Quick Charging inside the car is equally important to those we had on the table top, with powerful smartphones nowadays, there are some models which are really draining fast when its being utilized to its full potential. In order to combat the quick drain is to do the reverse engineering, which is quick charge. Now most of us has quick chargers at home, but in the car there are still quite a few technology supporting this. How about wireless, where its already mounted on your car and you can use to navigate you while charging it on your dashboard.
This quick charger is easy to mount, actually it has 2 mount mode, one is stick on the dashboard or second is to clip on the aircon vent. These way either you want it on your eye level or below your eye level are quite okay. There are some countries which disallows phone to mounted above the dashboard, therefore the clip on the aircon vent is a good option. Id prefer the clip on the aircon vent its for the reason your phone can cool down a lot faster due to the cold air coming out from the vent.
The only Xiaomi phone i know now that supports the 20W wireless is the Mi 9 and user reported that it quite fast in charging, of course not as fast as the 27W but still. You need to plug it to the red USB 2 for support on fast charge mode.
Box packaging 
The Red USB is the Fast Charge 
Clip 
Best maximized with Mi 9!