In order to add electrical circuits to an armored vehicle at work, I added two 15A DC breakers.

If the bed leveling is set properly, there will be almost no "elephant foot", and the breakers will fit perfectly.

The hardware to mount the breakers are two 8-32 screws per breaker. To mount the panel, I used 6-32 hardware around the perimeter of the plate.

I've included the Fusion 360 file if someone wants to make a much larger breaker panel for their RV or boat.