How to charge the MediaTek LinkIt ONE battery

To charge the battery, change the power switch on the board from USB to battery, plug in the battery, and plug the board into either a computer or a USB phone charger. 

Check the battery level

1. To check the battery level, plug the board into your computer and set the program mode to UART.
2. In Arduino, set the board type to LinkIt ONE (Tools > Board >LinkIt ONE).
3. Then go to File > Examples > LBattery > Battery. A new sketch will pop up with the battery example code in it.
4. Compile (check mark in the top left), then run (arrow icon next to compile).
5. After it finishes uploading, click the Serial monitor icon (top right).
6. The serial monitor will print what percent charged your board is every second.

Check out this article to see how LinkIt ONE battery performs:

https://www.hackster.io/AgustinP/linkit-one-wifi-battery-test-729ccb

Happy coding...