NOVELTY - The method involves supplying primary charging direct current (DC) (I1) and secondary charging DC (I2) to the charge storage device (3). The primary charging direct current is generated by the DC-DC converter (7) directly from power produced by external photovoltaic cell (4) of the electric car (2). The secondary charging DC is generated from energy in a power supply network (11). The primary charging DC and the secondary charging DC are set so as to be adjusted in dependence on the total charging current of the charge storage device.    USE - Method of operating charge storage device e.g. rechargeable battery or fuel cell of electric car (claimed) such as electric passenger car and electric truck.    ADVANTAGE - The charge storage device of electric car can be operated energy-efficiently and/or cost efficiently. The DC-DC converters operate effectively, so that only low electrical losses occur when feeding the primary charging DC. The conversion loss can be minimized by the direct conversion of the current by the photovoltaic system to the charging current. The efficiency of DC voltage converter and efficiency of the rectifier can be used to adjust the primary charging DC and the secondary charging DC so as to provide an energy-efficient charging with low conversion loss in the DC-DC converter and the rectifier. The dynamically maximum available current from the photovoltaic cell is used for charging the charge storage device of electric car, so that conversion losses can be minimized. The efficiencies of the DC-DC converter, the rectifier and the inverter can be changed depending on the changing currents or voltages.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following:    (1) device for loading charge storage device of electric car; and    (2) electric car.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of the device for loading charge storage device of electric car. (Drawing includes non-English language text)    Electric car (2)    Charge storage device (3)    Photovoltaic cell (4)    DC-DC converter (7)    Power supply network (11)    Primary charging DC (I1)    Secondary charging DC (I2)