How to quickly charge your smartphone: fast charging technologies in detail

The great days are gone when charging a smartphone only required two wires. Today, a charger is a full-fledged computer with more processing power than the Apollo 11 spacecraft that brought humans to the Moon. A processor is necessary in the charger to negotiate charging parameters with the smartphone. Let's dive into fast charging technologies in detail.

The Best Charger – From Your Old Feature Phone

If you plug in your smartphone before bed, unplug it in the morning, and the charge lasts the whole day – you don't need to worry about specific charging standards or chargers.

In such a situation, the best solution is slow charging, for which a low-power charger from your old feature phone is ideal. These devices offer a small power output of 2–5 W, stretching the charging process to 5–7 hours depending on the adapter's power and the battery capacity. This way, your phone's battery charges under the best conditions, minimizing degradation. Fast charging leads to up to 1.6% battery degradation every 100 days, according to an experiment comparing 5W and 25W charging on six identical smartphone batteries.

With a regular charger, your phone will charge in 30 minutes to an hour, and the rest of the time, the battery remains under stress caused by reaching maximum voltage. You can verify this yourself by feeling the battery heating up or by using the Android Battery Temperature app. See battery voltage in real time with Android battery voltage indicator in status bar. An ultra-slow charger will power the phone overnight while keeping the battery temperature at room level.

What Is Considered Fast Charging?

Fast charging is a general term whose technical meaning has changed over time.

Starting with Android 15, Google modified the OS so that Android smartphones display a fast charging notification when the charger delivers at least 20W of power.

Earlier versions of Android consider charging to be fast if it delivers more than 7.5W of power. Charging at 5–7.5W is considered normal, while anything below 5W will display “slow charging.”

What You Need to Know About Fast Charging

If you want to charge your phone quickly, you need to understand the technologies behind it. First, you need to know the power your phone can handle. Charging power is measured in watts. Watts are calculated by multiplying voltage (in volts) by current (in amps).

For example, Google claims that the Pixel 9 can "fast charge" using a 45W Google USB-C charger, but stepping away from this marketing finesse reveals that the phone’s actual maximum charging power is 27W.

You also need to know which charging protocol your smartphone supports. Today, there has been a shift toward standardization, and most phones now support the USB PD protocol. However, many other protocols still exist. It’s important to remember that these protocols are not compatible with each other. If the phone and charger do not support a common protocol, they won’t be able to negotiate fast charging.

Once you know the power and protocol, you can choose a cable and charger capable of delivering the required power. The thing is, USB cables contain ultra-thin wires inside, which are not always made of copper. This significantly reduces the cable’s energy transfer efficiency and causes it to heat up. Some USB cables heat up more than the phone or charger itself.

Keep in mind that the technical specifications of cables, chargers, and smartphones are often exaggerated. Just because a charger says 30W doesn’t mean it can reliably deliver that power over time. At best, it will activate overheat protection and reduce power. At worst, it may fail and even cause a fire.

To use electronics safely, avoid running them at their maximum rated power. For example, if your phone peaks at 30W charging, it’s better to use a charger rated for 45W or more.

The same applies to USB cables. A cable rated for 30W might work well for phone charging but won’t be ideal for a laptop that draws 100W.

Remember that the best USB cables are rated for no more than 5A of current. High-quality USB cables can handle 3A without excessive heating. USB-C to USB-C cables have a special e-marker chip that tells the charger the maximum power the cable can handle. However, keep in mind that the presence of the chip doesn’t guarantee the physical wires are thick enough to safely carry the claimed power.

Fast Wired Charging Technologies

The fastest possible charging is only achievable when a cable is connected to the smartphone. Only wired charging ensures minimal energy loss during the transfer from the charger to the device.

All fast-charging technologies use the same basic principle to deliver high power at the physical level – increasing voltage to reduce current. High current is what melts cables and can potentially cause fires.

However, before the charging adapter starts increasing the voltage, it must first communicate with the smartphone. Incompatibility of the communication software protocol is the reason why a smartphone with USB PD, for example, cannot fast charge from a VOOC charger.

USB PD Fast Charging

USB Power Delivery (USB PD) is the most common charging standard for smartphones, not to mention tablets and laptops.

USB PD is only available via a USB-C connection. USB PD is not supported with a USB-A connector (rectangular plug), unlike some other charging protocols.

USB PD is as close to a universal standard as possible, being supported by almost every modern gadget and charger. Apple, Google, and Samsung use it in all their latest phones and other devices.

While there are different versions of PD, here are just a few key things to know:

• USB PD 1.0 is outdated (since 2020) and supports up to 100W. Its fixed voltages are 5V, 9V, 15V, and 20V with currents of 1.5A, 2A, 3A, and 5A.
• Today, USB PD 2.0 is relevant. It also supports up to 100W of power but does so more flexibly. A USB PD 2.0 charger rated at 36W should support 5V 3A, 9V 3A, and 15V 2.4A. A charger rated at 45–60W adds support for 20V 3A. Chargers rated at 60–100W provide an additional 20V 5A mode.
• USB PD 3.0, now widely adopted, allows for even more flexible voltage negotiation via PPS mode. PPS exists alongside the list of fixed voltages. The max power of USB PD 3.0 is 100W.
• PPS (Programmable Power Supply) support in USB PD 3.0 allows the smartphone and charger to select any voltage within the supported range, in 0.02V steps. For example, instead of fixed 9V, the phone may request 8.7V if its charging controller deems it optimal. These finely tuned voltage levels help precisely control power consumption, minimizing heat while maintaining fast charging. Phones that support PPS require a PPS-compatible charger.
• Extended Power Range (EPR) in PD 3.1 adds 28V, 36V, and 48V options. PD 3.1 enables charging at up to 240W. This power is achieved by increasing voltage to 48V, since USB cables can’t handle more than 5A without melting. At 48V, 240W equals a current of 5A.

Qualcomm Quick Charge (QC) Fast Charging

Qualcomm's Quick Charge (QC) technology was developed to charge batteries faster than standard USB (not USB PD, but fixed 5V 2A). Hardware fast charging is achieved by increasing the output voltage supplied by the charger.

Since many phones use Qualcomm processors, QC support is widespread. There have been several versions of QC, but all the latest three versions (QC 4, 4+, 5) support USB PD and can operate with power up to 100W. QC is also cross-compatible with many other standards.

Starting from QC 3.0, the INOV technology was introduced, which resembles USB PD PPS, allowing the charger and smartphone to adjust the voltage in 0.2V increments.

MediaTek Pump Express Fast Charging

MediaTek is another major chipmaker with its own fast charging technology called Pump Express, which is quite similar to Qualcomm’s QC. It seems that MediaTek is no longer actively promoting this technology, but the Pump Express 4.0, introduced almost a decade ago, is compatible with the USB PD 3.0 standard.

Pump Express 3.0 introduced an interesting solution: direct battery charging. In a typical smartphone, the charger does not actually charge the battery directly — it supplies power to the phone. Charging is handled by the internal charging controller, which steps down the voltage from 5V, 9V, or 12V to a battery-safe level of around 4V. This process generates additional heat in both the phone and the battery.

With Pump Express 3.0, the smartphone disables its internal charging electronics and connects the battery directly to the charger. The charger supplies voltage matching the battery's level — between 3V and 6V — compensating for voltage drop across the USB cable and connectors. Thanks to direct charging, the smartphone heats up significantly less.

VOOC and SuperVOOC Fast Charging

Voltage Open Loop (VOOC) and SuperVOOC protocols remain arguably the most problematic due to the fact that the BBK conglomerate—which owns several well-known smartphone brands including Realme and Oppo—is reluctant to license it to third-party charger manufacturers. This means that owners of Vivo, Oppo, Realme, and other BBK brands get fast charging only when using the original cable and charger included with the phone.

VOOC was first introduced in 2014 and supported 5V/4A, which was nearly twice as fast as the standard USB 5V/2A. Two years later, its successor SuperVOOC was released with a full voltage range.

BBK’s sub-brands received these charging technologies under different names. For example: Flash Charge (also VOOC), Warp Charge (also OnePlus Dash Charge and Realme DART), Super Flash Charge (also SuperVOOC).

SuperVOOC is significantly different from other fast-charging technologies. Firstly, smartphones supporting it feature a dual-cell battery. This dual design helps reduce heat when charging at high currents. Secondly, SuperVOOC moves the charging controller from the smartphone into the charger itself. This reduces heating of the smartphone, though it transfers the heat source to the charger.

With SuperVOOC, separating the battery and moving the controller outside the smartphone is essential, as this technology more than doubles the maximum current compared to the current 5A USB standard:

• SuperVOOC (2016): 10V / 5A = 50W
• SuperVOOC 2.0 (2020): 10V / 6.5A = 65W
• SuperVOOC 2.0 (2022): 11V / 6–7.3A = up to 80W
• SuperVOOC 240W (2022): 20V / 12A = 240W

Mi Turbo Charge and Xiaomi HyperCharge Fast Charging

Another less common charging standard that works only when using the USB cable and charger included with Xiaomi, Poco, or Redmi smartphones.

Mi Turbo Charge is the marketing name for Xiaomi’s early fast-charging technology. It supports up to 33W of power. Xiaomi HyperCharge has since replaced Mi Turbo Charge.

Xiaomi HyperCharge requires an original Xiaomi cable and charger because the USB-A connector used includes an additional physical contact—five pins instead of the usual four.

Although Xiaomi advertises up to 120W in its promotional materials, this figure is only achievable when connected to a 240V power outlet. In Brazil, the USA, Canada, Colombia, Japan, and other countries with 120V power outlets, Xiaomi HyperCharge provides only 96W of power.

Xiaomi HyperCharge supports up to 20V, with current reaching 6A, enabling a maximum power of 120W.

Motorola TurboPower Fast Charging

Earlier Motorola phones used regular fast charging, but their recent models now use TurboPower. Different phone models have different maximum charging speeds, with the fastest TurboPower charger rated for 125W.

Samsung Adaptive Fast Charge (AFC) and Super Fast Charge (SFC)

Samsung Adaptive Fast Charge (AFC) works with 5V for standard charging and 9V for fast charging, supporting up to 2A, which delivers a maximum of 18W. This technology is based on Qualcomm Quick Charge 2.0 and is compatible with most modern Samsung smartphones. It uses USB-A to Micro-USB or USB-C cables and is supported on Exynos and Snapdragon devices.

Samsung Super Fast Charge (SFC) includes two versions. The first, Super Fast Charge 1.0, uses 5V (standard) and 9V (fast) with up to 2.25A, delivering up to 25W. This version uses USB PD 3.0.

The second version, Super Fast Charge 2.0, supports 5V, 9V, 15V, and 20V with a maximum of 2.25A at 20V, and variable current for other voltages—up to 4.05A at 3.3V and up to 2.1A at 21V. This version can deliver up to 45W using USB PD 3.0 with PPS support. It requires a USB-C to USB-C cable rated for 5A.

Huawei Fast Charge Protocol (FCP) and SuperCharge Protocol (SCP)

Fast Charge Protocol (FCP) was introduced in 2015 and uses high voltage with low current for charging. It operates at 9V and 2A, providing up to 18W. FCP was widely used in early Huawei and Honor smartphones.

SuperCharge Protocol (SCP), introduced in 2016, is an advanced version of FCP and supports higher charging power. SCP includes different voltage and current combinations to achieve more power. For example, one SCP configuration is 10V at 4A, which delivers up to 40W. Other variations include 11V at 6A (66W) and 20V at 5A (100W). SCP is used in modern Huawei models like the Mate 20 Pro, Mate 40 Pro, and P60 Pro.

Anker PowerIQ Fast Charging

Fast charging is offered not only by phone and processor manufacturers. Anker, a company that produces power banks and chargers, has its own standard called PowerIQ.

PowerIQ 1.0 delivers a maximum power of 12W by supplying 5V at up to 2.4A. PowerIQ 2.0 is an improved version that includes VoltageBoost technology, which compensates for voltage loss due to cable heating. It still provides 5V at up to 2.4A.

PowerIQ 3.0 is the latest version, supporting up to 100W of power. It is compatible with USB-C Power Delivery (PD) and Qualcomm Quick Charge 3.0. For example, the PowerPort+ Atom III charger with PowerIQ 3.0 features USB-C outputs supporting 5V at 2.4A, 9V at 3A, 15V at 3A, and 20V at 2.25A, as well as a USB-A output providing 5V at 2.4A, 9V at 1.66A, and 12V at 1.25A.

iPhone Fast Charging

Apple provides iPhone users with a fast charging technology called Fast Charge. However, this is just a marketing name—iPhones do not have a proprietary charging protocol like Huawei’s SCP or SuperVOOC. For fast charging, iPhones use the USB PD standard.

Compared to fast charging on Android phones (except Samsung), iPhone’s fast charging looks rather slow:

• The iPhone 16, which supports up to 45W charging, uses up to 15V and 3A current.
• The iPhone 15 and earlier models have a maximum charging power of 29W, with 9V at 3A.
• For models like iPhone 12, iPhone SE (3rd generation), and newer, the recommended charging is 20W (9V / 2.2A).
• For iPhone 8, iPhone X, iPhone XR, iPhone 11, and older, the maximum charging power is 18W, with 9V at 2A.

Fast Wireless Charging Technologies

The most important thing to remember about wireless charging is that it is extremely inefficient. Around 50% of the energy consumed by a wireless charger is lost as heat, which warms up your smartphone. Because of this, wireless charging typically has much lower power output than wired charging.

Wireless charging technology is more accurately described as “USB connector-less charging.” It replaces the USB plug with energy transfer based on electromagnetic induction. In simple terms, a copper coil receives alternating current, generating an alternating magnetic field. A second copper coil placed nearby enters this magnetic field and converts it into alternating electric current. As mentioned earlier, the energy losses are significant.

Here are the main wireless charging standards you might encounter:

Qi Wireless Charging

The Qi wireless charging technology (pronounced “chee”), developed by the Wireless Power Consortium (WPC) in 2010, enables energy transfer over a distance of up to 4 cm between coils. The magnetic field oscillation frequency ranges from 110–205 kHz and adjusts dynamically based on feedback control to regulate charging power.

Qi supports several power profiles. The Baseline Power Profile (BPP) delivers up to 5W of charging power. The Extended Power Profile (EPP) increases this to 15W and is the most common fast-charging option for smartphones. Additionally, there is a Medium Power Profile, offering between 30 and 65W.

• Basic electrical parameters for Qi BPP coils:
  • Voltage at the secondary coil (device side): 5V up to 1A
  • Voltage at the primary coil (charger side): 12V, current approx. 0.5–1A for up to 5W output
• Extended Qi EPP parameters (up to 15W):
  • Voltage at the secondary coil: 9V, current up to 1.67A
  • Voltage at the primary side: 12V or higher, current up to 2A

Apple MagSafe

The Qi standard, like any wireless energy transfer method, has a major issue—precise alignment of the coils. Some manufacturers even printed crosshairs on their devices to help with alignment. But in 2020, Apple introduced a brilliantly simple and effective solution—magnets placed around the outer edge of the coil (as seen in the photo below, with silver rectangles surrounding a yellow copper coil).

Apple essentially took the Qi standard, added a ring of magnets that snap the charger precisely into place, and branded it as MagSafe. MagSafe has been available starting with the iPhone 12 and newer models.

MagSafe initially offered up to 15W of charging power, and with the iPhone 16 and MagSafe 2 (second generation), the power increased to 25W. To achieve maximum charging speed, a power adapter supporting USB Power Delivery (PD) 3.0 with output of 9V / 2.22A or 9V / 2.56A is required.

Qi2 Wireless Charging

Apple’s MagSafe successfully solved the primary issue of wireless charging, and fortunately, Apple shared this design for use in the Qi2 standard, introduced in 2023. Essentially, Qi2 is a marketing name for Apple’s MagSafe adapted for Android smartphones.

Qi2 includes the same magnetic ring as MagSafe. Qi2-compatible devices can charge using MagSafe chargers, and MagSafe-compatible iPhones can charge using Qi2 chargers. However, due to Apple's proprietary certification, only certified MagSafe chargers deliver 15W power. Qi2 chargers, lacking certification, charge iPhones at up to 7.5W.