I got tired of 2032 button cells dying when I'd forget to turn the sight off on my airsoft gun. figured there was enough vertical clearance to 3D print an enclosure for a protected, rechargeable, 123A battery to install on the pic rail in front of my sight and this is the result.

you will need:

• battery spring terminal approx. 10mmx10mm
• CA glue
• soldering iron
• 20AWG silicone insulated wire or similar diameter
• M3 bolt (25 to 30mm) and nut
• shrink tube insulation

Any print material should work but consider it may be struck by BBs, so PLA may shatter. use of extra walls recommended.

For the battery connections, connect the positive wire to the spring terminal in the rear of the enclosure, this allows a loose frayed wire to easily make contact with the larger negative terminal at the front(open) end of the battery housing. each wire is fed through their respective holes separately. for the solder joint to the positive terminal, feed extra wire through so you can reach the solder joint from the front, put a drop of CA glue at the rear of the housing then pull the wire back through seating the terminal flat into the glue leaving it to dry.

Most of these cheap red dots like you see in my pictures use a CR2032 battery, so the provided cap should work. Unfortunately I actually designed this over a year ago on a whim and did not save the CAD file for the final version of each part, never expected it to work so well and figured this red dot wouldn't last long. I'm sure you can design a similar file if needed.