Method for determining an aging condition of a battery cell in a hearing instrument

A state of health of a battery cell used in a hearing instrument is ascertained. For each of a plurality of charging cycles, a battery manager of the hearing instrument ascertains a charge transferred to the battery cell and a number of charging characteristic values that provides information about the change in a state of charge of the battery cell brought about by the charge. Based on the transferred charge and the charging characteristic values a capacity characteristic value is ascertained that forms a characteristic variable for a present charging capability of the battery cell. A signal processor averages respective capacity characteristic values of at least some past charging cycles at a specific time and calculates an averaged charging capacity. The averaged charging capacity is compared with a reference value representing an original capacity of the battery cell to determine the state of health of the battery cell.