What is Reverse Wireless Charging?
Reverse wireless charging is a feature that allows a smartphone to function as a wireless charger by using the same Qi coil that normally receives power to instead transmit power to another device. In standard wireless charging, the phone is the receiver; with reverse wireless charging, the phone becomes the sender. This lets you charge compatible accessories like wireless earbuds, smartwatches, and even other smartphones simply by placing them on the back of your phone. It is a convenient emergency charging option when you are away from a wall outlet or cable, and it has become a standard feature on most flagship smartphones from Samsung, Google, Huawei, and other manufacturers.
In-Depth
How Reverse Wireless Charging Works
Standard Qi charging uses a coil in the charging pad to generate a magnetic field that induces current in a receiving coil inside the phone. Reverse wireless charging flips this relationship: the phone’s internal coil switches from receiver mode to transmitter mode, drawing power from the phone’s own battery and generating a magnetic field from its back surface. Any Qi-compatible device placed on the phone’s back will pick up that magnetic field and charge. The phone’s firmware manages the power flow, monitoring temperatures and battery levels to ensure safe operation.
Brand Names and Specifications
Different manufacturers market reverse wireless charging under various names.
| Manufacturer | Feature Name | Output | Example Devices |
|---|---|---|---|
| Samsung | Wireless PowerShare | 4.5-5 W | Galaxy S and Z series |
| Apple | MagSafe (iPhone to AirPods) | 5 W | Recent iPhones (limited) |
| Battery Share | 5 W | Pixel series | |
| Huawei | Wireless Reverse Charging | 5-10 W | Mate series |
| Xiaomi | Reverse Charging | 10 W | Flagship models |
The primary use case is charging small accessories like wireless earbuds cases (roughly 300-600 mAh) and smartwatches. Charging another smartphone is technically possible but very slow at 5 watts and drains the host phone’s battery quickly, so it should be reserved for genuine emergencies.
Benefits and Limitations
The greatest benefit of reverse wireless charging is convenience: you can top up your earbuds or smartwatch without carrying a separate charger or cable. For a phone with a battery capacity of 5,000 mAh or more, charging a small earbuds case is barely noticeable in terms of battery drain. However, wireless power transfer is inherently less efficient than wired charging, so some energy is lost as heat during the transfer. Always ensure your phone has sufficient remaining charge before enabling the feature to avoid draining your phone when you need it most.
How to Choose
1. Confirm Qi Compatibility of Your Accessories
Reverse wireless charging only works with Qi-compatible devices. Before relying on this feature, verify that your wireless earbuds, smartwatch, or other accessories support Qi wireless charging. Devices that use proprietary non-Qi charging pucks will not work.
2. Prioritize Phones with Large Batteries
If you plan to use reverse wireless charging regularly, choose a smartphone with a battery of 5,000 mAh or more. Larger batteries absorb the energy cost of charging accessories without significantly impacting your phone’s daily battery life.
3. Compare Output Wattage
Higher output means faster charging. The standard 5-watt output takes roughly an hour to charge a typical earbuds case. Some Huawei and Xiaomi phones offer 10-watt reverse charging, cutting that time nearly in half. If this feature is important to you, look for phones with higher reverse charging output.
The Bottom Line
Reverse wireless charging is a thoughtful feature that turns your smartphone into an emergency charger for Qi-compatible accessories. It is most useful for topping up earbuds and smartwatches on the go, and it works best on phones with large batteries and higher output wattages. While it is not a replacement for a dedicated charger, it eliminates the need to carry extra cables for small accessories and provides a helpful safety net when outlets are nowhere to be found.