How to make a USB charger for Li-ion 18650 batteries

18650 series batteries are one of the most common and frequently used batteries. They are used in flashlights, radios, metal detectors, etc. Radio amateurs have not ignored them and also use them wherever possible. Often the device powered by this battery does not have a built-in charger and the battery must be removed. To charge it, you can use a purchased device or make your own from a piece of PVC pipe. This will be very useful, since usually purchased options are powered from a 220 V network, but this sample can be charged from any USB port.

Will need

• Li-ion charging module 3.7 V - http://alii.pub/5bec2y
  
• 2 LED different color - http://alii.pub/5lag4f
  
• 18650 battery holder - http://alii.pub/5m46x8
  
• USB connector - http://alii.pub/5m472v
• 18650 battery - http://alii.pub/5becfz
• PVC pipe 30 mm.
  

Manufacturing a charger for 18650 series batteries

We take the charging module and battery holder and place it on a PVC pipe. Add 5 mm on each side and determine how long the piece should be cut. Use a hacksaw to cut off a section of PVC pipe. We apply the holder and, with a margin of 5 mm on each side, cut out the window in the segment. We grind off all burrs with a file. We cut the cut-out plug to the size of the battery holder. Glue it to it with super glue. We take a USB connector from a non-working flash drive. Solder the power wires. In 3 mm plastic we mark 3 plugs and cut them out. In one, use a utility knife to make a cutout for a USB connector. Glue the connector with super glue. Solder the chip on the charging module LEDs and solder the usual ones. We bend the output as in the photo. In the upper part of the workpiece we make holes for LEDs. We glue the plug and holder down. We glue in the second plug, making cuts in it for the leads coming from the holder. Solder the module to the holder wires and the USB wires. We install the module with LEDs and fix it with glue. Glue in the last plug. USB charger for Li-ion 18650 batteries is ready! Install the battery into the holder. And we plug the charger itself into a charger with a USB socket from a cell phone. Lights up red Light-emitting diode, indicating that the battery is charging. Once the battery is fully charged, the green light will turn on. Light-emitting diode, and the red one will go out. Now you can take the charger with you and charge it from any USB port: even from a laptop, even from the radio port in the car.

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