We suggest you follow the battery maintenance tips below to maximize your projector’s battery life.
  
Before the battery maintenance tips
BenQ generally warrants a projector battery when used normally for a period of ONE YEAR from the date of purchase of your projector, but this could vary depending on local laws and regulations. For warranty details, please visit the BenQ website for your area.
 
Battery maintenance tips
•It’s generally recommended to charge your projector for at least 3 to 5 hours 
  for the first use. For more detail, please refer to the user’s manual of the 
  BenQ projector you own.
•It’s okay to charge the projector battery overnight. BenQ projector is designed 
  to prevent the battery from overcharging once full.
•Charge and discharge your projector battery at least once a week
•Store the projector properly in the proper environment listed in the user 
  manual
•Low Power Mode doesn’t hurt the projector battery and can extend battery 
  life due to slower battery drain Image brightness will be decreased to 50% 
  when Low Power Mode is enabled or when the projector is not connected to 
  the power adapter.
•Projector battery capacity will deteriorate gradually due to time aging and 
  charge/discharge cycle count. In general, a projector battery should remain 
  at 80 percent capacity for at least a year from the month it is manufactured.
•The battery cannot be user-changed. Please contact your local BenQ 
  service center if you would like to change the battery.
•To check the battery level of the projector, please press the projector menu on 
  the projector remote to access the projector menu. You will see the battery 
  level, which is on the upper right corner.