Here's the finished product. After a little over two years of what seemed like an endless list of design tasks and fabrication details, I finally ran out of work and it all came together! Even though I'm using AGM (Absorbed Glass Mat) sealed batteries, I wanted to be able to easily access them for inspection so I made the truck bed hinge at the rear and added two gas springs to assist in raising the bed and hold it in the upright position. This took a lot of head scratching to get the hinge positioned correctly so the tailgate wouldn't crunch into the rear bumper. Sizing the gas spings was a challenge also. I ended up with a 150lb spring on each side.