Re: Battery Sizing - am I crazy?
I survived with no problem with two Group 27 deep cycles on my previous 30 footer with a 2-cylinder Universal diesel. Even on 2+ week cruises. Current boat has two Group 31 deep cycles and also fine with similar usage. They start my Yanmar 3GM with no problem. You could go with one starting and one deep cycle, but I would just go with two the same to keep things simple.