[C38] Battery box rebuild

[Les]

Hi, everyone,
	I am finally ready to do my rewiring project.  The first thing I want
to do is modify the battery box to accept 4 golf cart batteries.  I seem
to remember that someone said they had already done this, so I am
looking for pictures/process to help me avoid mistakes.

	I think from my measurements that the box needs to stretch about 2.5"
port to starboard, and I can rip out the 2" or so divider, and replace
it with about a 3/4" inch one in that new dimension.  This would move
the inboard battery about 3-3.5" beneath the current seat edge, so that
would probably have to change as well.  I think I could probably just
cut the new desired dimension out of the top, remove the large end of
the box and extend it 1.5".  However this may encounter some issues as
it approaches the truncated end of the settee by the galley cabinet.

	The center divider could be cut out, and fiberglass tape used to repair
the box bottom, with a new divider tabbed in place by the same method.
Probably 1/2" marine ply covered with a layer or two of cloth or tape.
The outboard end would be stretched 1-2" and re-attached with glass tape
as well.  This would give me a box that measured about 22.5" 
by 16" and the batteries are 10" by 7", so they would fit with some room
to spare.  Nylon straps across the battery tops would hold them in
place.

I plan to add bus bars as well to make the connections cleaner.  I no
longer have a batterycharger there because I have two 65Watt solar
panels to maintain the batteries.  This gives me a charge current at
just under 9A peak, and here in CA, this gives me about 50AH/day.  This
seems to be enough to let me run the refer with no impact.  At anchor I
would have to run the engine about 4 hours every 5th day to replenish
the house draw (we're relatively frugal on power).  We use about 4
lights during meal times (6A for 2 hours) and 2 lamps for reading (3A
for 3-4 hours).

Under sail, the autopilot draws about 1.2A, so it would deplete the
battery in about 50 hours with the instruments and refer running at the
same time, so about every other day for 4 hours when under sail and auto
pilot full time.

	My total instrumentation is a knotmeter, a depth sounder, GPS, VHF, and
Autopilot.  The knotmeter is very low drain, the depth sounder about
0.25A average, and the GPS is about 0.75A in daylight, a bit higher at
night.  The vhf draws about 0.25 in standby.  Thus my total draw is
about 2.25A continuous underway under sail, and add about 2A for running
lights at night (we are coastal sailors and don't do much night
sailing).

	My engine has a 35A alternator which seems adequate (the batteries
typically drop to bulk at about 12A after 20min run time.)

So how does this measure up to those with more experience?

Regards,
Les H