GTrusted
The Nubia Z17 supports USB Power Delivery but has problems trying to charge with many USB Power Delivery chargers like the Apple 87W USB-C Power Adapter when the phone has a dead battery. We illustrate this by looking at the USB Power Delivery protocol negotiations through the Granite River Labs GRL-USB-PD-A1 analyzer between the Nubia Z17 and Apple 87W USB-C Power Adapter when the charger is first connected to the phone using the Apple's USB Type-C to Type-C cable that came with the charger.
We first see that the Apple 87W USB-C Power Adapter repeatedly advertises only a single 12 watts (5 volts @ 2.4 amps) power profile without any response from the Nubia Z17 which has zero charge in its battery.
After a long repetitive 12 watts (5 volts @ 2.4 amps) display from the Apple charger, the Nubia Z17 can be seen to finally request this power which the charger then accepts.
After multiple Discover Identity requests have been made, the Apple 87W USB-C Power Adapter advertises not only the 12 watts (5 volts @ 2.4 amps) it initially declared but also two other power profiles: 27 watts (9 volts @ 3 amps) and 86 watts (20 volts @ 4.3 amps).
The Nubia Z17 follows up to still request the same 12 watts (5 volts @ 2.4 amps) which the Apple 87W USB-C Power Adapter also complies. The Apple charger then goes on to initiate Discover Identity’s and SVIDs’ during communication with the Nubia phone.
However we later observe both the Apple 87W USB-C Power Adapter and Nubia Z17 keep on cycling through the same initial power transactions in the negotiation process.
With never a stable power level seen from the power graph, we can say that charging doesn't really happen between the Apple 87W USB-C Power Adapter and Nubia Z17 phone at 0% battery.
