This is versus the Intel version which lasted 10 hours and 21 minutes, which is still pretty decent all things considered, but to squeeze out an extra 6 hours is indeed a very impressive upgrade. However, it seems that even Apple did not believe that the M1 performed as well as it did, and even suggested that there might have been a bug with the battery indicator.
Speaking to Tom’s Guide, Bob Borchers, VP of worldwide product marketing for Apple said, “When we saw that first system and then you sat there and played with it for a few hours and the battery didn’t move, we thought ‘Oh man, that’s a bug, the battery indicator is broken,’ and then Tim’s laughing in the background, ‘Nope, that’s the way it’s supposed to be’ and it was pretty phenomenal.”
Apple is expected to launch refreshed MacBook Pros later this year, possibly with the M1X chipset, so it will be interesting to see how the newer chipsets handle battery usage.