My first project spent more than 12 hours on it was made for converting old double suspension mtb into ebike and wasnt able to find any battery case for it online under 60 euros and that size

hole on the batery case is for big xt60 connector from China (fotos attached)

can fit 39 batteries (13s3p) without spacers between batteries/or 26(13s2p)with spacers 

recomended filament with tensile strenght at least as PETG CF 

has place for m5 bolts , washers obligatory for shock resistance (aslo recomend placing rubber between frame and holder

print settings for CF PETG 

1. layer hight ≤0,16mm if you can go lower go lower (only in case of cf filaments)

2. wall count 6-8 for case(walls have to be completely filled) /  8walls for holder

3. 40-45%infill Gyroid

4. no brim

5. use suports only for case

DO NOT USE PLA it melts on sun ,

recomended to seal everything for water protection