than 40 try disconnecting fuses, if it is the alternator when you unplug and or power wire it will go down to less than 40.
good luck
ASE Master Technician & T2 diesel
28 years experience. Foreign and Domestic . Ford certified 05-06,Chrysler SC 06-08, GM certified 09