1.please make sure that the charger is in good condition when use.After receiving it,check if the charger is deformed or the internal parts are loose,something rattling around inside or not;if exist,please do not use it and asking seller for solutions directly
2.Make sure that city power input voltage is compatible with the charger:refer to the condition diagram on the manual,make sure the correct connection
3.Please avoid that the battery is over discharged,as this will make charging difficult and the battery will likely not been charged.This charger has a repair function,and the battery can be repaired while charging if the battery is not dead or is almost completely discharged.Normally charge it in Auto mode for several hours and it will reset automatically.If the battery is completely discharged and cannot be charged by this charger,p