magsafe Wireless Charger with 18w charging head:
First, use Apple 18W PD charger with Apple MagSafe magnetic wireless charger to charge iPhone 13 Pro Max, the charger output 9V voltage, power 9.42W.
Replace the Apple 18W PD charger with an Apple 20W PD charger, and the output power of the charger is 8.93V 1.84A 16.53W.
Use the Apple 30W PD charger to charge the iPhone 13 Pro Max at 8.90V 1.40A 12.53W.