GTrusted

You can use an external power bank like the BatPower PD6 to charge the Moto Z Droid since the phone supports USB Power Delivery technology. Earlier we have seen that the Moto Z Droid requested 27 watts (9 volts @ 3 amps) from the AC Adapter that comes with the BatPower PD6 in this review so we wanted to see if the behavior changed when using the BatPower PD6 with the Moto Z Droid.

First we link up the BatPower PD6 to the BatPower USB Type-C Adapter and then to the Moto Z Droid phone using the USB Type-C cable that comes with the BatPower PD6. While the phone's battery is 55% charged, we observe over USB Power Delivery that the BatPower PD6 offers 5 PDO's: 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). Don't expect 90W output that is advertised on the power bank itself given it only supports up to 60W.

We can see that the Moto Z Droid also requests the same 27 watts (9 volts @ 3 amps) as observed during charging with the BatPower PD6's AC Adapter. The phone then goes on to establish this 27W power contract with the BatPower PD6 which is one of the highest power levels that we've seen being requested by a phone using USB Power Delivery.

However we only manage to briefly observe the highest current pulled by the Moto Z Droid from the BatPower PD6 is only about 2 amps which is about 18.4 watts @ 9.2 volts. With a 55% full battery, the Moto Z Droid only starts charging after 50 seconds at 18.4 watts (9.2 volts @ 2 amps) but with a frequent rise and fall in the current as the battery gets charged. The USB Power Delivery behavior seems pretty much the same as our earlier review with the BatPower PD6's AC Adapter which we also did not see the current go over 2 amps, although charging did happen in the first 10 seconds. After that there is never a stable current in between 0.5 to 1.5 amps @ 9.2 volts being provided by the BatPower PD6 power bank to the Moto Z Droid. 

Unfortunately, the BatPower power bank also doesn't really seem to charge the Moto phone in a stable fashion over USB Power Delivery.