18650 Battery Powered Lantern with Spiral Filament

This is a battery-powered lantern featuring a spiral “Edison bulb” filament.  It will fit any “wide mouth” canning jar.  It is powered by an 18650 lithium-ion battery.  Testing with my multimeter shows these lights draw about 115 mA when running at 3.0 volts.

No supports are required, at least on my Ender 5.  I printed at 0.2mm layer height and everything fit great.

A buck converter is required to step-down the voltage to 3.0 volts.  Space is provided for a USB-C battery charger.  Some soldering will be required.

The LEDs on the battery charger cause the glass jar to light up.  Red means it is charging, blue means it has finished charging.  The lantern may be used while it is charging.

I recommend using the Chunky Paracord Hook to hang this.

Parts Required

• 300mm LED Filament
• Battery Contacts
• Self-Locking Push Button (1208YD, WBK-1208)
• DC-DC Step-Down Buck Converter (LM2596S)
• Lithium Battery Charger and Protection Module (TP4056)
• M3xL4xOD5 threaded inserts (9 total)
• M3x6 screws (9 total)
• Multimeter

Assembly process

1. Using a multimeter set the buck converter to 3.0 volt output.
2. Add threaded inserts (9).
3. Solder two 3” black wires to the switch.
   • Connect one black wire to “OUT -“ on the battery charger.
   • Connect the other black wire to “IN -“ on the buck converter. 
4. Connect a 6 inch red wire to “OUT +” on the battery charger and “IN +” on the buck converter. 
5. Solder 6 inches of wire to two spring battery contacts.  One black, one red.
6. Add black battery contact in bottom of tube. 
7. Run red battery contact through top of tube. Leave about an inch at the top and let the battery contact dangle a bit.
8. Prepare LED filament. Add ~8” of wire on each end. The positive side has a notch.  I use the smallest solder seal wire connectors (white band), but directly soldering would work just fine.
9. Add LED filament to model with the solid yellow color side facing out. 
10. Screw the switch, battery charger, and buck converter into position. 
11. Connect black battery contact to “B -“ on the battery charger. 
12. Connect red battery contact to “B +” on the battery charger. 
13. Connect red LED filament wire to “OUT +” on the buck converter. 
14. Connect black LED filament wire to “OUT -“ on the buck converter.
15. Make sure bottom spring is in good position and add battery, negative side down. 
16. Align the top battery contact in the lid and screw the lid on. 
17. Carefully pass cover plate over light pole and screw in place. 
18. Screw onto jar.