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The Apple iPhone 8 now supports fast charging using USB Power Delivery technology over its Apple Lightning connector. Let's see how well this newest iPhone charges with the USB Power Delivery based Apple 29W USB-C Power Adapter that originally came with the Apple MacBook (Early 2015).
Note you will need to use a Apple USB-C to Lightning Cable in order to connect between the iPhone and Apple charger.
Looking at the USB Power Delivery negotiations, we can see that the Apple 29W USB-C Power Adapter repeatedly displays 12 watts (5 volts @ 2.4 amps) and 29.6 watts (14.8 volts @ 2 amps) power profiles when connected to the 24% charged Apple iPhone 8.
The Apple iPhone 8 first requests to pull 12 watts (5 volts @ 2.4 amps) from the Apple charger which it then accepts.
We also observe after some time that the Apple iPhone 8 finally requests and establishes the highest 29.6 watts (14.8 volts @ 2 amps) power contract with the Apple 29W USB-C Power Adapter to speed up charging. Note that after the initial 5 volts @ 2.4 amps, the iPhone selects 14.8 volts @ 2 amps after the Apple charger initiates Discover Identity, SVID's, and unstructured VDM's.
When initially plugged in at 24% battery and turned on, we can see in the first 10 seconds the Apple iPhone 8 pulls power of around 6 watts (5 volts @ 1.2 amps) to 13.3 watts (14.8 volts @ 0.9 amps). The phone then gets more stable charging at around 11.8 watts (14.8 volts @ 0.8 amps) but the current later bounces between 0.6 to 0.9 amps at 14.8 volts as charging continues.
The Apple iPhone 8 can charge faster with the Apple 29W USB-C Power Adapter using USB Power Delivery than the 5 watts based charger that comes with the iPhone.
