Should batteries be disconnected when on shore power?

Well, close. But the wizard jumps the voltage back and forth between bulk and float quite often.

And to clarify, the PD 9100 series w/o the charge wizard plugged in, is a fixed voltage converter 13.6-8 volts.

The PD 9200 series, is a 3 stage converter because the charge wizard is built in. The only thing that can be plugged into the 9200, is the pendant, which does nothing more than give you manual control over the charging stages.