A 2x1x3 Gridfinity bin that can hold 4 Sony NP-FW50 batteries built on top of kennetek's Gridfinity Rebuilt in OpenSCAD.
My code for this is also open-source. See it on Github.
The author remixed this model.
I used the original Gridfinity Rebuilt model for the body of the bin but used my own code to cut out slots for the batteries.