Does the main battery disconnect need to be in the on position for the batteries to receive a charge while I'm connected to shore power?
I am pretty sure that the battery disconnect switch can be either on or off and the batteries will still be charged when you are plugged in. Plug in and look at the voltage. It should be well above 12.7 when charging. Mine is typically around 14.2 when plugged in. So, if you see the increased voltage, you are charging the "house" batteries.
Tim
Prior to 2098, I think, the switch had to be on to charge, after that, either position will charge.
i have a 2016 - the monitor does not show anything unless you turn the 12V switch on. I have a Victron shunt with bluetooth that reports the voltage, it does not matter what setting it is to report back if there is any charge or discharge.