DIY headlamp 18650 conversion with tp4056 charging module

Stuff needed:

• tp4056 charging module (USB TYPE-C)

• 18650 battery

• wire

• PVC heat shrink (43mm and 85mm) (I suppose slightly bigger sizes will be fine too.)

• Heatgun or hairdryer

• Rubber bands (to attach cell to holder)

• Clear tape

• Possibly a drill and a drill bit

• Soldering equipment

Disclaimer: I know you're not supposed to solder directly on cylindrical cells because of extreme heats involved in soldering. Before you do this, you should know how to safely solder on cells.

You can either use PVC heat shrink or some sort of tape to wrap things up. PVC shrink would be my recommendation because it's stronger.

The rubber bands on the "strap battery holder" holds the battery and also prevents the holder from sliding along the strap.

ASSEMBLY STEPS

Step 1:  Cut a 17mm long piece from the 85mm PVC heat shrink and a 68mm long piece from the 43mm one.

Step 2: Place tp4056 board in by sliding in the usb port first. Tape the "tp4056 holder" to battery so it's easier to work with.

Step 3: Wire up battery to B+ and B- terminals on the board. Solder long wires to OUT+ and OUT-. They should be long enough to reach the headlamp main body.

Step 4: Apply 85mm PVC heat shrink.

Step 5: Tape the long wires with clear tape. They should be routed to the top.

Step 6: Apply 43mm PVC heat shrink.

Step 7: Attach assembyl to headlamp strap with rubber bands.

Step 8: Attach/solder your OUT+ and OUT- wires to your headlamp appropriately. You may need to drill a hole for this on the headlamp. Luckily I had a hole on mine for the optional rechargeable battery's charging port. (Headlamp model is Solidline SH2)

Step 9: Attach "wire holder" on headlamp strap and hook the wires is.

And its done.