Reverse Charging: Turn Phone Into Power Bank?

Yes, you can turn your phone into a power bank using reverse wireless charging or reverse wired charging, provided your phone supports the feature. You simply enable the option in settings and place another device on the back of your phone (or connect it via cable) to share your battery. This guide explains how it works, which phones support it, and what to watch out for.

What Is Reverse Charging?

Reverse charging lets a smartphone act as a power source to charge another device. There are two main types:

• Reverse wireless charging – also called “Wireless PowerShare” or “Battery Share.” Your phone’s built-in wireless charging coil reverses its role and outputs power to charge another Qi-compatible device placed on its back.
• Reverse wired charging – sometimes called “OTG (On-The-Go) reverse charging.” Your phone outputs power through its USB-C (or occasionally Micro-USB) port to charge another phone or accessory via a cable.

Most modern flagship phones from Samsung, Huawei, Xiaomi, and Google support reverse wireless charging. Reverse wired charging is more common across mid-range and budget phones, often labeled as “OTG” in settings.

How Reverse Wireless Charging Works

Wireless charging uses electromagnetic induction. A coil in the charger creates an alternating magnetic field, which induces a current in a coil inside the device being charged. In reverse wireless charging, your phone’s coil does the opposite: it draws power from your battery and drives the coil to create that magnetic field, transferring energy to the other device’s coil.

Because the coils must be closely aligned, you need to place the receiving device directly on the back of your phone, usually centered. Cases thicker than about 3 mm (0.12 inches) or metal cases can block the field, so you may need to remove them. The charging speed is typically limited to 4.5W–10W, which is slower than a wall charger but useful for topping up earbuds, smartwatches, or another phone in an emergency.

How to Use Reverse Charging

Here’s a general step-by-step guide for most phones:

1. Open Settings and search for “reverse charging” or “battery share.”
2. Enable the toggle. Some phones require you to keep the screen on or have the phone plugged in.
3. For wireless: place the device you want to charge face-down or back-down on the center of your phone’s back. You’ll usually see a vibration or a charging icon when it connects.
4. For wired: connect a USB-C to USB-C (or USB-C to Lightning) cable between your phone and the other device. Your phone will act as the power source.
5. Stop charging by removing the device or disabling the toggle.

Note: On many phones, reverse wireless charging automatically turns off if the phone’s battery drops below 30% to preserve enough power for the phone itself.

Which Phones Support It?

Reverse wireless charging is a premium feature, found on:

• Samsung Galaxy S10 and later (except FE models until S21 FE)
• Huawei Mate 20 Pro and later, P30 Pro and later
• Xiaomi Mi 9 and later, and many Redmi/POCO models with “reverse charging”
• Google Pixel 5 and later (Pixel 5–8 series)
• iPhone 12 and later (called “Battery Sharing” but only works with MagSafe accessories, not other phones)

Reverse wired charging is more widespread. Many mid-range phones support it via OTG, but the feature may be hidden under “OTG” in settings or require a special cable. Check your phone’s manual or search online for your specific model.

Common Problems and Limitations

Reverse charging has several limitations you should know about:

• Slow speed: Wireless reverse charging typically delivers only 4.5W–10W, so charging a phone from 0% could take several hours. It’s best for small accessories or emergency top-ups.
• Heat: Both phones get warm during charging. Excessive heat can degrade battery health over time.
• Battery drain: Your phone’s battery will drop quickly. Charging another phone from 50% to full might drain your phone completely.
• Alignment: Wireless charging requires precise alignment. Moving the device can interrupt charging.
• Case interference: Thick or metal cases block the signal. Remove them for reliable charging.

Safety and Battery Health

Using reverse charging occasionally is safe, but frequent use can shorten your battery’s lifespan. Lithium-ion batteries degrade faster with heat and deep discharges. To minimize risk:

• Don’t use reverse charging while your phone is also charging (unless the phone explicitly supports it).
• Stop if the phone gets uncomfortably hot.
• Keep the receiving device aligned and remove thick cases.
• Use it as an emergency feature, not a daily habit.

Also, reverse charging will not work if the phone is off or in some power-saving modes. Some phones require the screen to be on, which adds to battery drain.

Alternatives to Reverse Charging

If your phone doesn’t support reverse charging, or you need faster charging, consider:

• Portable power bank: A dedicated power bank offers higher capacity and faster charging speeds.
• USB-C to USB-C cable: Some phones support “dual-direction” charging over USB-C, but this is rare. Check your phone’s specifications.
• Charging adapter: Carry a wall charger and cable for the fastest top-up.

Frequently Asked Questions

Can I charge my iPhone with reverse wireless charging from a Samsung?
Yes, iPhones support Qi wireless charging, so they can be charged by a Samsung phone with reverse wireless charging. However, the iPhone will only charge at 7.5W max, and the Samsung’s output is limited too, so it will be slow.

Does reverse charging work with any phone?
No. Both the sending and receiving devices must support the required standard. For wireless, the receiving device must support Qi wireless charging. For wired, the receiving device must accept power over USB-C (or Lightning with an adapter).

Will reverse charging damage my phone’s battery?
Occasional use is safe, but frequent use generates heat and drains the battery, which can accelerate degradation. It’s best to use it sparingly and avoid letting your phone drop below 20% while reverse charging.

Why is my reverse charging so slow?
Reverse wireless charging is intentionally limited to low wattage (4.5W–10W) to manage heat and battery stress. Also, the receiving device may limit its own charging speed. Expect slower speeds than a wall charger.

Can I reverse charge my smartwatch or earbuds?
Yes, that’s the most common use. Most modern smartwatches and wireless earbuds cases support Qi charging, so they can be charged by placing them on the back of your phone.

Does reverse charging work if my phone is plugged in?
Some phones allow it, but many disable reverse wireless charging while plugged in to prevent overheating. Check your phone’s behavior. Reverse wired charging via OTG often requires the phone to be unplugged.

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