I so just recently installed the OEM Tesla Qi charger in my Model S and it just doesn't charge my Pixel 3 well. The phone says that it's charging, but only barely gains charge and sometimes it loses charge. I have MCU1, so that's obviously part of the problem, but even 5W charging should charge it slowly. I have a bumper case on it, so there's no additional material between the phone and the charger, just 1-2mm of air. I need to do some more testing with placement height and removal of the case, but it's not a good start.