This post has been online for a while, but I thought it was worth adding some new info, rather than start a new post.
When I arrived at my boat this past October to prepare her for cruising, I found that 5 years on the hard can be on a boat. Sometime within the past year, the sensor wire for my solar panel charge controller corroded off and all seven batteries were fried. As such, this thread gained a whole new meaning for me. I previously had two 6v deep-cycle batteries on the Port side beneath the fuel tank, and two more of the same behind the engine. There were two 12v dual purpose batteries in the Stbd position, and one more backup 12v start battery under the steps. All were flooded batteries, although the two in the Starboard area were maintenance-free.
During the past 3 month during my refit (still under way) I was fortunate enough to have 10 batteries donated to me. Six were small AGM batteries that fit nicely under the forward dinette bench (where there used to be a drawer). This gets them out of the heat of the engine compartment and also gets the weight lower and more centered. The other four batteries are 6v Deka deep-cycles. Two of these will be placed under the Port fuel tank as before. But the other two will be returned back to the normal Port battery position behind the galley bulkhead and cabinet. Yes... this is a horrible place for monitoring and maintenance. But I think I've come up with a good solution.
While I was in the process of rewiring the boat, I ripped out the back of the galley cabinet to replace it with a new panel that was void of holes from previous installations of various things. When I rebuilt the cabinet, I cut two holes in the bottom that would allow easy access the batteries for checking and maintaining water levels. It now has a false bottom that inserts into place. All I need do is temporarily remove items from the cabinet, then open the inspection ports and service as needed. While this space is a general pain for access to batteries, it's pretty much wasted space for anything else. It's kinda' a shame not to use it for batteries. Of course, I will still need to come up with an effective way to ventilate and cool the engine room to enhance the life of the batteries.
The access openings are cut at about a 20 degree angle that corresponds to the angle of the battery shelf beneath. I'll post some photos as soon as the project is completed. Or, if this turns out not to be as good a solution as I expect, I'll update the post as such.
Jack
