At the dock at home and the boat plugged in on my 3500 , is it good practice to leave the house battery switch on to charge the house battery's??? Or do they get charged with the breaker on for the battery charger and the house battery switch off ??
I leave it off. The chargers will charge the batteries without the battery select switches being in the on position. I prefer not to have anything non-essential energized when I'm not on the boat. The bilge pumps and the chargers bypass the battery select switches (at least on my '03 35 Open).
On an unrelated note, I also close all the seacocks and have a sign that I put on the helm to remind me when I power up the boat.
I think you'll find a mix of answers. If it's during the year when I'm using it a lot I prefer to leave the 12v power on so the stereo memory doesn't reset in case the 110v power goes out so the stuff in my fridge won't go bad. If it's going to be an extended enough period of time though I'll empty everything out and shut off the switch.