A method for controlling a system comprising a power-tool and at least one battery having at least one energy storage cell, wherein the system comprises at least one acceleration sensor for detecting at least one acceleration value in an X, Y and Z direction, at least one piezoelectric sensor, a controlling device, signal transmitter as well as a device for measuring a voltage, including the method steps: - Determining vibration values acting upon the system by detecting accelerations values within a predetermined range; - Determining that the system is free-falling by detecting an acceleration value in the X, Y and Z direction being equal to a predetermined range; - Determining an impact of the system by detecting at least one acceleration value in the X, Y and Z direction exceeding a first predetermined threshold value, characterized by the method steps: - Determine a traveling distance between detecting an acceleration value in the X, Y and Z direction being equal to a predetermined range and detecting at least one acceleration value in the X, Y and Z direction exceeding the first predetermined threshold value; - Determining a shock value by means of the at least one piezoelectric sensor or the at least one acceleration sensor; - Detecting a first and second voltage value of the at least one energy storage cell by means of the device for measuring a voltage within 60 seconds; and - Sending out a first signal by means of the signal transmitter if the accelerations values within the predetermined range for determining vibrations exceed a first predetermined threshold value for a first predetermined time period, the determined drop height exceeds a first predetermined threshold value, the detected value for determining a shock exceeds a first predetermined threshold value or a difference value between the first and second voltage value exceeds a first predetermined threshold value. - Determining vibration values acting upon the system by detecting accelerations values within a predetermined range; - Determining that the system is free-falling by detecting an acceleration value in the X, Y and Z direction being equal to a predetermined range; - Determining an impact of the system by detecting at least one acceleration value in the X, Y and Z direction exceeding a first predetermined threshold value, characterized by the method steps: - Determine a traveling distance between detecting an acceleration value in the X, Y and Z direction being equal to a predetermined range and detecting at least one acceleration value in the X, Y and Z direction exceeding the first predetermined threshold value; - Determining a shock value by means of the at least one piezoelectric sensor or the at least one acceleration sensor; - Detecting a first and second voltage value of the at least one energy storage cell by means of the device for measuring a voltage within 60 seconds; and - Sending out a first signal by means of the signal transmitter if the accelerations values within the predetermined range for determining vibrations exceed a first predetermined threshold value for a first predetermined time period, the determined drop height exceeds a first predetermined threshold value, the detected value for determining a shock exceeds a first predetermined threshold value or a difference value between the first and second voltage value exceeds a first predetermined threshold value.