What is Fast Charging?

Contrary to popular belief, fast charging doesn’t exactly mean quick charging speed. Fast charge is measured by the number of wattage your smartphone battery can deliver — the higher it delivers, the faster it charges. So, batteries that deliver a minimum of 9W are regarded as fast charging. Standard chargers/charging process only deliver 5 Watt (5W).

Fast charging allows for optimized charging in the early stage of charging; meaning, you get an improved battery capacity after a short period of charging. Companies do not boast of a full fast charge because power transfer in the concluding stage of charging drops.

QC 3.0 vs PD 3

QC 3.0
First thing to note is, for Qualcomm Quick Charge (QC) to work, both the smartphone and the charger must be compatible with the same charging voltages and currents. For instance, if your smartphone supports charging at 9V/2A, and you have a 1A charger, then the charging speed will definitely not improve.

The Qualcomm quick charge 3.0 was a massive improvement for the previous versions (1.0, 2.0). It boasts of over 40% increase in speed from the Quick Charge 1.0. However, the most interesting feature of the Quick Charge 3.0 is its INOV (Intelligent Negotiation for Optimum Voltage) feature.

This feature was designed with, not just charging speed, but charging efficiency in mind. It allows for monitored power output. This is because different smartphone batteries come with different charge voltage.

For instance, the previous version (Quick Charge 2.0) supports 4 modes with different power levels – 5 V/2A, 9V/2A, 12V/1.67A, and 20V option. The quick charge 3.0, on the other hand, was designed to use the INOV feature to communicate with the device to find out the voltage required.

This feature helps to reduce the amount of energy that’ll go to waste during charging. While charging your device, you might notice it heating up, this is the energy that goes to waste, and it can reduce your battery life span. The INOV feature ensures that lesser energy is lost, which means less heat.

PD 3.0
It was developed by the USB implementers Forum (USB-IF). It works a little bit differently from Qualcomm’s Quick Charge but they both try to achieve the same result — faster charge. Power Delivery was designed to allow any smartphones to fast charge over a USB connection cable.

It is capable of delivering up to 100W – even though smartphones don’t need up to that to fast charge. It is useful for other devices though, including laptops with USB-C port.

Apple, for instance, uses the USB- PD fast charge for its iPhone XS, iPhone XS Max, iPhone X, iPhone 8, and iPhone 8 Plus.

The power delivery 3.0 came with a few improvements from the previous 2.0 version. It offers a wide range of rules in four categories —7.5Wattage, 15W, 27W, and 45W— each with a range of voltage. For instance, sources supplying 27W will offer 5, 9, and 15 volts. Power delivery 3.0 could reach a supply of 100W with 20V.

Which should you choose?
why have to choose, our power banks are equipped with both QC and PD.

Quick Charge is a technology featured in Qualcomm Snapdragon SoCs, used in devices such as mobile phones, for managing power delivered over USB, mainly by communicating to the power supply and negotiating a voltage.

It increases the voltage and thus charges batteries in devices faster than standard USB rates allow. Quick Charge 2 onwards technology is primarily used for wall adaptors, but it is also implemented in in-car chargers and powerbanks (for both input and output power delivery).

Quick Charge is also the basis of other proprietary rapid-charging systems developed by other manufacturers.

Quick Charge is a proprietary technology which allows for the charging of battery powered devices, primarily mobile phones, at levels above and beyond the typical 5 volts and 2 amps for which most USB standards allow. Numerous other companies have their own competing technologies; these include MediaTek Pump Express and OPPO VOOC (licensed to OnePlus as “Dash Charge”).

Despite being proprietary, the exact behavioural patterns (e.g. voltage negotiations between device and charger) have already been reverse-engineered.

To take advantage of Qualcomm Quick Charge, both the host providing power and the device must support it. In 2012 the USB Implementers Forum (USB IF) announced that their USB Power Delivery (USB PD) standard had been finalized which allows for devices to transfer up to 100 watts of power over capable USB ports. This new technology was first seen in a Xiaomi Mi Mix 3 prototype that went from 1% to 100% in a mere 17 minutes.

Quick Charge 2.0 introduced an optional feature called Dual Charge (initially called Parallel Charging).[5] Dual Charge utilises two PMICs to split the power into 2 streams to reduce phone temperature.

Quick Charge 3.0 introduced INOV (Intelligent Negotiation for Optimal Voltage) and Battery Saver Technologies. INOV is an algorithm that determines the optimum power transfer while maximizing efficiency. Battery Saver Technologies aims to maintain at least 80% of its original charge capacity after 500 charge cycles.[7] As well as HVDCP+ and Dual Charge+ (optional). Qualcomm claims Quick Charge 3.0 is up to 4-6C cooler, 16% faster and 38% more efficient than Quick Charge 2.0. And that Quick Charge 3.0 with Dual Charge+ is up to 7-8C cooler, 27% faster and 45% more efficient than Quick Charge 2.0 with Dual Charge.

Quick Charge version 4 was announced in December 2016 alongside the Snapdragon 835. Quick Charge 4 includes HVDCP++, Dual Charge++ (optional), INOV 3.0 and Battery Saver Technologies 2. Version 4 is compatible with both USB⁠-⁠C and USB Power Delivery (USB-PD) specifications. Thus Quick Charge 4 falls back onto USB-PD if either the charger or device is not compatible. Version 4 also features additional safety measures to protect against over-voltage, over-current and overheating, as well as cable quality detection. Qualcomm claims Quick Charge 4 with Dual Charge++ is up to 5C cooler, 20% faster and 30% more efficient than Quick Charge 3.0 with Dual Charge+.

Quick Charge 4+ was announced on June 1, 2017. Quick Charge 4+ introduces Intelligent Thermal Balancing and Advanced Safety Features to eliminate hot spots and protect against overheating and short-circuit or damage of the USB-C connector. And Dual Charge++ is required, in prior versions Dual Charge was optional.