The Xiaomi Mi 8 supports Qualcomm Quick Charge 4+ technology allowing the phone to be charged by USB Power Delivery 3.0 and Qualcomm Quick Charge 3.0 based chargers over the USB Type-C interface. The phone also works fine with certain USB Power Delivery 2.0 chargers such as the Ventev Wallport pd1300 Wall Charger which we observed a total charging time of about 113 minutes. This was just a bit slower when compared to around 110 minutes using its own shipped Mi 18W QC3 Charger in this review. This shows that the Mi 8 can support USB Power Delivery 2.0 just as well as Qualcomm Quick Charge 3.0 for charging.
Once connected to the Ventev charger, the Mi 8 on 0% battery level quickly pulled current to charge at around 15.3 watts (9 volts @ 1.7 amps) over USB Power Delivery. After charging for 43 minutes, the current progressively stepped down and later began to ramp down as the voltage dropped to a 5 volts rail. When the battery was almost full, the current ramped down close to .1 amps over a duration of 1 hour and 53 minutes. Click here to download the trace captured by the GRL-A1 power analyzer to see more details on the entire charging cycle.