I'm installing a 6k Growatt, using 230 amp EVE cells. Last weekend I got all the AC wiring finished and this weekend started on the DC side. I wanted something compact and secure for the batteries, and found a metal toolbox on Amazon that fit the bill perfectly. It's tight and made for challenging build but I like how it's turning out. I lined the back of the box with adhesive backed neoprene to provide a little cushioning and insulation. The two ends have been fitted with a piece of a 1/2" thick plastic cutting board. This wasn't necessary but I had the material already and it served the purpose. The plywood bottom also was something I had laying around and turned out to be just the right size so I decided to put it in there.