I installed a ProMariner 3-bank (only using 2 at the moment) for the same reason. I can go out in the afternoon to get bait in the livewell then hook up power at the dock to keep the batteries at full capacity overnight while the baitwell runs. It also makes it nice when I get home. I just run a power cord out to the boat and plug in to keep the batteries trickle charged and regulated. I installed a receptacle under above the footrest/under the console on my 215, that is connected to the battery charger inside the console. That way I don't have to open the console, just plug in to the receptacle on the outside of the console. I'll be showing this setup in the DVD when it is released.
BTW we're shooting the final segment of the DVD Thursday and I hope to have it edited within a couple weeks after that. It will be ready by Christmas for sure.
