I only had four CR2450 rechargeable batteries and I liked the original design as the batteries do not touch each other. I am new to Fusion and all of this modeling stuff so I learned how to cut the STL into thirds and smooshed them together. 

I tested each spot with a cell and also in one of my drawers, as seen in the photo.

I printed the one in the photo with a 0.6mm nozzle, Elegoo Gray PLA, with a 0.4mm layers.

Please be kind :)