I'm thinking about a leftover 9.9 Yamaha. A little bigger than I need but the price is right. I think it will really push the boat at wide open throttle. So if I head in for lunch or move to a different location to fish using the kicker, it'll do some charging. The battery is a new group 29 deep cycle. Maybe I should have bought the 31 but I think I'll be in good shape even after buying new Cannon Magnum 5 downriggers which retrieve the balls at higher speeds.
Thanks to all for the responses.