The keyboard's battery life is up to 80 hours of uninterrupted use — about 3 weeks of normal usage (without backlight). 

The backlight can affect battery life depending on the brightness and color. However, power-saving features like turning the backlight off after 30 seconds of inactivity (and turning it back on with your first touch) help improve battery life.  

Actual working time on a battery with the backlight on can range from 8 to 15 hours of continuous use, leading to 2-4 days of normal usage (including breaks in keyboard usage).