My answer to What is the difference of Qualcomm Quick Charge 3.0 vs 2.0 vs 1.0 solution?
Answer by Allen He:
So here in this passage, we will make a comparison in Quick Charge 3.0, 2.0 and 1.0 to see what the improvement is and how they do benefit our charging experience.
Perhaps the best way to get to know this question is to compare the charging values between each of Qualcom’s Quick Charge revisions.
Quick Charge 3.0
Quick Charge 2.0
Here we can see that the amount of current offered by Quick Charge has remained relatively consistent, but increasing the charging voltage has helped allow for faster charge times. With 3.0, the range of voltages will allow for fast charging and better efficiency.
For smartphones, the actual maximum amount of power available has not really changed from Quick Charge 2.0’s 18W maximum. Newer 9V models will still take the same 18W peak power as before, although lower voltage batteries may receive a power boost, allowing them to charge up a little faster than before. But this all depends on the exact hardware.
Importantly, Qualcomm has retained backwards compatibility with its 2.0 and 1.0 standards. As the power draw is handled on the smartphone side, you will safely receive the maximum amount of power for your device using any of the certified chargers. However, you won’t achieve full charging speeds if you try charging newer phones with older lower power chargers.
Although Qualcomm supports Quick Charge in all of its new SoCs, it is still up to smartphone and tablet manufacturers to implement the specific circuitry required to make full use of the fastest charging speeds available. Keep an eye out for Quick Charge 3.0 devices.