When the battery level is less than 20%, the ESC Key will start blinking in red. When plugged in, the ESC key will stop blinking and stay a static red, indicating that the keyboard is charging. Once fully charged, the red light will turn off and the ESC key's backlight will change to the same color as the setting. The keyboard can be charged in any mode - BT, USB, or OFF modes.
To check the battery power level of the keyboard, press the FN key and the ESC key. The Battery Level Indicator keys will flash, with each key from F1 to F10 indicating 100% of total power. White light will flash if the power is above 20% and red light will flash when the power is below 20%. If all 10 keys light up, this indicates that the keyboard battery is full.