How to Charge a Lithium Ion Battery Without a Charger

By Stephen Benham

Lithium-ion batteries require a constant charge rate and should not be fast-charged. If you have lost your Lithium-ion charger, or it doesn't work, don't try and adapt other chargers: the result could be dangerous as the charge rate could be above the tolerance of your battery. The best way to charge a lithium-ion battery without a charger is by connecting the device your battery powers to a USB cable, connected to your computer. USB cables contain several data and ground wires, but also have a built in charge wire and the output is suitable for charging a lithium-ion battery: the USB charging wire supplies 5 volts from your computer with a milliamp current of 100mA to 500mA.

Things You'll Need

  • Computer
  • USB cable
  • Device with USB socket
  • Lithium-ion battery

Step 1

Check the device your lithium-ion battery powers. Most devices have a USB sockets.

Step 2

Insert one end of a USB cable into your device's USB socket. Ensure the lithium-ion battery is inserted in your device.

Step 3

Insert the opposite end of your USB cable in your computer's USB outlet socket. Turn on your computer and your lithium-ion battery will start to charge while in your device. Your device will indicate when the battery is charged.

Tips & Warnings

  • If your device does not have a USB socket, you can purchase a piece of hardware called a lithium-ion evaluation kit from your electrical or computer store. The evaluation kit connects to your computer via a USB and then connects to your lithium-ion battery so you can charge your battery without a charger.