Method for charging an energy store of a vehicle using a charging apparatus which provides a charging current (I L ) and a charging voltage (U) at an operating point, wherein the charging apparatus has a plurality of structurally identical energy supply modules connected in parallel, characterized by the following method steps: - in an approximation step, an approximation of the efficiency (η N ) of an individual energy supply module is determined on the basis of an output voltage (U) and an output current (I M1 , I M2 , I MN ) of the energy supply module , wherein the approximation is carried out by means of linear approximation or quadratic approximation or cubic approximation; - in an optimization step which follows the approximation step, a distribution of the charging current (I L ) to the energy supply modules connected in parallel, in the case of which the charging apparatus has a maximum overall efficiency, is respectively determined for a plurality of predefined operating points, wherein the overall efficiency is optimized on the basis of the approximation of the efficiency (η N ) of an individual energy supply module , as determined in the approximation step, wherein a number (n) of active energy supply modules is determined as the starting point for the optimization and the charging current (I L ) is equally divided among the active energy supply modules , wherein the distribution of the charging current (I L ) to the active energy supply modules starting from the starting point is determined by means of a gradient method; - in a charging step which follows the optimization step , a distribution of the charging current (I L ) to the individual energy supply modules of the charging apparatus , in the case of which the charging apparatus has a maximum overall efficiency, is selected on the basis of a predefined charging current (I L ) and a predefined charging voltage (U). - in an approximation step, an approximation of the efficiency (η N ) of an individual energy supply module is determined on the basis of an output voltage (U) and an output current (I M1 , I M2 , I MN ) of the energy supply module , wherein the approximation is carried out by means of linear approximation or quadratic approximation or cubic approximation; - in an optimization step which follows the approximation step, a distribution of the charging current (I L ) to the energy supply modules connected in parallel, in the case of which the charging apparatus has a maximum overall efficiency, is respectively determined for a plurality of predefined operating points, wherein the overall efficiency is optimized on the basis of the approximation of the efficiency (η N ) of an individual energy supply module , as determined in the approximation step, wherein a number (n) of active energy supply modules is determined as the starting point for the optimization and the charging current (I L ) is equally divided among the active energy supply modules , wherein the distribution of the charging current (I L ) to the active energy supply modules starting from the starting point is determined by means of a gradient method; - in a charging step which follows the optimization step , a distribution of the charging current (I L ) to the individual energy supply modules of the charging apparatus , in the case of which the charging apparatus has a maximum overall efficiency, is selected on the basis of a predefined charging current (I L ) and a predefined charging voltage (U). <EOS>