MSP Explained: Fast Charging on Smartphones, How Does it Work, and More 

Recently, Realme made it to the headlines, thanks to its 300W fast charging capabilities. While it’s still a thing of the future, 120W or 100W fast charging capabilities are not unattainable anymore. There are several smartphones out there that juice up your device in about half an hour, thanks to this crazy fast charging technology. And if you wonder how it works, the standards involved, and more — you are in the right place. In this week’s MSP Explained, we’re diving into exactly that. Let’s get started!

Basic Charging Terms

Before we get into the details of fast charging technology, let’s first cover some basic terms related to smartphone charging, such as Watt, Voltage, and others.

• Watt (W): A unit of power that measures how fast energy is used or transferred. In charging, higher watts mean faster charging.
• Voltage (V): The pressure that pushes electric current through the charging cable into your phone.
• Power: The rate at which energy is transferred to your phone. It’s calculated by multiplying voltage (V) and current (A).
• Current (A or Amps): The amount of electricity flowing through the cable to charge the battery.

How Does Fast Charging Work on a Smartphone?

At its core, fast charging increases the power delivered to a smartphone’s battery. A standard USB port typically provides around 2.5 to 5 watts, which can be painfully slow for modern devices. Fast charging technologies can deliver anywhere from 18W to over 240W, significantly reducing charging times.

The charging process has two main phases. The first is the Constant Current Phase, where a high current is delivered to the battery for faster charging. This phase works best when the battery is below 50%.

You’ve likely noticed that when your phone’s battery is around 10%, it charges quickly. But once it passes 50%, the charging speed slows down. This is due to the the second phase called as the Constant Voltage Phase. As the battery reaches its maximum voltage, the current decreases to prevent overheating and potential damage.

However, now the question that might arise in anyone’s mind is while all of this is okay on paper. But how do smartphone companies achieve fast charging without compromising the battery’s health? Well, the companies use several techniques:

• Higher Voltage: Fast chargers increase the voltage sent to the battery. For example, while a standard charger might use 5 volts (V), fast chargers can use 9V, 12V, or even higher. This higher voltage allows more power to flow into the battery at a faster rate.
• Increased Current: Alongside higher voltage, fast chargers can also boost the current (measured in amps) delivered to the battery. For instance, instead of 1 ampere (A), a fast charger might deliver 2A or more. More current means more power being transferred to the battery.
• Advanced Charging Protocols: Fast charging protocols, such as Qualcomm’s Quick Charge or USB Power Delivery, are designed to manage how power is delivered safely. These protocols allow the phone and charger to communicate and adjust the power flow based on the battery’s needs and temperature.
• Battery Design: Modern smartphones often use advanced battery technologies, such as dual-cell batteries, which can handle higher charging speeds. Dual-cell batteries split the power load between two cells, improving charging efficiency and reducing heat.
• Thermal Management: To prevent overheating, fast chargers and phones incorporate cooling mechanisms and thermal management systems. This includes heat dissipation technologies and smart algorithms that regulate the charging speed based on temperature.

By combining these techniques, companies can reduce charging times while maintaining safety and battery health.

Smartphone Fast Charging Standards

Smartphone brands continue to introduce more fast charging solutions and different standards have emerged across manufacturers. Some of the most common ones include:

• USB Power Delivery (USB PD): This is the official fast charging standard that can deliver up to 100W, making it suitable for smartphones and laptops. It is widely adopted across various brands, including Apple and Google.
• Qualcomm Quick Charge: This technology, primarily used in devices with Snapdragon processors, offers several versions, with Quick Charge 5 supporting over 100 watts. It is known for its ability to charge devices rapidly, often achieving 50% in just 15 minutes.
• VOOC and SuperVOOC: Developed by OPPO, these standards can deliver up to 80 watts, allowing for extremely fast charging times, often achieving a full charge in under 30 minutes. The same VOOC charging technology is also used by other brands like OnePlus and Realme in their premium devices.
• Samsung Adaptive Fast Charging: This technology is based on Quick Charge and can deliver up to 45 watts, enabling rapid charging for compatible Samsung devices.
• Xiaomi’s HyperCharge: Xiaomi’s HyperCharge technology can charge your phone super-fast. For example, it can fully charge a 4,000mAh battery in just 15 minutes! This is possible because it uses a special battery design and advanced charging methods.

What’s Wireless Fast Charging and How Does it Work?

There’s also wireless fast charging, which many phones now support. When wireless charging technology arrived, it only supported slow charging, which was tedious. But today, some smartphones support up to 80W of wireless charging, which goes from 0 to 100% in about an hour.

The wireless charging technology uses electromagnetic induction, where a charging pad generates an electromagnetic field that transfers energy to a receiver coil within the smartphone.

Imagine you have a smartphone and a wireless charging pad. Both of these devices contain coils of wire. When you place your smartphone on the charging pad, the pad generates an electromagnetic field by sending an electric current through its coil. This electromagnetic field then induces a current in the coil inside your smartphone.

Fast Charging vs Wireless Charging

Smartphones with Fastest Charging Support

Note: These results aren’t based on company claims or third-party sources. Our Core Testing Team (CTT) conducted battery tests on over 20 smartphones, and from those, we’ve selected the top 5 performers that reached 100% charge in under 40 minutes.

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Conclusion

So, that sums up pretty much everything about fast-charging technology on smartphones. It all started with about 2.5W to 5W of charging support, and today, we have 80,120W of fast charging support in our consumer-grade devices. And the brands are already testing a whopping 300W fast charging capabilities.

While fast charging offers significant convenience, it’s not without its drawbacks. Some experts argue that extremely rapid charging can accelerate battery degradation over time. However, manufacturers claim that advancements in battery materials and intelligent algorithms have mitigated these concerns.

Ultimately, the debate over whether fast charging harms battery life is complex, and best left to researchers. For now, we have incredibly powerful chargers that can fully charge your device in no time. So, if you’re always on the move, fast charging should be on your list when considering your next smartphone purchase.