Q2686H and AT+ADC


I’m using the Q2686H with the first official release - firmware. To monitor the batterie voltage I use the at+adc command. The first of the 3 response values is the batterie voltage. Unfortunately the value of the battery voltage is often wrong (sometimes values like 7000, or simply several hundret millivolts beside the correct value). If I vary the input voltage (I use a power supply instead of a battery) sometime nothing is changing on the output value from the at+adc command. What I have done wrong?

Best regards,