Hello,
I own X Compact and it is supposed to support Quick Charge 2.0. I've done some measurements while testing the QC and results are a little bit strange. First of all, to clarify, I am talking about charging between 0-60%, because later the charging obviously slows down.
So, I've noticed that the X Compact charges about 12% it 10 minutes. That's not as fast as it should be, I believe. I performed two charge sessions - both were from 5% up to 100%, but let's talk about charging just to 60% as I mentioned before. During the first session the phone was powered off. The voltage was varying from 8,71 to 8,75 volts. That's fine, let's assume it was 9V (given that QC 2.0 can use 9V and 12V). On the other hand, the amperage was quite low. It varied from 1.05 to 1.19 amps. So, the overall power was ranging somewhere between 9,7-10,3 watts. Basically, 10 W. That doesn't seem like QC, does it? 10 watts is the standard for QC 1.0, as far as I'm concerned.
Moving on to the second session. The phone was turned on during the test, but I wasn't using it. There were some standard processes running in the background and Bluetooth and Wi-Fi were on, nothing special. The phone was powered on but idle. The wattage throughout the charging from 5-60% was actually the same as in the previous case. But the voltage and current were different. The voltage was about 7-7,4 V and the current was about 1,3-1,5 A. Again, the output was 10 W. Maybe the changes weren't significant, but still - I am curious why they occured.
There is one more thing worth metioning that I am concerned about. The QNOVO technology. If the whole charging (from 5-100%) is taken into account, the time it took to charge the phone was almost the same (with the phone turned it, the charging took 7 more minutes, to be precise). I also checked, what happens with the current parameters if I started using the phone. That's where the QNOVO kicked in. When I tried using the phone heavily with maximum brightness, etc., the QNOVO - I believe - stepped-up the parameters, so the power being pushed to the phone was still 10 W. It tried to compensate the fact that the phone was in use and it needed some power to work. My conclusion was that no matter if the phone was being used or not, the charging time would basically be the same.
Back to the main topic, why is my QC 2.0 charger supplying the X Compact with only 10 watts of power maximum? I tested it with power bank and a brick. Both are indeed certified by Qualcomm and support QC 3.0. My cables are also compatibile. Am I missing something? I am incredibly curious how does it work. If anyone knows how to help me, please reply 
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