In the last few years, we have seen a revolution in fast charging technology for smartphones. From the early breakthroughs of the 20W 30W chargers, to the 40W and 60W chargers are quite popular these days. But 2020 has taken us even further, with Xiaomi launching a charger with a capacity of up to 120W, with the promise of fully charging a smartphone’s battery in minutes.
To be able to evaluate this technology in more detail, Android Authority conducted a field test with the Mi 10 Ultra smartphone and Xiaomi’s 120W charger.
Battery charging efficiency
Android Aithority first checks to see if 120W of current is actually going from the charger to the smartphone while keeping this power. The fact is that Xiaomi’s 120W charger actually only delivers 80 watts of power when charging the Mi 10 Ultra smartphone. Perhaps 120W is measured in Xiaomi’s lab, not in actual conditions.
But in reality, Xiaomi chargers’ power waste is quite low, only 7.3%. The reason is that Android Authority has measured the power from the wall as 86.4W and the actual power source entering the smartphone is 80.1W. We can see clearly in the comparison table below.
Huawei’s 40W charger is a waste of 5.5W, but the rate is up to 19% of total power consumption.
How fast is 120W charging?
It should be noted that Xiaomi’s 120W charger only provides the actual power of 80W. Android Authority also tested charging the Mi 10 Ultra smartphone with many chargers with different capacities for a comparison.
As a result, Xiaomi’s 120W music set, even with the actual capacity of only 80W, still has surprisingly fast charging speed. From depleting the battery to 100% in just 21 minutes, and only 3 minutes to charge up 25%. That’s an impressive result when the Mi 10 Ultra has two 2,250mAh batteries for a total of 4,500mAh capacity.
Surprisingly, charging with the 50W charger also offers impressive speeds and is only slightly less than the 120W charger. It takes just 29 minutes to charge from 0 to 100%, and 5 minutes to charge to 25%.
If we compare the 120W and 18W chargers the difference is huge, but comparing 120W and 50W the difference is not that big. It can be seen that Xiaomi’s 120W fast charging technology is more advertising than the level of technological innovation.
Temperature and battery condition
Super-fast charging is great, but not if it reduces battery life. Usually fast charging will make smartphones very hot, and temperature is the main factor reducing battery life. So to pay attention to the temperature when charging quickly is very important.
Android Authority has taken the temperature measurement when charging with 3 different capacity chargers, just as above. As a result, the 120W charger (80W actual) causes the Mi 10 Ultra smartphone to reach a fairly hot temperature, at 43.8 degrees C. It is alarming that if the actual capacity reaches 120W, this number will still be high. much more.
That is a warning level, because the ideal temperature for the battery is just under 40 degrees Celsius. Fortunately, it is fast charging so the time to maintain this high temperature is not too long, only about 10 minutes. But it can still cause concern.
The 50W charger reaches a maximum temperature of 39.1 degrees C, keeping the temperature below the warning level. The early-stage temperature rise when charging is also slower than the 120W charger.
With a standard 18W charger, the temperature doesn’t even exceed 30 degrees Celsius. The difference of up to 14.7 degrees Celsius between 120W and 18W charging is enormous. Therefore, Xiaomi’s 120W fast charging technology will certainly affect the battery life, either more or less.
Is 120W fast charging worth using?
Fast charging has always been the dream of smartphone users. But with 120W fast charging technology, it seems that the benefits it brings are not worth what users have to spend and trade in.
The improved charging speed compared to the 50W charger isn’t too great. However, the temperature exceeds the warning mark and affects battery life. Basically, you can use 120W fast charge in minutes, to increase the battery by a few dozen% without overheating the temperature.
Xiaomi will probably find a way to regulate the temperature and keep it within the allowable range. But that means the capacity will go down, in short. Not to mention production costs and costs will also increase.
So if you have the habit of charging your smartphone overnight to use the next morning for all day, a standard charger or 18W is still the most reasonable. If you need fast charging, the current 50W capacity is more than enough to meet your needs.