Reverse Wireless Charging: How It Works & Is It Worth It?

Reverse wireless charging lets a phone or tablet act as a wireless charging pad to top up other Qi-compatible devices, like earbuds, smartwatches, or another phone. It is a genuinely incredible convenience for on-the-go power sharing, but it has real limitations in speed and efficiency that make it a backup feature rather than a primary charging method.

What Is Reverse Wireless Charging?

Reverse wireless charging (also called bilateral or two-way wireless charging) is a feature found on many flagship smartphones since around 2019. It uses the same Qi inductive charging standard as a standard wireless pad, but reverses the power flow: instead of receiving power, the phone’s internal coil transmits it to another device placed on its back.

There are two flavors:

• Reverse wireless charging – charges earbuds, smartwatches, and other phones at low speeds (typically 2.5W–5W).
• Reverse wireless charging with higher output – some phones can deliver up to 10W or even 15W, which can charge another phone at a usable (but still slower than wired) rate.

Most phones with this feature include a toggle in the battery or connections settings, and many automatically disable it when the phone’s battery drops below a certain percentage (often 20–30%) to preserve the host phone’s charge.

How Does It Work?

Wireless charging uses electromagnetic induction. Inside the phone is a copper coil. When you place a device on a Qi pad, the pad’s coil creates an alternating magnetic field, which induces a current in the device’s coil, charging its battery.

In reverse wireless charging, the phone’s coil does the opposite: it draws power from the phone’s battery and generates its own alternating magnetic field. The receiving device (like an earbud case) has its own coil that picks up that field and converts it back into electrical current. The two devices must be aligned properly, and they communicate over the Qi protocol to negotiate power delivery and ensure safe operation.

The key components are:

• Transmitting coil – the phone’s internal coil, which is the same coil used for receiving power.
• Power management IC – regulates voltage and current, and handles the direction of power flow.
• Qi communication – a low-level data signal that tells the receiver how much power to expect and when to stop.

What Can You Charge With It?

The most common uses are:

• True wireless earbuds – most TWS cases (like AirPods or Samsung Galaxy Buds) are Qi-compatible, so you can top them up by placing the case on the back of your phone.
• Smartwatches – many smartwatches (including Apple Watch and Samsung Galaxy Watch) support Qi charging, but some require specific alignment, so it may not work perfectly with every phone.
• Another phone – you can charge a friend’s phone in an emergency, but it’s slow and drains your battery quickly.
• Other small Qi devices – some wireless mice, styluses, or even electric toothbrushes use Qi, though compatibility varies.

It will not work with devices that use proprietary wireless charging (like some older smartwatches) or with devices that don’t have a Qi receiver at all.

Pros and Cons

Advantages:

• Convenience – no need to carry a separate power bank or cable for your earbuds.
• Emergency sharing – you can give a friend a few percent of charge when they’re out of battery.
• Less clutter – one device can serve as a backup charger.

Disadvantages:

• Slow – typical reverse charging speeds are 2.5W–5W, which is much slower than a wired charger (usually 15W–65W).
• Inefficient – wireless charging is inherently less efficient than wired; you lose a significant amount of energy as heat.
• Drains your battery – charging another device consumes your phone’s battery, so you’ll need to plug in your phone sooner.
• Heat – both devices get warm, which can affect battery health over time.

How to Use It (Step-by-Step)

Using reverse wireless charging is straightforward, but the exact steps vary by phone. Here’s the general process:

1. Enable the feature – Go to Settings → Battery → Wireless Power Sharing (or similar). Some phones have a quick toggle in the notification shade.
2. Place the device – Put the device you want to charge (e.g., earbud case) on the back of your phone, centered near the middle. You may need to remove a thick case.
3. Wait for the connection – Your phone will usually vibrate or show a notification that charging has started.
4. Monitor the charge – The receiving device will show its own charging indicator. Keep the devices still to maintain alignment.
5. Disconnect when done – Remove the device or disable the feature to stop power transfer.

If you’re charging another phone, make sure that phone’s wireless charging is enabled (it usually is by default). Some phones require you to turn on “Wireless Power Sharing” in the receiving phone’s settings if it has the option.

Common Problems and Misconceptions

“It charges as fast as a normal wireless pad.” False. Reverse wireless charging is deliberately limited to low power (2.5W–5W) to prevent overheating and excessive battery drain. It’s meant for topping up small devices, not for a full charge.

“It works with any Qi device.” Not always. Some devices use proprietary charging protocols (like Apple Watch’s older magnetic charger) or have alignment requirements that don’t match a phone’s coil position. Check compatibility before relying on it.

“It damages your phone battery.” Using it occasionally is fine, but frequent use generates extra heat, which can degrade battery health over time. Most phones have safeguards to stop charging if the temperature gets too high.

“You can charge your phone and another device at the same time.” No. The phone cannot receive and transmit power simultaneously through the same coil. You must unplug your phone to use reverse wireless charging.

“It works through thick cases.” Some thin cases (under 3mm) may work, but thick or metal cases will block the signal. Remove the case if charging fails.

Is It Worth It?

Reverse wireless charging is a “nice to have” rather than a must-have. It’s incredibly handy when you’re out and your earbuds die, or when a friend’s phone is at 1% and you want to give them a few minutes of talk time. But it’s not a replacement for a power bank or a wired charger for your main phone.

If you already own a flagship phone that supports it, you’ll likely use it occasionally. If you’re deciding between two phones and one has reverse wireless charging, it’s a small bonus, but don’t make it the deciding factor unless you frequently find yourself in emergency charging situations.

Frequently Asked Questions

Can I use reverse wireless charging to charge my phone from another phone? Yes, if both phones support reverse wireless charging and have Qi receivers. However, the charging speed will be very slow (around 2.5W–5W), so it’s only useful for emergency top-ups, not a full charge.

Does reverse wireless charging work with iPhone? iPhones have supported reverse wireless charging for accessories since the iPhone 12, but only for MagSafe-compatible accessories like AirPods. Apple has not enabled reverse charging for other phones as of this writing.

Why is my reverse wireless charging not working? Check that both devices are Qi-compatible, the feature is enabled, the receiving device is placed correctly (usually centered), and there’s no thick case or metal object between them. Also, ensure your phone has enough battery (above the threshold set by the manufacturer).

Does reverse wireless charging work while the phone is plugged in? No. The phone cannot charge itself and transmit power at the same time through the same coil. You must unplug the phone to use reverse wireless charging.

Is reverse wireless charging safe for my earbuds? Yes, it’s safe as long as the earbuds are Qi-compatible and the charging process doesn’t overheat them. If your earbuds get excessively hot, stop charging and let them cool down.

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