You can find battery boxes at the following websites.-
http://www.driveev.com/jeepev/convpgs/tbatteries.php
http://www.timnolan.com/etruck/BatteryBoxes/BatteryBoxes.htm
http://www.geocities.com/mathenybrian/mr2.htm
Building Racks for your Batteries
Once you have chosen the location of your batteries you can
build racks to hold them in place. Every assembly will be
different, so we can’t give you exact dimensions here, but we
can suggest materials.
We used about 30 feet of 2 inch angle iron as the base of our
frames, a great place to start.
In our recent truck conversion we mounted the batteries in
the frame on each side of the drive shaft. It worked well.
Angle iron is welded across the frame members in a way that
it holds the edges of the batteries exactly. A bottom plate of
steel or stainless steel works well too. We used old discarded
stainless steel chimney pipe that we obtained from the local
chimney man who regularly replaces chimneys. The old stuff
is tossed so we grab it for our projects.