Fresh test results from Tom’s Guide have brought the issue to light. From their report:
As noted, the report also reveals the impact 5G could have on battery life compared to previous models of iPhone. Surfing AT&T’s 5G network, the iPhone 12 lasted 8 hours and 25 minutes. By way of comparison, the iPhone 11 was good for 11 hours and 16 minutes of 4G surfing conducting the same test, revealing the dent 5G can make in your expected usage time.
Further confirming this, switching the iPhone 12 to 4G-only boosted the iPhone 12’s performance to 10 hours and 23 minutes, a big improvement on the 5G test but still not enough to match the iPhone 11.
As Tom’s Guide notes, this would seemingly put the iPhone 12 at a disadvantage versus its Android competitors, losing out to phones including the Galaxy S20 (at 60Hz, not 120Hz), and the Google Pixel 5.
The iPhone 12 Pro did fair better in 5G testing, offering 5G and 4G battery life of 9 hours 6 minutes and 11 hours 24 minutes respectively. The latter 4G result seems to be the only parameter in which the iPhone 12 outperformed the iPhone 11. The iPhone 12 Pro’s results also made for a much more competitive showing against its Samsung rivals.
The only key thing to remember is that this test doesn’t account for Apple’s new Smart Data Mode, which can automatically switch between 4G and 5G depending on usage, optimizing both battery life and data consumption. However, the 4G-only iPhone 12 test seems to confirm that whilst Smart Data Mode might improve the iPhone 12’s overall battery performance, it may not be enough to compete with either similar Android devices or last year’s iPhone 11.