Method for operating a sensor device for monitoring a drive system, which has a supply battery for supplying power to the sensor device , a sensor unit , with which operating state data of the supply battery can be detected, and a communication unit , with which the operating state data can be transmitted to an evaluation system , wherein - operating state data of the supply battery is detected with the sensor unit at different measuring time instants (t 1 , t 2 ), - the operating state data and machine measuring data acquired by the sensor unit is transmitted to the evaluation system with the communication unit characterised in that an energy demand of the sensor device is determined by the evaluation system and the operating state data and the energy demand are used to generate a recommendation for action for optimized operation of the sensor device , wherein in the evaluation system battery type data of various battery types is provided, wherein a preferential battery type is determined by the evaluation system on the basis of the battery state data, the energy demand and the battery type data, and as a recommendation for action the operation of the sensor device is generated with a battery of the preferential battery type as a supply battery , wherein the battery state data is evaluated by means of the evaluation system with statistical methods, wherein the energy demand is determined from time intervals (Δt), which are allocated to the operation of the sensor device in various operating modes (M1 to M4) in each case and powers which are required for the operation of the sensor device in the operating modes (M1 to M4) respectively, wherein battery voltages (U) and battery temperatures (T) of the supply battery are detected as operating state data. - operating state data of the supply battery is detected with the sensor unit at different measuring time instants (t 1 , t 2 ), - the operating state data and machine measuring data acquired by the sensor unit is transmitted to the evaluation system with the communication unit an energy demand of the sensor device is determined by the evaluation system and the operating state data and the energy demand are used to generate a recommendation for action for optimized operation of the sensor device , wherein in the evaluation system battery type data of various battery types is provided, wherein a preferential battery type is determined by the evaluation system on the basis of the battery state data, the energy demand and the battery type data, and as a recommendation for action the operation of the sensor device is generated with a battery of the preferential battery type as a supply battery , wherein the battery state data is evaluated by means of the evaluation system with statistical methods, wherein the energy demand is determined from time intervals (Δt), which are allocated to the operation of the sensor device in various operating modes (M1 to M4) in each case and powers which are required for the operation of the sensor device in the operating modes (M1 to M4) respectively, wherein battery voltages (U) and battery temperatures (T) of the supply battery are detected as operating state data. <EOS>