Once we connect the BatPower PD6's AC Adapter with the Nubia Z17 through both the BatPower round to rectangle connector adapter and BatPower USB Type-C Adapter, the BatPower adapter repeatedly claims to support 5 different USB Power Delivery power profiles: 15 watts (5 volts @ 3 amps), 27 watts (9 volts @ 3 amps), 36 watts (12 volts @ 3 amps), 45 watts (15 volts @ 3 amps) and 60 watts (20 volts @ 3 amps) over the USB Type-C connector. Since only up to 60W is being offered, it doesn't comply with the 90W output advertised on the adapter's casing.
The Nubia Z17 can be seen to request an initial 15 watts (5 volts @ 3 amps) of charging from the BatPower adapter which it accepts.
The Nubia Z17 later requests and establishes 27 watts (9 volts @ 3 amps) power contract with the BatPower adapter allowing the phone to charge much faster.
We can also see that the Nubia Z17 starts charging from 11% battery at around 10 watts (5 volts @ 2 amps) in the first 40 seconds. After that the phone finally draws 15 watts (5 volts @ 3 amps) from the BatPower adapter.
Reaching 60 seconds, the voltage level goes up to 9 volts but the phone only pulls about 1.2 amps current from the charger. The phone then eventually charges at around 15.9 watts (12.2 volts @ 1.3 amps). While we didn't observe the phone get close to 27W or even 36W of charging which was established in the USB Power Delivery negotiations, the BatPower PD6's AC Adapter is able to charge the Nubia Z17 at just slightly lower power compared to using the phone's own Qualcomm Quick Charge charger.