Whats the max input wattage can an iphone XR, XS, XS Max for fast charging ?


macrumors newbie
Original poster
Nov 12, 2018
I am trying to purchase a third party USB-C fast charger. I was wondering what the the maximum wattage the newer iphones can draw through USB-C power drive 3.0

There chargers I am considering are:

Aukey PA-Y16

- USB-C Output 1/2 (Power Delivery 3.0): (PDO) 5V 3A, 9V 2A; (PPS) 3V–5.9V 3A, 6V–11V 2A

- 36W

This charger supports 18 watts per USB-C port so I am wondering does the new iphones need more than 18 watt for fast charging? I want to be able to fast charge on both ports at the same time.

The second charger I am considering is Aukey PA-Y10

USB-C Output: (PDO) 5V 3A, 9V 3A, 12V 3A, 15V 3A, 20V 2.3A; (PPS) 3V–16V 3A

It has only one USB-C port but it's wattage is 46 Watt. So would it charge faster the the above one ?

All I want to know is that how much wattage change the new 2018 iphones can take so I don't unnecessarily go for higher wattages.


macrumors member
Dec 14, 2017
I consistently read maximum input to the iPhone for the wireless charging iPhones is 7.5 watts, but that’s only coming from the charger manufacturers or 3rd parties, not from Apple.

I have a device that measures voltage and amps coming out of the charger but not at or in the iPhone. The two Anker car chargers I’ve tried for wireless charging are 5 volt and 9 volt, but the amperages change while charging so the wattage output seems to be about the same, but I can’t do both at the same time to know exactly. Both are specified higher than 7.5 watts, as I recall 12 and 19 watts per USB out (2). The 9 volt charger seems to do better than the 5 volt charger with the longer cord needed to reach the outlet in my center console. I don’t know enough about electricity measurements vs. cord resistance to know if the wattage measurements at the upstream end of the cord is what reaches the downstream end or not, but I’m guessing not. My experience with auto and boat stereo installations is cord gage is very important when powering amps with long power cord runs. For the center console outlet I’m using an Amazon Basics 6 foot cord rated for 5 volts at 3 amps which equals 15 watts so should be 2 times what the iPhone can use
AmazonBasics USB Type-C to USB-A 2.0 Male Cable - 6 Feet (1.8 Meters) - Black https://www.amazon.com/dp/B01GGKYN0A/ref=cm_sw_r_cp_tai_o3a7BbN56F0ZN

You can find links to the chargers and device I use to measure in this post I started.
Wireless Car Charger

There is an app I saw in the App Store that compares cords and chargers, based on time to get 2% battery level increase, but I haven’t tried it yet. I guess 99 cents isn’t much considering how much wireless chargers, cords, and phone holders cost.


macrumors 6502
May 20, 2010
I tested last night. Killed both my wife's and my Pro Maxes. Then put hers on the 18W from the box and put mine on a 30W Power Bank. After a half hour I was 54% and she was 50%. Didn't seem like much of a difference. I might try again with a 30W wall charger instead of a Bank. Or maybe the throttling after 50% is that considerable.