Having tested with the Macbook, we will see how the RAVPower Xtreme 26800mAh Portable Charger with Type C Port + 30W Type-C AC Charger performs with a Windows-based PC like the Dell XPS 12 9250 2-in-1 Laptop. Similarly we will use the battery portion of the charger to charge the USB Power Delivery enabled Dell XPS 12 9250 2-in-1 Laptop over its USB Type-C connector.
The RAVPower Xtreme 26800mAh Portable Charger with Type C Port + 30W Type-C AC Charger battery kicks off the USB Power Delivery negotiation by declaring that it offers only a single 15 watts (5 volts @ 3 amps) power profile to the PC. The PC requests only 4.5 watts (5 volts @ 0.9 amps) from the battery which it accepts.
The charger battery later advertises not only the 15 watts (5 volts @ 3 amps) it initially declared but also four other power profiles: 27 watts (9 volts @ 3 amps), 28.8 watts (12 volts @ 2.4 amps), 31.5 watts (15 volts @ 2.1 amps), and 30 watts (20 volts @ 1.5 amps). The Dell XPS 12 9250 2-in-1 Laptop then requests to draw 30 watts (20 volts @ 1.5 amps) which the charger battery complies.
However, soft resets eventually terminates charging.
When the charger battery resumes communication after some time, only a single 0.25 watts (5 volts @ 0.05 amps) power profile is offered to the PC. The PC follows up by requesting to pull 0.25 watts (5 volts @ 0.05 amps) from the charger battery which it accepts. After a hard reset is done, the charger battery can be seen constantly showing that it supports only a single 0.25 watts (5 volts @ 0.05 amps) power profile.
After a while the Dell XPS 12 9250 2-in-1 Laptop does request to pull 0.25 watts (5 volts @ 0.05 amps) which is accepted by the battery. This is again followed by the same resets as initially observed.
When the Dell XPS 12 9250 2-in-1 Laptop is being charged on a fully drained battery, we can see that charging happens at 30 watts (20 volts @ 1.5 amps) for the first 20 minutes and then drops down to only 0.25 watts (5 volts @ 0.05 amps).
We can confirm that the RAVPower Xtreme 26800mAh Portable Charger with Type C Port + 30W Type-C AC Charger's portable battery was unable to properly charge the Dell XPS 12 9250 2-in-1 Laptop correctly using USB Power Delivery.