Ay Up Lights 18650 Battery Case

My Ay Up Epic / Half Epic batteries finally died after all those years. The lights are still excellent, but Ay Up doesn't ship new batteries to my country. So I decided to build my own by reusing the PCB, cable and rubber button from the Epics. 

WARNING: By following the below instructions, you will be working with LiIo batteries. Treat them wrong and they may cause a very serious fire. Stop reading here if you're not 100% sure what you are doing!

1. Carefully break the Epic/half Epic case open. They are glued together. Be careful not to puncture the pouch-type LiPo batteries inside!

2. Remove PCB, yellow rubber button and cable from old Epic. Properly discard the LiPo pouches.

3. Spot-weld two 18650 cells in series - you'll need a 2S (=7.4V) pack

4. Solder the PCB to the 2S pack

5. Put all in the printed 3D model and glue shells together with Epoxy, making sure that you get a proper seal to make the new case water-tight. Preferably use hot-glue for the cable port and don't get epoxy on the rubber button so that several years later they can be salvaged again :)
 

Final note, I was too lazy to put a lip at the perimeter of the shell where the top half meets the bottom. A lip would probably make it more robust, but the case nicely fits into the Ay Up neoprene pouch – even into the half-epic one if one gets a bit creative with scissors. Let me know if you happen to remix it with a lip; thx! :)