Originally Posted by mikekomm
I just bought a 42' boat that will need some of the batteries replaced. At least one of the Group 8 batteries and 3-4 of the Group 12. I want to purchase high quality "real" deep cycle marine batteries. Any suggestions on where to purchase the batteries, cables and terminals?
Group 8 is that 8D? I prefer Interstate Batteries and have had excellent battery service with them and they're marketed at a reasonable priced.
Depends on your needs, as we've discussed here many times, not all boats and boating styles are the same. I have a generator and only use my battery banks for household and engine starting. the generator for everything else. I use 4D flooded lead acid batteries and they last well over 7 years; usually 10 year with minimal care and maintenance. If you use an inverter to create AC power from 12 volt DC and live off your battery banks, then your needs will be different and battery life will likely be less.
Before you replace your batteries, you need to know how you will use the boat. Do you have a generator, is the boat all AC electric, Cooking, heating. Lots of "need to knows" information there.
A Couple of observations:
You can use deep cycle batteries for household and electronics. But engine starting batteries should not be deep cycle. You need the high output of starting batteries for this purpose.
When you replace batteries, not a good idea to mix new batteries and old batteries in the same bank. Keep old with old and new with new for best performance and battery life.