Very complicated this whole battery selection and charging. My summary of what I understand.
1 ) Trojan 6 volt wet cell batteries are the best choice for long distance Cruising Sailboat. And they can be replaced around the World ( at higher prices )
2 ) AGM'S are not the best selection for the World Cruiser and they have a Critical charging procedure to be followed. ( LIFELINE HAS AN EXCELLENT REPUTATION )
3 ) I am very close to buying
five ( 5 ) Oddsey PC - 1800 FT ( AGM'S ) for my house bank battery. And yes I have learned that one bank is better than 2.
I am buying
Odysset mainly because they will fit in my space ( outside the engine room ) Gulfstar
Have emailed Odyssey requesting direct feed back for the Battery Charger
that I need to buy and their detailed charging procedure that I would follow.
If I do not receive a clear reply from Odyssey, then I will not buy their battery.
Rolls 6 volt wet cell Batteries, I understood were the very best for deep cycle, but apparently from what I have read have serious Quality Control problems, and are very expensive.
All my reading on the various sites has me convinced that no battery will last more than 3 years on a sailboat. ( nearly always blamed on improper charging )
The SEARS DIEHARD MARINE
BATTERY ( 100 AH ) COMES WITH AN UNCONDITIONAL 3 YEAR WARRANT, AND IS MADE BT ODDSEY and sells for $259. Unfortunately the 100 AH RATING means I would need 8 to 10 of these and I do not have the space.
Otherwise these are the batteries I would buy.
In conclusion seems to me the best battery to buy and best suited for World cruising would be the 6v wet cell Trojan ( T-105 ) RELIABLE AND AVAILABLE ALL OVER.
Please correct me if what I SUMIZE IS NOT LOGICAL.