I am with Geo on this one. I had a 12 trolling motor for a couple of years and had 2 deep cycle batteries up front. What I did was run one battery until it was low then switch the leads to the other battery for the rest of the day. I thought this was better just because I was constantly running one battery down and then the other back and forth so when I hooked up my dual bank on board charger both got charged independently to quicken the charge. I switched to a 24 v, variable speed 70lb thrust Minn Kota a couple of years ago and LOVE it. I still have the same dual on board charger that is hooked to both batteries independently and I have a jumper switch between the positives that I unhook at night when I charge just to let each bank charge each battery independently. Wish I had the 24v from the beginning and you will love the extra power when windy days. You can catch the 24 trolling motors at BPS from time to time at pretty good prices on sale. Plus with Xmas coming up, ask for BPS gift cards from everyone that ask and it will cost you even less. Good Luck.