[Richard]

Richard, Right now I have the alternator cable mounted on the chassis post of the isolator. So you say it can be left this way and will only charge the house batteries if I merge them.you mentioned monitoring the volt and ameter.What would I be looking for on those or watching for?

That is good. I would look for any sustained charging over a 100 amps. In my experience with 390, the belts would give up the ghost when the alternator pulled over a 100 for more than half an hour or so. 

And yes, you will only charge the house batteries when you activate the merge switch.