I use two blue top Optimas hooked in parallel (troll fury) for my trolling motor and one blue top for the cranking and depth finder. My boat is pretty light (1654 aluminum F&F) and I can troll three days straight in heavy wind without recharging....they are amazing. I started to buy a Minn Kota on board charger but was told they were not recommended for the AGM batteries. I got a charger from Cabella's that has a setting for those which works great. I leave it plugged in all the time as recommended. Before I got the Optimas I used the WM brand but they didn't seem to hold as good a charge. If you get the Optimas be SURE to get the blue tops which are deep cycle. I would not recommend a cranking battery even for the outboard if you are going to also use it to power electronics.