Even with the "smart" converter/charger in my Roadtrek I would not leave it plugged in all of the time on the driveway. There is no need to pay for that continuous power draw. When we are not traveling, I check the battery power level parked on the driveway every two weeks or so. If the batteries are down, I plug the RT in for 12 hours and this keeps the batteries up. We have a generator that needs "exercise" once a month and that charges the batteries in my RT as well. Older Roadtreks have different converter/charger set ups but following this idea should work for all.
There are numerous things in your B that trickle draw power from your battery such as the alarms. You can control that if you have a battery disconnect switch to turn everything off. Keep in mind though you have to turn it back on if you want to charge with engine running, shore power or generator.
Examples:This is the battery disconnect switch in my former 2005 Pleasure-way Plateau with an added Progressive Dynamics Charge Wizard that I installed. It was located inside a small cabinet under one of the sofa ottoman seats.
This is the battery disconnect switch on my 2011 Great West Van Legend located under the kitchen cabinet at the sliding door entry.
2011 Great West Van Legend Sprinter B Camper Van
Visited states in an RV