There is no one answer, as there is no one boat or variety (or paucity) of charging sources.
AGMs are expensive and (to my mind) a little oversold in terms of lifetime. On the other hand, if you are trickle-charging them (at the voltage they prefer) on a boat on a mooring
, or if the flatness of your bilges means they can lie on their sides happily, they are a great choice.
The newer carbon foam batteries need to go through a cycle of ownership
before we can judge.
The Li-Ons are great (particularly for a race
boat) but are they rugged enough to go to sea? Are they worth the higher cost per Ah over time? Dunno. I do know I had a Li-On battery in a laptop
burn on me once. A full-sized marine
battery would be a nightmare shading into "abandon ship". Both carbon foam and Li-On are going to be hard to replace in distant lands. I mean, there's cruising the ICW
and the Caribbean
, and cruising New Guinea or Micronesia. Very different scenarios.
I have six L-16s, a fairly heavy (120 pounds, but I can manage it) 6 VDC FLA battery. They are series-parallel wired to make one considerable 1,575 Ah house bank. I've got a full keel steel cutter
, so keeping 800 pounds of batteries right beneath the mast
actually stiffens the boat a bit. I have multiple charging sources but I wanted to extend their life by sticking to the 75%-100% range, which in theory gives me 3,000 discharge cycles if I'm clean and do my care and feeding. So my energy budget
is actually only 25% of 1,575 Ah...I'll have to run a tight ship if it's cloudy, I'm not motoring, it's calm and the two Honda
2000s are busted. You can see where I'm going with this. Asking about battery types for cruising is so utterly contigent on so many factors (style of cruising, type of boat, access, where you are going, how do you charge them, how many loads you run, etc.) that there's no one answer. Just best answers for you.