It should be an iphone xs max with 18 watts of charge. When using Apple's 30W USB PD charger to charge the iPhone XS Max, it took only half an hour to charge the phone to 50%, but it took more than two hours to fully charge.
In the first 30 minutes of this stage, except for just charging, the voltage and current are maintained in a relatively high state, at this stage, the power is relatively large, and the power will increase relatively fast. As the saturation of the cell phone battery increases, the current will start to drop, and the power will naturally drop. At about 1 hour and 5 minutes, the voltage also dropped, and the original 9V PD gear was directly transferred to 5V PD gear.
1, XS Max can support 18W, or 30W fast charge power;
2, you can also use the iPad included 12W charging power charger for iPhone charging, 12W full time roughly takes about 2 hours;
3. If you need to trigger 18W or even peak 20W fast charging power, you need to have a fast charging head that supports the PD protocol and a data cable that uses Lightning interface to USB-C interface. Only these two are available at the same time can you achieve fast charging of iPhone.