Today I let the phone and case drain down completely - to the point where the iPhone shut down. Using a 30w USB-C Lightning connection, these are the times it took to charge. What's really interesting is that with USB-C, the case and phone charge in parallel.

1hr

  • iPhone 85%
  • Smart Battery Case 79%

1hr 15 mins

  • iPhone 93%
  • Smart Battery Case 90%

1hr 24 mins

  • iPhone 96%
  • Smart Battery Case 96%

1hr 30 mins

  • iPhone 97%
  • Smart Battery case 98%

1hr 32 mins

  • iPhone 98%
  • Smart Battery Case 100%

1hr 40 mins

  • iPhone 100%
  • Smart Battery Case 100%

Update:

When I left the iPhone unattended all night, by 10:30 am, the battery had dropped by 10%. I think this because I had Dark Sky constantly using Location Services. I'm also going to make it a practice now to have the XS Max on Low Power Mode unless I'm away from the house and keep Bluetooth disabled. This is because I have my computer and iPad, should I need them.