A hearing aid system includes a hearing aid with a rechargeable battery and a first data memory for storing operating data, and a charging station with a nonvolatile second data memory. The charging station charges the battery of the hearing aid at least intermittently while the hearing aid is arranged in a charging position. The hearing aid transmits operating data from the first data memory to the charging station when the hearing aid is arranged in a transmission position. The charging station stores operating data transmitted from the hearing aid in the second data memory, and the charging station transmits operating data stored in the second data memory to the hearing aid. A computer unit of the hearing aid adjusts at least one parameter relating to signal processing of the hearing aid based on the operating data transmitted from the charging station to the hearing aid.