Relocating batteries, again
The house battery bank was placed in the starboard side locker in the aft cabin a few seasons ago, but since that several new aspects were discovered, which made me reconsider our choice.
1. I am thinking about replacing the wheel-drive autopilot with a below-deck type, for which the best place would be the aft cabin locker, which is currently occupied by the batteries.
2. In the future I might want to get an electric windlass, which would either require a separate battery closer to the anchor locker or long, very thick (and expensive) cables to minimize voltage drop.
3. The weight distribution is not optimal with most heavy stuff (diesel tank, waste tank, batteries) located on the starboard side.
Earlier I considered the locker in the saloon which close to the centerline of the boat, but that's one of the best lockers for storing food (easy access, close to the galley) and we didn't want to give up on that. I took some more careful measurements and realized that it's possible to fit the three 100Ah batteries in the long port side locker under the saloon settee. It's tight, but it would fit. So I decided to give it a try.
I made a new shelf out of plywood to level out the curvature of the hull and and redid the cable work. The length of the cables remained almost the same, no big change there. I used 50mm2. The isolation switch and a new fuse got installed in the other locker with easier access. The cables were led through already existing holes, so no new holes had to be drilled.
The shelf got painted with Yacht Primer and Toplac in gelcoat white in several layers and screwed down to the inner-liner of the hull with 10 stainless steel screws. The batteries are held in place by straps and wooden separator pieces. There is an air gap between the backplate of the heating element and the batteries.
Now the house bank is in a better location regarding weight distribution and closer to the anchor locker in case we decide to install an electric anchor windlass. I plan to split aft locker in two parts with a plywood wall later on, to have a place for the autopilot and a storage area.