I'm not a serious tourney fisherman by no means and I can't get out on the water everyday but I wished I could. I have a limited space xpress 16'. I went back and forth on what setup I wanted to do. I have a 24v ulterra ipilot and in the end I went with a single 24v 100 amp hr battery. It has its pros and cons about the setup. On the pros side of thing is… one battery to try and store somewhere, less wiring to deal with or run, PLENTY OF JUICE AND RUNTIME.
Cons…it's a dedicated battery being a 24v so I can only use it for my Ulterra, it has to have a dedicated charger of its own since it 24v, and if it dies (which I hope is no time soon) then I'm just SOL until I can get it replaced cause with at least 12v batteries they are easier to come by or pair with another to get you by for the day or so. I've never ran it all the way down even in the heavy currents below the dam but then again I'm not in a heavy boat and the spotlock adjusts power to keep me where I need to be. Bite the bullet once and I don't think you'll regret it. These things charge INSANELY fast