The year is 2015, not 1985. They make these smart chargers to be installed in the boat, hooked up, plug it in and forget about it. Last thing I want to do after a long day on the water is lay on a wet back deck, flash light in one hand and eight clips in the other to hook up to three troll motor batteries and a cranking battery. In the 70s it was the only option. In 2015 you dont have enough money to make me do it.