Method for charging an energy store of a vehicle using a charging apparatus which provides a charging current (I L) and a charging voltage 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 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. - 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 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.