MagSafe Charger Only Charges at Full 15W Speeds With Apple's 20W Power Adapter - MacRumors

Alongside the iPhone 12 and 12 Pro models, Apple introduced a new MagSafe charger that attaches to the magnetic ring in the back of the devices, providing up to 15W of charging power, which is double the speed of the 7.5W Qi-based wireless charging maximum.

YouTuber Aaron Zollo of Zollotech tested several first and third-party power adapter options with the iPhone 12 Pro and a MagSafe charger using a meter to measure actual power output.

Paired with the 20W power adapter that Apple offers, the MagSafe Charger successfully hit 15W, but no other chargers that he tested provided the same speeds.

The older 18W power adapter from Apple that was replaced by the 20W version was able to charge the ‌iPhone 12 Pro‌ using the MagSafe Charger at up to 13W, but the 96W Power Adapter and third-party power adapters that provide more than 20W were not able to exceed 10W when used with the MagSafe Charger.

For maximum charging speeds with the MagSafe Charger and an ‌iPhone 12‌ or 12 Pro, Apple's 20W power adapter is required, and older power adapter options won't work as well.

Third-party companies will need to come out with new chargers that use the particular power profile that Apple is using to provide the optimum amount of power before a third-party charger will be able to provide the full 15W with the MagSafe Charger.