A method for operating a hybrid drive device including an internal combustion engine-generator unit as a range extender, at least one electric machine for driving and for decelerating the hybrid vehicle, and a battery. During operation of the at least one electric machine, the electrical power provided by a generator of the internal combustion engine-generator unit and/or the electrical power provided by the at least one electric machine in regenerative mode for charging the battery is/are controlled and/or regulated in such a way that the electrical charging capacity of the battery is below a predefined limiting value.