I made this to make my commute to work easier since I like to charge my battery at work. I used an ikea night stand leg to connect the two parts together (1.73"x1.43"x13.17"), but I've included the step file and a link to the onshape file that made the part if you need to modify the support to fit whatever you have at home.
The bolts going through the nightstand leg are 2.5" long and 5/16" diameter socket head bolts with nuts inserted into the hex holes.
The D Rings are mounted using .5" long .25" diameter pan head socket screws (so they won't snag on anything). The D-Ring I used had holes 1.74" apart, but you should be able to modify that distance in a step file or the onshape file if you need.
Fine or coarse threads should be work, but I used coarse threads.
You'll also want a strap of some kind. I just had an extra tool box strap that I was able to attach, but anything would work.
I printed mine with 5% infill except with 100% infill modifiers at each bolt location. The attached 3mf files have the bodies already added. I believe it should be able to open with all the modifiers enabled if you open it using PrusaSlicer. If you don't use the modifiers, try printing it at 20% or so but ymmv.
The author marked this model as their own original creation.