Technical Support General features of our chargers:                                                                                                CHARGERS Universal AC input (global charger) Designed to charge 24 volt systems (normally two 12 volt batteries connected in series) UL designed and listed for safe use Standard XLR output connector for use with most powerchairs and scooters (off-board chargers) General info for powerchair and scooter use: Recommeded to disconnect charger from AC power between each use (but may be left connected to AC between uses if needed). There is no output from the charger if a battery is not connected properly or the battery voltage is too low when 1st connected. Do not place anything on top of the charger while in operation. Do not place on a bed or pillow or the like while in operation. Keep away from external heat (heaters, pipes, etc...). Designed to charge batteries at normal room temperatures.  Avoid charging when over 90F or below freezing. If the Power LED light is red then there is a connection problem or battery voltage is too low or a fuse is blown. If the powerchair is not used frequently, it is recommended to charge the batteries monthly for 24 hours each charge. Turn off all power to the powerchair when not in use (turn key off). If the charger does not seem to be working correctly, disconnect from AC power and from the powerchair/scooter.  Then re-connect to powerchair and then to AC power.  If it still does not work correctly (Power LED is red) then contact your provider or email us with your situation. click for charger manual BatteryMaximizerTM  All rights reservied.  BatteryMaximzierTM is a trademark of TruPower LLC