Made a battery box for my R2D2 build, it works with the Mr Baddeley Printed droid v2 files. Its designed to use the 4 bolts that hold the center leg on, making the battery weight centered over the foot. note that i make my center leg support frame out of wood, cut to shape of the printed version for extra support. This mod makes it all solid and should center the weight better. It's sized for my Power Sonic Model PS-1270 F1 12v 7amp battery (https://tinyurl.com/stedtaj).