Shimano di2 battery adapter for 27.2mm seat post

I swapped my di2 to another bike, so needed to transfer the battery to a new post. 3D printer to the rescue! (that's right, you can see I damaged the battery during removal from the previous post)

I designed this sleeve to fit over the di2 battery & fit inside a 27.2mm carbon seatpost.

Print this thing with flexible filament. You might need to experiment with wall thicknesses & infill percentages depending on your filament so that it's squishy enough to insert inside the post. I had to pr