When the Mi 9 was first announced, Xiaomi also said that this phone can use their very own 20W Mi Wireless Fast Charger. If you buy the Mi Wireless Fast Charger, you also get a 27W charger in the box. However, it’s a piece of hardware that is really difficult to find here in Malaysia – but we got our hands on one.
How did we get it? Well… It is technically available for sale in both Lazada and Shopee. While I understand some people might say the price is too high, you need to know what you actually get two chargers inside. One wired, and one wireless – but it’s not what you expect. Let me explain.
The box itself is rather simple this time around. Looking at the front, I thought it is a lightbulb – but nope, it’s the top view of the wireless charger itself.
At the back, there are details on the product itself. Reading the little piece of spec sheet here you can see that it takes a maximum input of 20V at 1.35A and outputs 20W maximum. We’ll come back to the math later on.
Digging out everything, you get some simple documentation with a charging brick, a USB-C cable, and the wireless charging pad itself. Some might ask – why is there a charging brick inside? The answer is simple – let us explain further.
Doing the math
Let’s first look at the included power brick. This power brick is capable of outputting multiple different power ratings with its respective voltages and amperages. We’re only interested in the last one – 20V at 1.35A. Hmmm… 🤔
By looking at the back of the Mi Wireless Fast Charger pad itself, we see can see that its maximum input is at 20V 1.35V. Doing a quick calculation here shows that its maximum input power is 27W while its maximum output power is 20W. That means the included power adapter is made to be used with the wireless charger!
But that also means the power adapter is capable of fast charging the Mi 9 with 27W! You get two fast chargers with the price of one – 27W wired fast charging and 20W wireless fast charging.
Looking at the Mi Wireless Fast Charger pad itself
It’s actually pretty grippy this time around. I took it out of the box for a while and it immediately got a bit of lint and dust on it. That is because the top and bottom parts are covered in silicon – essentially becoming an eraser.
This thing is so grippy that the Mi 9 really doesn’t move at all, which is much better than the one included with the Mi Mix 3 which slid around and misaligns itself with the charging coils.
Around the gap between the top and bottom part, we can see slits. These slits are presumably for ventilation as wireless charging technology is rather inefficient and things can get heaty. Having these holes mean that the components inside can breathe and prevent overheating.
Charging speeds compared
We use our usual methodology in testing the battery charging speed. We take the data points from 15% battery to 100%.
For a quick glance, this is the overall charging speed comparison that we have. In this graph, we lumped both wired and wireless charging alongside with commonly-found 5V 2A wired charger and 5W wireless chargers as a baseline.
Separating the graph into two parts, we are able to further analyze the differences in charging speed. Let’s look at the wired chargers first.
From here, it’s quite interesting to see that both QuickCharge 3.0 and Xiaomi’s own 27W charger are very close in comparison. By looking at the data gathered, it can be said that the Mi 9 isn’t actually taking in 27W of power to quickly charge itself up, but instead charging at 9V 2A in accordance to Qualcomm QuickCharge 3.0 specs.
However, the story changes when we look at the wireless charging speeds. I can’t help but notice its linearity from the beginning until the end. The 20W Mi Wireless Fast Charger is obviously faster by a significant amount. But then again, even the 20W Mi Wireless Fast Charger is easily defeated by the standard 5V 2A charger.
Here’s a table to summarize all of the charging times with its respective charge levels.
|Mi 9 battery charge level||Time taken from 15% battery (minutes)|
|Wired charger||Wireless charger|
|Xiaomi 27W wired fast charger||Qualcomm QuickCharge 3.0 (18W)||Standard 5V 2A (10W)||Xiaomi 20W wireless fast charger||Generic 5V 1A (5W)|
Wrapping up the Xiaomi Mi Wireless Fast Charger review
This is quite an unusual review from us – but we are just presenting scientific data as usual. From this experiment, we found out that the 27W wired fast charger actually charges the Mi 9 using Qualcomm QuickCharge 3.0 standards but the wireless fast charger is where the money is at.
That is okay since the Mi Wireless Fast charger needs to be plugged into the 27W wired fast charger to output that 20W wireless charging power anyway.
For me personally, I’ve made the switch to wireless chargers at home anyway. However inefficient it may be, I love the fact that I can just put my phone on the wireless charging stand or dock and my phone will charge itself – especially useful if you are using an IP68 phone that has water in the charging port. 😏