I’ve done this. I posted details a year or two ago. Don’t have time to describe the whole process….but a few key points….digging out the lead plates from the bottom is almost impossible, I tried. Finally I grabbed my saws all and cut off the top, about an inch below the top. Worked great. Then gutted the case, already had an opening at the bottom, connected cables a bit long. Surfaced the case cut edges on a belt sander and siliconed the top back on. Made a 1/4 inch plywood bottom, painted black, with locating pins. The battery hold down serves to keep it together. Take the hold down off, and you can lift the cover off the odyssey.