Rich,
A search of this forum will give you lots of ideas.

The change of batteries from 4D to 6 volt is a popular upgrade right now. For me the main reason I went with (4) 6 volt batteries is the weight of the 4Ds. At 130 or so pounds each, I would never be able to move these things. 6 Volt batteries at about 60 pound each, I can do that!

So I completed the upgrade last season and I am pleased with the results.

Search the forum and let us know if you still have any questions.

I agree. I made the switch on my 1999 model and it was very easy. 6 volt batteries are superior to 4Ds in almost every way. Ease in movement, capacity, life span and they will require little modification of the compartment in your boat.

Previous discussions with photos should still be here on line.

We are doing 4-6 volts and a small AGM battery for starting, I am picking them up today and starting to install and wire them Monday. I intend to shoot pics of the install and wiring. It is tight getting the 6 volts in were the 4Ds are but they will fit (US2200 batteries) and you get a lot more amps than you can from 4Ds. I could not find anyone up here who handled true deep cycle 4Ds other than Rolls/Surrette and I wasn't going to pay Surrette's prices, no matter how good they are. I would not consider this anything but a DIY job, I am sure a yard would charge an eye-watering price to do this work. It's time consuming but not overly difficult to do. It helps that I've done this twice before though.....

You might be interested in this: [url]http://www.c34.org/wiki/index.php?title=Catalina_34_Electrical_System_Up...

Well after near catastrophy due to weak batteries I replaced mine today with a new set of U2200 six volt batteries. It was a bit more of a task than I had hoped for. The bulk of the work was involved in cutting out the old battery box with a hand held key hole saw, great excersize and it releaved me of some obviously excess blood and sweat. I should also mention that loading 240LBS/$550 dollars worth of batteries into a dock cart and taking it down the gangway at low tide in flip flops is not one of my better thought out plans.

After removing the old battery box, I bonded two sealed 2X6x11" peices of PT to the old platform. I then screwed 3/8 sealed plywood to them. I had noted the most folks cut out a section of the seat base to allow the install of the batteries. I saw the heft of the structure there and could not bring myself to remove that much material. I instead rotated the last battery installed so it would fit without cutting any more material. This causes that battery to sit up about half an inch taller on shims than the other three and the terminals just clear the plywood cover for the seat. I did need to use nuts on the studs as the wing nuts would not fit in several locations.

This was a full day project, I hope it solves my problem but, it buzing out the wiring I noted a high resistance on the primary ground circuit back to the positive terminal, I need to investigate that further next trip up. I have been suspicious of the battery select switch. Regardless I will appreciate the added amps to the house bank.

Steve,
I think I read somewhere that wing nuts should not be used on marine battery terminals, even though they are often supplied with the batteries. Something to to with vibrations and the wing nuts coming loose. Aircraft nuts (the kind of hex nut with a plastic insert) should be used, as they will not back off with vibration.

Glad to hear that your install went well.

PS-The mental image of you in your flip-slops with a heavy dock cart on a steep ramp is a great one!!