The present application provides a charging system having a charger and a battery. The charging system provides a quick-charging mode and a normal-charging mode. The quick-charging mode may be activated to charge the battery if certain conditions are met and the charging system may also have an indicating device for indicating when the quick-charging mode is finished. More specifically, the charger of the present application provides selective charging modes and provides an ultra-quick charging solution which may be controlled by the changes in the temperature of the battery and which can increase the charging power to quickly provide enough energy to finish a work task.