Now these will happily fit in the box, indeed they were chosen to do so. But because they are so short they will be a pig to get out, and I want to hide a fuse box and maybe some other wizardry in there. So, I have come up with this:
It's a simple carrier made from 18 swg cold rolled sheet; the batteries enter from one side and it is lifted out of the battery box by the two handles on top. The top deck is to carry the fuse box. I plan for the cables to exit through a slot in the upper inboard edge of the battery box:
So, now I have identified where the cables are going, I can cut a slot in the box. A coping saw and a half round file does the job nicely:
All that remains is to put the lid back on and look at sealing the lid.