Would this thing work for this scenario or are these things toast?

I have two deep cycle RV batteries for my travel trailer. Summer time camping I go to RV parks and plug the trailer in, so the batteries aren't used but they are wired into the trailer. The batteries are removed from the trailer when not in use.

When hunting season comes along I use my generator to charge the batteries and run the power when the generator is off. The batteries are about 2 or 3 years old and no longer hold a charge for very long.

The batteries spend more time out of the trailer than in it.

Any ideas if this battery minder would bring them back to life so they hold a charge?

Pete

______________________________________
64 Fairlane under construction, 420W, C4, ladder bars, etc
92 Mustang LX Coupe 4cyl power