Ah batteries – we can’t live with them and we can’t live without them. The 12 volt lifestyle can be can be quite liberating. After all, you have all of this modern stuff with you and you are running it off of a battery. Or you are using this magic box to convert 12dc volts to 110ac – then running other things like DVD and TV and computer. The batteries, however, need careful attention to mounting, since you don’t want 500 pounds of lead flying around when things get rough.
Malo sent the boat with what they claimed to be about 280 amp hours. That might have been the factory rating, but in actually usage it was under 250. This might give you a usable range of about 100 amps. These euro batteries were quite lite for their rating, and they sucked dry very quickly. One day at anchor in the Northwest, running the heater, would suck them dry. I knew this was an issue when ordering the boat, and had intended to upgrade the batteries all along, so this was my first major project on the boat.
The factory battery box was a beautiful fiberglass box mounted under the forward settee next to the mast. It had all of the electrical fuses on it. First step was to disconnect this wiring, carefully marking all of the lines and circuits. Getting the batteries out was easy, they did not weight much more than 80 pounds each.
Next, I constructed a new box out of plywood and fiberglass, built into the boat. I glassed in a 3/4 panel for the bottom, and 1/2 inch for the sides. This was all taped into the hull and waterproofed. The box was designed to hold 3 4D gel batteries. They weighed in at 470 pounds, and would give me 525 total amp hours. Hard to believe, but this was just barely enough to power the cruising lifestyle.
When installed, the batteries caused the boat to slightly list to port. This was balanced out by moving 5 cases of beer and wine into the starboard lazerette.
The batteries are held down by nylon webbing on stainless ratchets. They are mounted to padeyes that go through the bulkhead, and underneath the deck. It took me a while to engineer this hold down system, but they are now completely secured. All of the cables were remounted on the side of the box after it was painted with gelcoat.
Malo had installed a great little ventilator hose for acid batteries. I left this in place, even though it is not needed for gel, because these batteries will die in some out of the way place where I can only get lead/acid batteries.
How do I know this – simple – just plan for the worst, and maybe things will be better…..
This was a big, stinky job. There is just barely enough space to get these batteries in. To date it has worked out OK. I still need to get the labels on all of the cables, but now I have messed with the boat so much, I know which ones are which. 
The completed box. The black bands are the nylon straps. There is one set that go around the front of the batteries to hold them snug against the bulkhead.
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