An iPhone is not a general-purpose wireless battery-sharing pad for another iPhone. On supported USB-C iPhone models, however, you can use a cable to provide power to another compatible device. The phones determine which device supplies power based on their connection and battery state.
How to do it
- Use an appropriate USB-C cable to connect the devices. If the other device uses Lightning, use a USB-C-to-Lightning cable.
- Wait a few seconds for the devices to negotiate the connection.
- Look for the charging indicator on the device receiving power.
- Disconnect the cable when you no longer need to share power.
Wireless battery sharing
Do not expect the back of an iPhone to act like the reverse-wireless-charging feature found on some other phones. MagSafe lets an iPhone receive wireless power from a compatible charger, but that is different from using the iPhone itself as a wireless charging pad.
Why charging may be slow
Phone-to-device charging is intended for convenience rather than fast charging. Cable type, battery levels, temperature, and the connected accessory can affect whether power is supplied and how quickly it charges.
Before you finish
Menu names can change slightly between iOS releases, iPhone models, carriers, and app versions. If your screen does not exactly match these instructions, install available software updates and look for the same feature under the closest matching Settings section. Avoid changing unrelated security, privacy, or account options simply to make a missing control appear.
After making the change, test the feature once so you know the result is what you expected. If the setting affects an account, cellular service, privacy protection, or device security, keep your account credentials and a recent backup available before doing additional troubleshooting.