2 Quotes from an article I read last week.
Dock Talk & Battery Life Gossip:
"Owner to owner, dock talk, or dock gossip is essentially as
useless as boobs on a bull and not meaningful. It could only be meaningful if you have a baseline for comparison & consistency and everyone used their batteries identically, and we simply don’t. Bottom line, ignore dock talk on battery life and learn how to test your own batteries for their true deliverable Ah capacity."
"Don’t laugh, if I had a dime for every boat I have seen using
starting batteries as deep cycle banks I would be much further ahead towards retirement."
What’s the difference?
"Starting batteries should not be used for deep cycling, but deep cycle batteries can easily be used for most starting purposes. I use deep cycle batteries for starting on almost all sailboat installations. Why? They last longer and can be called upon for cycling if or when the house bank fails. A small aux diesel engine can be started by even a PWC battery so a decent deep cycle house bank makes easy work of motor starting"
Light Cycle vs. Deeper Cycle NOTE: This article deals with FLOODED marine batteries, not AGM or GEL batteries. The Problem: The problem, as I see it, is one of dishonest marketing where multiple battery types wear the same clothes (sticker) and will perform differently when
marinehowto.com
This marinehowto.com is a great resource and has several detailed articles on batteries and many other topics.
I just found out that my batteries are actually opposite of what they should be, meaning the house battery is actually a cranking battery and my starting battery is a deep cycle battery. I had never had an issue so no reason to look to see how thing were wired. Bought the boat new in 2014 so these are or original. Only discovered this when my house battery died when boat was on the trailer for 3 weeks. When checking where the draw down came from I discovered that the house battery was tied to the Cranking Battery. (Both batteries are Interstate)
I've contacted the Factory and the dealer where I bought it to see how/why it's like this but no response from either yet. The Cranking Battery has it noted on the top of the battery with 1" letters so hard to believe someone made that mistake.