Should batteries be disconnected when on shore power?

When I first got my 6-volt T105's I watched them closely while connected to shore power. I found they overcharged even with my 3-stage converter. So I installed a disconnect switch and now when I plan on being on shore power for more than a couple days, I disconnect them. Everything still works just fine. And that is how my system works. Every system works a little bit different and to monitor your battery situation is always a good start.