What is reverse wireless charging?

Now you can just charge your phone or headphones from another phone - this is how reverse wireless charging works

While most of us plug in to charge our phones, wireless charging is on the up. It transfers energy to the receiving device via electromagnetic induction. Most often this uses the Qi wireless standard.

So what is reverse wireless charging? The ability to turn the tables; for a wireless charging-capable phone or device to act as the charging station and be used to charge another wireless device. Be that another phone, tablet, or true wireless headphones.

It's a feature that's developed to be more common in flagship devices, first offered by Huawei in the Mate 20 Pro back in 2018, followed by Samsung with the S10 series in 2019. Since then you'll find it in many smartphone brands.

First thing's first: reverse wireless charging isn't as quick as wired. This is a low-power solution that's for emergency top-ups only really - like when your friend has forgotten a cable and is down into 'danger 5 per cent' territory, or for getting some extra juice into those wireless charging headphones. Quick charge technology - i.e., when using a cable - has been progressing over the years and it's not uncommon to find 45W (Samsung), 68W or 120W - and even faster in some cases.

Wireless charging isn't always as quick, but it's advancing too: the Google Pixel 7 will charge at 23W using the Pixel Charger, while Honor has the SuperCharge stand that will charge wireless at up to 100W, if used with a compatible phone, like the Honor Magic 4 Pro - and both these chargers have built-in cooling to make them work.

Reverse wireless charging has to be controlled by the phone, there's not way for efficient external cooling - and if it did charge fast, you'd find that the source device was soon empty. So the reverse wireless charging is often limited to about 5W.

Anything that uses the Qi standard for wireless charging can be charged via reverse wireless charging. That includes many modern smartphones, including the iPhone 14 or Apple AirPods, but also covers the likes of Samsung and Samsung Buds, as well as flagship devices from many brands, like Google Pixel and Pixel Buds.

Many phones are capable of reverse wireless charging, but it often uses a different name. On the Google Pixel it's called Battery Share, on Samsung phones it's called Wireless PowerShare, but it's the same thing - and because it uses the Qi standard, you can charge across brands - the Pixel can charge Samsung headphones, a Samsung phone can charge the Apple iPhone or whatever you want.

In most cases, reverse wireless charging will be turned off, and you'll have to head into the battery settings or the quick settings to toggle it on. It's worth turning off when you're not using it, otherwise any device that can charge wirelessly will charge from your phone when they come into contact.

Although you can charge the iPhone wirelessly using MagSafe or other Qi standard chargers, the iPhone does not offer reverse wireless charging. That means you can't use the iPhone to wirelessly charge your AirPods, for example. Reverse wireless charging has been rumoured as a feature from Apple, but has so far remained absent. You can still charge your Apple devices from other brands, however.