# Power setup Open the *Vehicle Setup* tab and select the *Power* menu. ## Calibrating the power sensor > **Note** Power sensor calibration should be done with the battery pack connected to the drone. 1. Set the *Number of cells* parameter according to the number of cells in your battery (*3* for the Clever 4 drone). 2. Calculate the voltage divider: * Measure voltage across the battery (you may use a battery voltage tester for that). * Press the *Calculate* button next to the *Voltage divider* label. * Put the battery voltage into the prompt and click *Calculate*. * Press *Close* to save the calculated value. Further reading: https://docs.qgroundcontrol.com/en/SetupView/Power.html. ## ESC calibration > **Warning** **Never attempt ESC calibration with propellers on!** In some cases the motors will start spinning with maximum speed. 1. Make sure the battery is disconnected and the propellers are not mounted. 2. Press *Calibrate*. 3. Connect the battery when prompted. 4. Wait for the *Calibration complete*. Further reading: https://docs.px4.io/v1.9.0/en/advanced_config/esc_calibration.html.