iPhone Duo Outer Display Edges iPhone 18 Pro Max in Battery Test

A new iPhone Duo battery test shows the foldable’s outer display lasting slightly longer than the iPhone 18 Pro Max, while the inner display lands a little below the iPhone 18 Pro. Apple rates the outer display for one hour less video playback than the iPhone 18 Pro Max, so the test result comes out a touch better than Apple’s own rating. The test ran the iPhone Duo twice, once opened and once closed, next to an iPhone 18 Pro and an iPhone 18 Pro Max. All four runs started at 100 percent battery health with adaptive power mode off. Brightness was matched across the phones with a light meter, with a separate match for each of the iPhone Duo’s two displays. Each phone cycled through video streaming, scrolling and social media, then heavier gaming, and repeated the loop until it shut down.

The iPhone Duo Battery Test Puts the Outer Display Level With the iPhone 18 Pro Max

The outer display margin was small, and a test that runs for many hours always carries some run-to-run variation, so the closed iPhone Duo is best read as matching the iPhone 18 Pro Max. Opened up, the iPhone Duo drained noticeably faster, finishing close to the iPhone 18 Pro but a little behind it. Apple’s battery life ratings point in the same direction. Video playback is rated at up to 44 hours on the outer display and 31 hours on the inner display, against 45 hours for the iPhone 18 Pro Max and 36 hours for the iPhone 18 Pro. Streamed video widens the gaps, with 37 hours on the outer display and 26 hours on the inner display against 40 hours for the iPhone 18 Pro Max and 33 hours for the iPhone 18 Pro.

Equal Use of Both Displays Puts the iPhone Duo Level With the iPhone 18 Pro

The typical use rating assumes equal time on both displays, and on that measure the iPhone Duo is rated for up to 24 hours. That matches the iPhone 18 Pro and trails the iPhone 18 Pro Max at up to 30 hours. Moving a session from the outer display to the inner display costs 13 hours of video playback and 11 hours of streamed video, so the split between screens sets which phone the foldable resembles. The two cells add up to a battery capacity of 4,883 mAh, which sits between the iPhone 18 Pro and the iPhone 18 Pro Max. The iPhone Duo is eSIM-only worldwide, so that capacity applies to every unit, while models with a SIM tray carry smaller batteries in some countries. US buyers get the larger eSIM-only versions of both iPhone 18 Pro models, the same versions used in the test. The iPhone Duo starts at $1,999 for 256GB in the US and reaches $3,199 for 2TB. https://www.youtube.com/watch?v=4gBS5b14izM