In a pinch, your iPhone 15 can recharge your Apple Watch or AirPods, and even juice up another iPhone It’s a new feature that’s very convenient if you know how to use it.
Here’s how to take advantage of this feature.
Another use for your iPhone 15 battery
If there are no electrical sockets nearby and your AirPods or Apple Watch are running low on power, you can use your iPhone 15 to give them a boost. The same goes for another iPhone. All you need for most of these devices is a compatible cable.
It’s a new capability of the 2023 models so don’t try it with an earlier one. You can thank the USB-C port in the latest iOS handsets for this trick.
Powering up AirPods or Apple Watch
Your AirPods are almost out of juice and you can’t take an afternoon without music? No problem. As our tests prove, connect the earbuds’ case to your iPhone and power starts flowing immediately.
You do need a cable for this trick, though. Rolling Square inCharge X ($29) is a great option. It’s very, very portable, and works whether your AirPods case uses USB-C or Lightning.
Or if you forget to recharge your Apple Watch, you can use your iPhone to do the job. This is a bit more complicated because Apple’s wearable requires a wireless charger, not just a cable. We did our testing with a Pitaka Power Dongle for Apple Watch ($59.99), which is small enough to go anywhere.
How to charge an iPhone with an iPhone 15
Photo: Ed Hardy/Cult of Mac
Suppose your iPhone has a 100% charge but the one belonging to your friend/spouse/child is down at 3%. You can be generous and transfer some of the power from your device to theirs.
Again, to get power from one iPhone to another, you’re going to need a cable. This isn’t an example of reverse wireless charging. This is another reason why you might want to carry around a Rolling Square inCharge X.
One end of the cable has to be USB-C to plug into the iPhone 15. The other end should also be USB-C if you’re charging another iPhone 15. For any other model, the cable’s connector should be Lightning.
Connect the two handsets by the cable. If you’re using two iPhone 15 models, the one with more power will immediately begin recharging the one with less power. That’s your only option – you can’t send power to a handset with a higher battery level.
The situation is slightly different if you’re using an iPhone 15 to charge a previous version of the iPhone. Power will always flow from the iPhone 15 to the older model, no matter what their respective battery levels are.
In Cult of Mac testing, an iPhone 15 sends an iPhone 14 about 4W of power. That’s not particularly quick, but it’s perhaps enough to be useful.
Use with caution
Note that the power transfer isn’t 100% efficient, so dropping one iPhone’s battery level 10% won’t raise another by the same amount. Power is always wasted when charging any battery.
In our tests, an hour of charging brought an iPhone 14’s battery level up by 19% while lowering the iPhone 15’s battery level by 24%.
Bonus trick: Pass-through charging
There’s another way to use this capability that can be very convenient under the right circumstances. And it means you don’t have to drain your iPhone 15 to juice up another device.
Place the iPhone 15 on a wireless charger and then connect the charging cable to your AirPods, Apple Watch or another iPhone. Both devices will get power.
So if all you have access to is a wireless charger and a cable, multiple devices can get charged up simultaneously.
