The new iPhone models support wireless charging, perhaps one of the few welcome benefits of having a glass back. Apple has also launched an AirPower wireless charging pad that supports simultaneous charging of iPhone, Apple Watch and AirPods. From this, it can be inferred that metal backplanes are basically out of touch with future generations of iPhones, and glass, plastic, etc. will not affect the wireless charging. Back material will become mainstream. Wireless charging will of course be a standard feature on several future iPhones. 

   Understand "input power" and "actual power"

   The wireless charging of the iPhone uses the Qi standard. As long as the product with the Qi logo, no matter which manufacturer's wireless charging pad can charge the device. Qi uses electromagnetic induction to realize wireless charging. The current in the charging board flows through the coil to generate a magnetic field, and the unpowered coil on the mobile phone is close to the magnetic field to generate current to charge the mobile phone.

   The efficiency of wireless charging is probably the biggest concern for most people, and when it comes to efficiency, it's inevitable to introduce power. During wireless charging, there are three powers to understand. The first power is the input power of the wireless charging board, that is, the power input from the electrical energy to the coil of the charging board. The second power is the output power of the wireless charging board coil, which is the power of the magnetic field generated by the current passing through the coil to transmit energy to the outside world. The third power is the actual power when the device is charging.

  Generally speaking, a relationship is: input power > output power > actual power. The wireless charging pad I use has two levels of input and output power. When using a 9V×1.67A=15W charger, it can generate 5V×2A=10W output power; when using a 9V×1.2A=10.8W charger, it can generate 5V×1A=5W output power. There is a 65% - 75% power loss between the output power and the real power, so the maximum real power of the above two output power is 7.5W and 3.75W.

  When you buy a wireless charging pad, be sure to understand its input power and output power, and then consider its actual power and charging speed. For example, the power mentioned by the wireless charging boards currently on the market is usually the output power, while the power claimed by Apple is the actual power. There is a certain gap between the two.

  Recommended reading: "Apple's claimed 7.5W wireless fast charge is actually a very conscientious actual power"

  Used to wired charging, wireless charging does feel slow

  I use the iPad 12W power adapter to power the wireless charging pad, which should generate 5W of output power. The actual iPhone X wireless charging speed is shown in the figure below (minimize the use of the iPhone X during the charging process).

  Charging iPhone X from 0% to 100%, according to PhoneArena's test, it takes 189 minutes or 3.15 hours with the original 5W power adapter; I use this wireless charging pad of mine with the iPad 12W power adapter, it takes 4 hours, especially It took 30 minutes for the last 5% power boost.

  Although from my wireless charging test, its charging efficiency is really worrying, basically maintaining the level of 13% per hour; but with a higher output adapter, the charging efficiency can reach 34% per hour.
But another big takeaway from my testing was to minimize the use of the iPhone X. With the cable charging mode, you can pick up the phone while charging and play with it in various poses. The power cord is still firmly plugged into the Lightning port to continuously supply power to the iPhone.
  But using wireless charging is very different. Once the iPhone and the charging pad are separated by more than one centimeter, the wireless charging stops. Even if you keep the iPhone on the charging pad and use it at the same time, the charged power may be equivalent to the lost power. It feels like it's not charging at all.
  Best experience at bedside and desk
  Wireless charging is not useless either. I think wireless charging will bring you a good experience in two charging scenarios.
  First of all, the first scene is to use wireless charging when sleeping at night. My habit is to brush the time stream before going to bed, and then fumble for the charging cable by the bedside when sleepiness strikes. What's worse is that sometimes when I finally touch the cable, I have no sleepiness at all.
  The nice thing about wireless charging, by comparison, is that I just put my iPhone on the charging pad on my nightstand. It doesn't matter about the charging efficiency during the long night. When you hear a "beep", the iPhone is already charging, you can sleep in peace, and when you wake up, the battery is fully charged.
  The second scenario is that you no longer need to hang the data cable on the Lightning port when you are working, and you can put the iPhone on the wireless charging pad without knowing it, and it is slowly charging.
  I bought a wireless charging pad that can stand on purpose, and one of the nice things about it is that I can use it to charge my iPhone X upright while I'm at work, and I put it next to my computer with Face ID facing my face. In this way, when a push notification arrives to light up the screen, I only need to glance at it, and the phone will be unlocked. I can see the push details without having to touch it. If I need to operate, I can pick up the phone, which is very convenient.

  I have never cared about charging fast enough when I use a wired charger at the office, and the same goes for wireless charging. I removed the power cord from my desk for this reason, but still use it in some emergency quick charging situations.
In terms of portability, the wireless charging pad is obviously not as easy to move and carry without a Lightning cable. When I'm at home on weekends, I switch between various sofas, kitchens, and various life scenes in the bathroom. At this time, cable charging is still the main charging method. And once I enter the bedroom to rest, write in the study, go to work, etc., wireless charging will become my first choice.