Does the AppleWatch support fast charging? Why not do more power?

Apple Watch, AirPods and other gadgets only charge a few watts. Is that fast enough? Why can't the Apple Watch do more? Today we're going to talk about that.

Charger has tested the charging data of several Apple Watches. Here is the most recent Apple Watch Ultra, for reference. Take out the case inside the object, in addition to the case, and Apple Watch Ultra magnetic suction charging line and a few manuals. 

The USB-C port is the input port of the charger for Apple Watch Ultra, which can be adapted to mainstream chargers in the market. The middle of the wireless magnetic charging area is concave design, better fit the table back. The wire is of high density braided design, with better wear resistance and bending resistance. The side of the shell is printed with charging cable parameter specification input 5V1A. 

The Apple Watch Ultra battery has a full charge voltage of 4.47V, capacity of 542mAh, discharge platform of 3.85V, energy of 2.094Wh, battery model A2749. The cell is made by Huizhou Desai Battery Co., LTD., a high-voltage, high-energy-density battery with a similar material formula to that used in mobile phones.

The Apple Watch Ultra charging mode adopts wireless magnetic absorption charging. The power receiving coil at the watch end is directly integrated into the watch bottom case. The coil is very thin with only peripheral winding, so it is speculated that the power transmission efficiency of wireless charging is not high.

• How powerful does the Apple Watch actually charge?

Use the original magnetic absorbing charging cable of Apple Watch Ultra with Apple 35W USB-C charger to charge, and access the POWER output data of the charger through the USB-C end of the charger through power-Z.

In the first 11 minutes, the charging power is basically stable at about 5W, and then it is charged at about 0.13W. After 1 minute, it is charged again at about 5W. After this cycle for 8 times, the power of 4.3W drops continuously to 3W in 38 minutes to charge to 50 minutes, and then it enters the trickle charge until the end. The total time is about 1 hour and 21 minutes. The whole input power is 3.935Wh. In the middle of charging, there is a similar "stop charging" phenomenon, which may be to avoid overheating protection.

Using the original magnetic cable and 35W charger to charge 50% in half an hour and 90% in an hour, the total charging time for the Apple Watch Ultra is 1 hour and 21 minutes.

Because Apple Watch Ultra uses wireless charging, there is a problem of "power transfer efficiency". The USB-C power data cannot be directly converted into the charging power of Apple Watch Ultra.

summarize

This charging roundabout discussed the charging of small devices like Apple Watch Ultra. Wireless charging is very suitable for smart wear, wireless audio and other low-power charging devices due to the convenience of charging with drop and adsorption. However, due to the size and portability, the batteries of such devices are usually not large. Wireless charging is relatively low in power and efficiency. Efficiency value and equipment volume also restrict the charging power is not large, and can not blindly increase the power.

But in terms of actual charging speed, the Apple Watch Ultra is already capable of charging 50% in 30 minutes, making it a decent fast charging experience without having to increase the charging power further.