For all Dust Busters and Scum Busters other than the Fire Storm line. For newer, CEC chargers, please go here. The recommended charge time is a minimum of 16 hours. Charging overnight may not be the same as charging for 16 hours. ( CEC chargers will charge in 9 hours, see above) Make sure the On/Off switch is in the "O" position . The unit will not charge if the switch is in any other position. While charging the charge indicator light (if equipped) will be illuminated. The batteries used in the Dust Buster and Scum Buster will not develop a memory. While charging the unit might get warm to the touch. This is normal and not a reason for concern. The Dust Buster or Scum Buster can remain on the charger indefinitely without damage or concern. You can not overcharge the Dust Buster or Scum Buster batteries using the charger provided. The average run time of a fully charged Dust buster with a clean filter is 8-10 minutes . For a Scum buster it will be 25-30 minutes. Please note that a Dust Buster or Scum Buster is not designed to vacuum or scrub an entire room or house on one charge. Run times will vary depending upon model. Your unit may require several charges  before reaching the average run time. For best results empty and clean your unit after each use. Return the unit to the charger after each use. The battery use very little electricity and in most cases consume less than half the amount of electricity used by a common night light. To review troubleshooting procedures for the Dust Buster and Scum Buster please click here