Walmart sells at Atwood Marine battery tender. Its a permanent mount system. Very small and easy to use. I use it on my boat all the time which has 2 deep cycle marine batteries wired in. One for the electrical components on the boat and the other for the stereo. Always keeps them fully charged and very easy to conceal and use.
Horsepower is how fast you hit a wall. Torque is how far you move a wall.