Did you use the MPP 1012LV AIO - 12vDC 1000watt output?
I have the same DeWalt Case, looks like a good fit for the components - if you have the hand-truck that goes with those cases, it would be easy to move this rig around.
Been trying to figure a way to build a system that would run a skillsaw in this same box, been tough to solve that puzzle, darn saws pull too many amps to start up. LOL. The MPP2724 AIO with a 304Ah pack will start and run my worm-drive Bosch circular saw (ironically since this is a big saw, but the worm drive seems to be lower in-rush current). The 2724 flashes a 07 fault code for a second but doesn't trip, and the code literally lasts one second and then disappears after the saw speeds up. But the 2724 will not fit that case so I built my set up on a garden wagon instead, not waterproof and pretty like yours though.