I store my boat outside and use it about 1-2 times a month in the summer. Before this trickle charger, I owned a battery jumper that cost about $200. It also worked, sort of. But isn't as nearly as convenient as this product. With the battery jumper, I would have to remember to charge it first and bring it with me. Which takes about 5-6 hours to fully charge one of those. So there were many times I would forget to charge it and ended up needing it and be out of luck because it didn't have enough juice. Anyways, what I like about this solar trickle charger is I just automatically hook it up after I cover my boat. And I don't have to worry about the battery being dead.