Wireless Reverse Charging

Introduction

Technology has evolved rapidly over the past few decades, changing the way we live, work, and communicate. Among the most significant advancements is in the field of wireless technology, which has expanded into various aspects of our lives—from wireless communication to wireless charging. One of the latest and most innovative features in mobile technology is Wireless Reverse Charging. This feature, while relatively new, is rapidly gaining traction in smartphones, wearables, and other smart devices.

This article will explore wireless reverse charging in depth, including its working principle, advantages, challenges, and the future of this exciting technology.

Install App

What is Wireless Reverse Charging?

Wireless Reverse Charging, also known as reverse wireless charging or power sharing, is a feature that allows a device (typically a smartphone) to wirelessly transfer power to another compatible device. In other words, your smartphone can act as a wireless charging pad for another phone, wireless earbuds, smartwatches, or any device that supports Qi wireless charging.

Instead of using a traditional cable or a wireless charging dock, the source device generates an electromagnetic field using its built-in coil. The receiving device, when placed close to the source, receives this energy and converts it into electrical power to charge its battery.

History and Evolution

Wireless reverse charging builds upon the foundation of wireless charging, which became mainstream in the 2010s. The first notable commercial implementation of wireless charging was seen in devices using the Qi (pronounced “chee”) standard, developed by the Wireless Power Consortium (WPC).

Samsung was one of the pioneers in wireless charging adoption, followed by other major manufacturers like Apple, Huawei, and Google. Huawei took a step further by introducing reverse wireless charging in its Mate 20 Pro in 2018, allowing users to charge other devices from the smartphone itself.

How Does It Work?

Wireless reverse charging is based on the same principle as wireless charging: electromagnetic induction.

Basic Principles of Electromagnetic Induction

Transmitter Coil: The device that sends power has a coil that generates an alternating electromagnetic field.
Receiver Coil: The device receiving the power has a corresponding coil that picks up the field.
Energy Conversion: The magnetic energy is converted back into electrical energy, which charges the battery.

Reverse Wireless Charging Process

The source device (smartphone) is set to reverse wireless charging mode.
The receiving device (e.g., a smartwatch or phone) is placed back-to-back with the source.
The source emits an electromagnetic field.
The receiver captures the field using its internal coil.
Power is transferred, and the device begins to charge.

Standards Involved

Most devices use the Qi wireless charging standard, which ensures compatibility across devices from different manufacturers. For reverse charging, the power output is often limited to around 2.5W to 10W, depending on the manufacturer and hardware.

Devices that Support Wireless Reverse Charging

Some flagship smartphones that support reverse wireless charging include:

Huawei Mate 20 Pro, P30 Pro, Mate 40 Pro
Samsung Galaxy S10 series, S20 series, Note 10, Note 20, Galaxy Z Fold/Flip series
Google Pixel 5, Pixel 6, Pixel 7
Apple iPhone 11 and newer (limited and mostly used to charge accessories like the Apple Watch or AirPods)

Other devices such as wireless earbuds (e.g., Galaxy Buds, AirPods Pro) and smartwatches (e.g., Galaxy Watch, Huawei Watch) can be charged via reverse wireless charging when placed on the back of a compatible smartphone.

Advantages of Wireless Reverse Charging

1. Convenience

It eliminates the need for cables and chargers, especially useful when you are on the go and need a quick top-up for your accessories.

2. Emergency Power Sharing

Imagine you’re traveling with a friend whose phone is dying. With reverse wireless charging, your phone can give theirs a much-needed power boost.

3. Multi-Device Ecosystem Integration

For users of smart ecosystems (like Samsung Galaxy or Apple devices), this feature allows seamless charging of accessories like earbuds and watches directly from the smartphone.

4. Reduces Gadget Dependency

Carrying fewer chargers and cables is always a plus, especially during travel. This feature helps reduce clutter and dependency on multiple charging accessories.

Limitations and Challenges

Despite its innovative appeal, wireless reverse charging has some limitations:

1. Slow Charging Speeds

Reverse wireless charging is significantly slower than wired charging. For example, while wired charging may deliver 25W or more, reverse wireless typically caps at 5W-10W.

2. Energy Efficiency

Wireless energy transfer is not as efficient as wired charging. Energy is lost in the form of heat, and it takes longer to charge a device.

3. Battery Drain on the Host Device

Using your smartphone to charge other devices can significantly deplete its battery, which could be a problem if you are also running low.

4. Heating Issues

Transferring energy wirelessly generates heat, which may lead to thermal throttling or discomfort during use.

5. Limited Compatibility

Only devices that support Qi charging can benefit from this feature. Older devices or those with proprietary charging methods won’t work.

How to Use Wireless Reverse Charging

Each brand has a different way to enable this feature. Here’s a general guide:

Samsung Galaxy Devices

Go to Settings > Battery and device care > Battery.
Select Wireless PowerShare.
Turn it on.
Place the other device on the back of your phone.

Huawei Devices

Navigate to Settings > Battery > Reverse Wireless Charging.
Toggle the feature on.
Align the other device on the back of your phone.

Google Pixel Devices

Reverse wireless charging is automatically enabled when the phone is plugged in.
To charge wirelessly when the phone is not plugged in, users may need to turn on Battery Share under settings.

Use Cases and Scenarios

1. Charging Earbuds on the Go

Wireless earbuds often have small batteries. Reverse charging allows you to recharge them without needing their charging case or a separate power source.

2. Smartwatch Top-Up

Out for a run and your smartwatch dies? Simply place it on your phone for a few minutes to restore functionality.

3. Peer-to-Peer Charging

Two people with compatible devices can share power—especially useful in emergencies or while traveling.

4. Marketing and Differentiation

Manufacturers use this feature to differentiate their devices in a crowded market. It’s also a conversation starter and shows innovation.

Technological Considerations

To achieve efficient reverse wireless charging, manufacturers must design:

High-performance coils that are thin enough to fit into sleek smartphones.
Thermal management systems to prevent overheating.
Smart battery management software to control when and how much power is shared.
Magnetic alignment systems to ensure proper placement between devices.

The Future of Wireless Reverse Charging

As the technology matures, we can expect:

1. Increased Efficiency

New materials and improved coil design could enhance the efficiency of energy transfer.

2. Higher Power Output

Future devices may support 15W or more of reverse wireless charging, enabling faster charging times.

3. Wider Adoption

More mid-range and budget devices may include this feature as components become cheaper.

4. Cross-Device Charging

We may soon see laptops wirelessly charging phones or tablets wirelessly powering IoT devices.

5. Smart Power Allocation

AI-powered software could intelligently distribute power based on battery status, temperature, and user habits.

Conclusion

Wireless reverse charging represents a significant step toward a wire-free future. While it’s currently more of a convenience than a necessity, its potential applications are broad and exciting. As the technology becomes more efficient, powerful, and widely adopted, it may become a standard feature on all mobile devices.

Though it has its limitations—like slow speed, heating issues, and efficiency concerns—wireless reverse charging provides a glimpse into the future of personal technology, where devices are more connected and capable than ever before.