Replacing 4D Battery

[Ken13579]

I have spent a lot of time this winter trying to track down a deep-cycle, maintenance-free 4D battery to replace the original on my 309 (#22). I am trying to avoid paying $600 for an AGM, and also having to buy a Group 27 AGM for another $250 because you aren't supposed to mix types, and have had no luck at all. I replaced the 27 a couple of years ago with a Delco Voyager sealed lead-acid with a built-in hydrometer, which is a battery that I and other sailor friends have used on other boats with a lot of success. They don't make a 4D in the Voyager line. Since I am only off shore power when I am day-sailing or going on 8-10 hr. trips up the lake, and I have yet to anchor out in 5+ yrs with the boat, (no good anchorages in southern Lake MI) I am not sure why I need the 4D, but Catalina says I do. I have had several suggestions to just get 2 more 27s and connect them in parallel to replace the 4D. There is just enough room in the battery "compartment", and it would only cost about $200 total. (The Voyager 27 has an AH rating of 95 hrs.) Does anyone know of a reason that this wouldn't work or that I shouldn't do it?

 

[Maine Sail]

I have spent a lot of time this winter trying to track down a deep-cycle, maintenance-free 4D battery to replace the original on my 309 (#22). I am trying to avoid paying $600 for an AGM, and also having to buy a Group 27 AGM for another $250 because you aren't supposed to mix types, and have had no luck at all. I replaced the 27 a couple of years ago with a Delco Voyager sealed lead-acid with a built-in hydrometer, which is a battery that I and other sailor friends have used on other boats with a lot of success. They don't make a 4D in the Voyager line. Since I am only off shore power when I am day-sailing or going on 8-10 hr. trips up the lake, and I have yet to anchor out in 5+ yrs with the boat, (no good anchorages in southern Lake MI) I am not sure why I need the 4D, but Catalina says I do. I have had several suggestions to just get 2 more 27s and connect them in parallel to replace the 4D. There is just enough room in the battery "compartment", and it would only cost about $200 total. (The Voyager 27 has an AH rating of 95 hrs.) Does anyone know of a reason that this wouldn't work or that I shouldn't do it?

Firstly I know of perhaps one company that builds a "real" deep cycle 4D. The others, often labeled as Deep Cycle 4D's, are usually a dual purpose battery at best and not a true deep cycle type of plate construction. Most of these are used in the trucking industry so are designed to give lots of cranking amps and some reserve.

Secondly I would consider replacing your 4D's with 6V batts or a couple of group 27's or 31's if they'll fit. They will be significantly easier to get in and out of the boat and 2 6V batts will provide many more cycles than will a 4D and pack more amp hours into the mix in about the same foot print.

Catalina didn't really "tell you" you need to have a 4D that is just what they supply from the factory as the "token" stock battery. By using one battery they save money on making up "jumper cables" for banks in parallel and there costs are probably less using a 4D than multiple smaller batteries. Most Catalina owners I know swap them out for smaller case batts when they die.