MagSafe charger
if i use it with an Anker 20w adapter, will it harm the battery of the phone, and what will be the current rate of W for iphone 13 mini?
iPhone 13 mini, iOS 16
It should not harm the battery. It will still be at 15watts when possible. As explained in the support dsocument you posted from it will adapt to keep temperature low so it does not affect the phone or battery.