You sure can.  When you hold "+" button for  more than 3 seconds it will go to auto-shutoff hours adjust mode, the red dot will flash 8 times(default).  At this time, if you press "-" button once, it will decrease the time one hour, also the red dot will flash once. If you press "+" button, the hour will increase one hour (red dot will flash once).  You can adjust the time from 2 to 8 hours. When you hold "+" button for  more than 3 seconds again, it back to brightness adjust mode (regular mode).   You can verify the current setting by holding the “+” button for more then 3 seconds.  The number of flashes will indicate the number of hours.  e.g. 3 flashes = 3 hours.