Mine died and won't re-charge anymore... wow... Push startin' that pig isn't all that fun either, as you guys know.

Scott

 

tinman650,
What JSsDS posted is right on. But in addition the voltage regulator has to have the ability to "sense" the battery's state of charge and reduce the charge rate accordingly. There is also the need for properly functioning diodes in the system to make sure the power only flows one-way. Although there is most likely a test for the regulator, I don't know what the procedure is, beyond what you've already done.

I'm in the automotive field and when we get to this point in the symptomology and diagnosis we usually start throwing parts at the problem. Not necessarily the right way to do it, but it becomes (most of the time) more cost effective in the long run. Not really recommending it, just trying to explain the dead end in my ability to help you.

You have already replaced the battery several times. You have established alternator output. You have eliminated parasitic draw by diconnecting the battery at rest. There's not much left in the system but the voltage regulator.