For a boat that sits for months at a time, the smartest battery charger I have ever had is "me".... To further clarify, my boat sits in the water at the back of my canal front home year around (except when I cruise of course). The only 12 VDC breaker I leave on is the vacuflush system which virtually never cycles. I have three 4D lead acid starting batteries and 4 Trojan golf cart batteries for a house bank. I have three bilge pumps with individual float switches all wired directly to different batteries. I have a Promariner battery charger, a Xantrex battery charger, a solar charge controller and a battery minder ... I can uses any of them individually or all simultaneously. When I am home and not cruising, I turn ALL chargers off for days at a time (like up to a week or ten days). My bilge pump cycle counter shows zero cycles of the bilge pumps. Every week to 10 days I turn on one of the chargers for only a few hours and all batteries go to float mode within 1 hour. BTW, I also check the boat every few days while at home and always listen for my loud bilge pump alarm.. Doing this, I am currently at about 6 years on my 4D batteries; house bank installed 5 years ago is going strong. Before I used to leave one of my smart charges running all the time; 4D batteries would die at 3.5 to 4 years. When I am away from my house and boat for extended periods of time (multiple weeks or months), I turn on one charger AND the solar charging system. If I lose shore power, I will still have solar charging in case my bilge pump needs it. Also good neighbors will hear my bilge alarm. Jim Gano