Revised battery area.

Before 

After

 The original battery tray is pictured above.  Located below the quarter berth, it is pretty typical, a piece of plywood with some shallow barriers and two plastic battery boxes retained by nylon straps, brackets, and tiny wood screws.     As built, there was insufficient height for lids for the battery boxes, creating some risk with the exposed terminals. 

 

(Am I the only one that struggles with those straps?   Am I the only one that wonders about the 1/2" wood screws securing 65lb batteries?)

  When I chose to upgrade to LiFePo batteries I decided to revise and refine the battery area to reduce its footprint, create some space improve its security, and better guard the battery terminals.  

I also discovered another repair opportunity - a "floating bulkhead".   See that repair here.

First step was to make a fiberglass tray incorporating a hold-down strap.  To do this I made an appropriate-sized mdf form, slightly larger than the batteries themselves.  The form was covered with waxed paper, and a wet fiberglass layup draped in place to cure.  With this approach, the batteries can sit much lower than before, with a reduced overall footprint.

Multiple layers of cloth and CSM  trimmed on a cutting mat - a handy  tool from another discipline.

That glass was then laid up on waxed paper on a sheet of plate glass, then placed on the form to cure.

And removed from the form.  Lookin’ ugly!  

Trimming.

The aft end shaped to fit the hull curvature 

Stiffeners added to underside.   This part will be epoxied and glassed in place and integrated with the hull and bulkheads in this locker.

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Copper buss bars for parallel connection.  These are equivalent to "0" cable.  ("one ought") 

As I trial fitted the new battery tray, I was also considering the location of the new renogy solar controller, and how the wiring would be routed to it, the house, and start battery.  t  (I had previously run cabling and located a larger group 27 lead acid start battery in the cockpit locker as there was insufficient space for a group 27 and its box under the quarter berth.)

With this smaller platform, it became clear that the start battery would not only fit under the quarter berth, but that it could be positioned to help secure the house bank.  

Furthermore, I realized that the solar controller could also be located in that locker, and that this is also very close to the main battery selector, further consolidating all 12vdc infrastructure.  This significantly reduces the amount of cable involved, and eliminates the need for additional fuses.  Nice!

I now had to make a part to locate and secure the start battery, one that could be integrated into the house bank platform.    After pondering more complex approaches I decided to use the battery itself as a form, and to simply tape dual-layer corrugated cardboard to the battery to provide some clearance.  I covered that with waxed paper as before, and draped a thick dense layup over top.  Done.   

This bracket will be trimmed and fitted into the locker, then tabbed into place .

The start battery bracket fitted, and in the process of being glassed in place.  The screws serve only to secure the piece while the epoxy cures,  these are to be removed and the edges of the parts ground as close to flush as practical prior to tabbing the entire assembly in place.  

 ugly!  ...  tabbing-in halfway done.  I used polyester resin, cloth and CSM for the parts, but epoxy and biaxial stitch mat to fasten the parts in place.   Very strong stuff.

After some trimming and sanding

The roughing in is done, nearing completion with the solar controller installed.