Originally Posted by Nightwatch
Fairly sure they wont fit. I checked into this with my 2008 23D, and unless you have a slightly larger box it wont work. Might be easier to go with 6 volts as you just have to raise the height of the box. Width can be limited by the frame width.
NIGHTWATCH has the right idea. You gain amp hours with 6 Volts which is what you want and the "fix" is simple by increasing the height of the box with four pieces of pt wood and reattaching the lid. I ripped some 2" x 2" pcs and screwd them to the top of the box.
Look at this link for dimensions: BCI Battery Group Size Chart
It will give yu battery dimensions for various "Groups" assuming you remember how well you Group 24's fit the box.