Over the years I have taken out my TT batteries and hooked them to a trickle charger in my garage during each winter. I now have the TT under covered storage at a local storage yard which has electric...
My WFCO wasn't awesome by any means, but aside from no real boost mode, it charged and maintained the batteries OK.
I used to mess with removing the batteries, but that is a pain, literally. Mine sit on the tongue of the trailer that's plugged into shore power. I haven't noticed that huge electric bill noted above.