Can Mate 20 Pro use Mate 10 Pro charger?

You can use Mate 10 Pro charger but the charging will not be a fast. The original charger of P20 Pro can support 40w.

The Mate 20 Pro charger supports 10V/4A, or 9V/2A or 5V/2A. So, it supports 40W SuperCharge. I think Mate 10 Pro charger supports 5/2A, 4.5V/5A, 5V/4.5A, and therefore the max it will goes is 22.5w charging.

You can use the Mate 10 Pro charger but it will not charge at the max of 40W to reach 70% in 30 minutes. I think it’s better you use back the original charger.