We have about 4" of ice on our nearby lakes. Winter is here but oddly enough, no snow to speak of. The ice is too thin and the weather too warm to ice fish.
I use a battery tender. As @airshot explained, these maintainers work exceptionally well. I use them on motorcycle batteries for 10 or more years and have never experienced any difficulties.
I love that area. I've done a lot of motorcycling in that area.
I must try dropping a line in that lake. Now I'm thinking of a summer fish out at Lac La Hache. Thanks for the idea.
If you mount the transducer on the opposite side of the boat from the first one, I can't see why it wouldn't work. Try it and let us know. That's actually a good idea.