Let's now see what happens when we charge the phone using the Apple 12W USB Power Adapter (5.1 volts @ 2.4 amps) commonly found with iPads. The charger send charging pulses to more efficiently charge the phone and starts off by pulling 1.3 amps which is more than the 1 amps that can be pulled from the Apple 5W USB Power Adapter.
We can see that the current steadily decreases al the way down to .06 amps when the battery is close to 100%.
It takes less than 110 minutes to fully charge with power starting at 6.5 watts and then falling all the way down to .3 watts when the battery is near 100% full. This compares to the 160 minutes needed to fully charge the iPhone 7 with the Apple 5W USB Power Adapter as seen in this review.