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 (HD) 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 (HD) 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. <EOS>