NAXCharge is watching for a power source. Connect your charger and detection will start instantly.
Enter your device's battery Wh above. Wrong capacity is the #1 reason watt estimates are off.
Plug in your original charger, keep the screen at fixed brightness, then start the timer.
Let charging stabilize past the initial surge for a reliable %/min reading.
From your charger label or, best, a USB-C meter. Exact charger watts require external hardware.