The invention discloses a charging control device comprising a voltage converter, a protocol interface module and a control module. The charging control device, by acquiring the power information of an input power source and the charging power or charging current information of other units that extracts power from the same power source, calculating and adjusting the maximum output capability of the input power source in real time, and ensuring that a power output request sent by the protocol interface module does not exceed the maximum output capability of the input power source, solves the problem that a current mainstream fast charging protocol does not take account of the limitations and dynamic changes of the input power source and causes a charging device extracts excessive power from the power source, and ensures the safe operation of the input power source.