6 Volt Batteries in a Catalina 36 mkII?

[Greg Miles]

Has anyone replaced their (2) 12 volt 4D batteries with (4) 6 volt golf cart batteries (in series by pair)? I have heard that it increases available amp hours. Do they fit in the same location on a 36mkII?

 

[Trevor]

Yes

There should be some info in the archives, but I upgraded my DC system to include six 6 volt batteries for house and a single Grp 27 battery for engine start on my Mk1 C36. I have 3 batts in the aft game table, 1 in the forward game table and 2 under the aft bunk. The start battery is now under the sink in the main salon. All charging (shorepower and alternator) goes to the house bank and an Echocharge trickles charge from that bank to the starting bank. I monitor the capacity of the house bank with a Link 10 meter. So far it works great...Best of luck,TrevorC36 #640

 

[Gene Foraker]

6 volt batteries - Almost perfect fit

My 1999 C36 Mk II burned out one of the original 4D's with a bad cell last summer. I replaced it with 2, 6 volt golf cart batts from Sam's Club. They fit fairly well next to the other old 4D, but are a little higher and longer. They no longer fit in the battery box and the wooden cross beam holding them down had to be left off. They are wedged in pretty well under the aft seat, so they should be safe for anything short of a knockdown past 90 degrees. I intend to strap them down this year. The advantages are mainly price and being half the size, easier to move on and off the boat. I think the total amp hrs is only a little higher than 4D's but they are rated for many more cycles and should last longer. They were cheap enough to experiment with, and I can always go back to a 4D in the future.