Long Press the on/off button for 2-3 Seconds to Brightness. Press one to 60% brightness. Press again to 30% Brightness. Press again to strobe mode. The battery life is up to 3 hours, it will last 1.5 hours of battery life at the highest brightness. The battery indicator light will show red when charging, and will turn into green when fully charged. It will take 2 hours to be fully charged. Read Less