Apologies, I should have said it’s a ‘mountain’ type bike with a threadless 1 & 1/8th inch A-head type headset. I think the problem part is called a conical centering/compression ring (4th down on the attached picture)
I’m currently using one battery at the time with a bodge job connector. They’re the 4ah version.
I’ve designed and drafted a new connector for 3D printing. So when I get that done I’ll run 2 or 3 in parallel.
They were going into an ebike rear rack which held the old battery but that steadily has disintegrated. It would be nice to attach them to the frame in some way. I’ve got a few ideas.
On recommendation, I’ve bought a reel of black PETG for the job which I’m aware will require special procedures to use in the SLMS machine.