Notebook PC's with dual-role power capabilities like the Acer Chromebook R 13 comes in handy for charging other compatible devices when there's just no access to AC power as well as being able to be charged itself. Since the Apple iPhone X supports USB Power Delivery 2.0 based charging similar to the Acer Chromebook R 13, we'll see here how they work when connected over a Apple USB-C to Lightning Cable.
Given that Apple iPhones supporting USB Power Delivery can only consume and not supply power, the Acer Chromebook R 13 will be acting as a power bank to the Apple iPhone X, thus consuming the Chromebook's own battery charge to support charging the iPhone.
With a 50% charged battery on the Apple iPhone X, we could see the iPhone began drawing around 7.6 watts when connected to the 97% charged Acer Chromebook R 13. The power drawn then steadily dropped to about 6.7 watts as lower current was pulled by the iPhone. With this level of charging, it only allows the iPhone to charge slightly faster than using its own 5W USB Type-A charger.
Click here to download the trace captured by the GRL-A1 power analyzer to see more details on how the Acer Chromebook R 13 at 97% battery, charged the Apple iPhone X at 50% battery charge.
Download the A1 software from Granite River Labs to view the trace.