Today Apple has Confirmed that there will Variation in Wireless Charging Speeds With iPhone 12 Series Smartphones with Magsafe Chargers.
Coming to the Details iPhone 12, 12 Pro & 12 Pro Max Can Get 15W Wireless Charging Speed through Magsafe Charger. iPhone 12 Mini the Entry Level iPhone in 12 Series Can Charge Upto 12W with Magsafe Charger. The Speed of the Charging to iPhone Changes When Temperature Raises, Current Battery Percentage & Activity Running in iPhone.
Apple Support Document says that To Use 20W Power Adapter for the Charging spee of 9V@2.22A or 9V@2.56A on iPhone 12, 12 Pro & 12 Pro Max and 9V@2.03VA on iPhone @2 Mini.
Apple Says that You Should Connect Magsafe Charger into Power Source and Then Connect to iPhone. If you Connect to iPhone and next Connect to Power Source Then it will Run on Lower Charging Speeds ( 7.5W ) Until you Unplug the iPhone & Magsafe Charger for 3 Seconds.
Upto Now iPhone 12 & 12 Pro are In Market and 12 Mini & 12 Pro Max will Ship from November 6 and Magsafe Charger Costs $39. Stay Tuned To Mobiradar for More Information.