Re: battery shut offs
If you got one of the battery isolation switches and followed the directions, your converter will probably not charge the batteries as most of such devices say to install it directly to the battery terminal, with all other connections to it. My suggestion is to always install such devices in the negative side between the negative battery post and the ground cable.
For the converter to charge the batteries when it is open, it would have to connect to the battery post directly. Most likely it does not. But there is no reason that you can't close that switch when you go to connect the power cord. I would close the switch before you connect power to prevent a big arc when you close it due to a surge of current. If you do that everything will work as in the past.