iPhone users in disbelief after discovering unusual charging hack they didn't know existed

A viral post on X (formerly Twitter) has left iPhone owners amazed by pointing out a charging technique that's all new.

The iPhone 15 was a major departure for Apple in some very important ways that weren't necessarily immediately obvious.

While it added some nice new features and made a tiny change to add the Action Button on its Pro models, the iPhone 15's most seismic change was actually around its charging port.

Apple was finally forced by the EU's Digital Markets Act to adopt the USB-C charging port, cutting Lightning out and making sure that people only need one charger for the vast majority of their gadgets.

That port means that loads of accessories, headphones, controllers and more don't need adapters any more, but it has also unlocked a charging hack that only went viral for the first time this past week.

A post from verified X user Sheel Mohnot showed two iPhone 15s connected by a USB-C to USB-C cable, and pointed out in its caption: "PSA: you can charge an iPhone from another iPhone".

This has left users pretty stunned, with one person writing under the post: "Every time you do it you have to thank the EU."

Some others have pointed out that this feature has been around on Android phones for years, too: "Is that new to Apple? I've been able to do this for some time now with my Samsung".

The fact is that this is indeed new to Apple, as we've mentioned before, and it'll only work if one of the phones is an iPhone 15 series phone.

So, you can use an iPhone 15 with a USB-C to Lightning cable to charge an older iPhone, or a USB-C to USB-C one to charge another iPhone 15.

That might leave you wondering how it's decided in which direction the power will flow between two iPhone 15s, and the answer is fairly simple - whichever phone has the lower battery will receive charge from the other.

This tip is super handy since it basically turns your iPhone into a backup power bank if you have a USB-C cable in your bag. This could be amazing for charging headphones or even your laptop in a pinch.

However, it's worth remembering that iPhone batteries don't last forever, so by charging something from your phone you will be draining its battery pretty quickly, making it more of a last resort.

Apple has been phasing out Lightning from its products for around a year now, with only a few devices left before it's completely moved over to USB-C.

Some of the most obvious now are its premium headphones, the AirPods Max, with a new model featuring USB-C charging expected to debut this summer.