One iPhone 18 Pro Max lasts longer than another — here is why
Russian tech channel Rozetked has conducted an extensive battery test of Apple‘s latest smartphones, comparing seven iPhone models to determine how the new generation performs against its predecessors.
The experiment focused on the iPhone 18 Pro and iPhone 18 Pro Max, including versions with physical SIM cards and eSIM-only configurations. The reviewers also examined whether Apple’s claims about improved battery life hold up under identical testing conditions.
All seven devices ran iOS 27.0.1 with their screens set to maximum brightness. Wi-Fi, automatic brightness adjustment and True Tone were disabled, while the phones continuously streamed TikTok videos over the same mobile network until their batteries ran out.
The experiment was repeated three times to verify the results:
Which iPhone lasted the longest?
The international iPhone 18 Pro Max with a physical nano-SIM card topped the test, lasting 10 hours and 7 minutes. Surprisingly, its US counterpart, which uses only eSIM, lasted exactly one hour less despite having a larger battery.
| Model | Battery life |
|---|---|
| iPhone 18 Pro Max (nano-SIM) | 10h 7m |
| iPhone 18 Pro Max (US eSIM) | 9h 7m |
| iPhone 17 Pro Max (eSIM) | 7h 48m |
| iPhone 18 Pro (eSIM) | 7h 47m |
| iPhone 18 Pro (nano-SIM) | 7h 27m |
| iPhone 17 Pro (eSIM) | 6h 52m |
| iPhone 17 | 5h 49m |
The difference between the two iPhone 18 Pro Max variants was particularly notable. The US model has a 5,567 mAh battery, compared with 5,390 mAh in the international nano-SIM version.
Rozetked attributed the unexpected outcome to differences in cellular modems. The US iPhone 18 Pro Max uses Qualcomm’s Snapdragon X80, while international versions feature Apple’s newer C2 modem.
The channel’s results suggest that the C2 may offer substantially better energy efficiency during sustained mobile-data use, although other hardware differences could also affect battery life.
Does iOS 27 affect battery life?
The test also highlighted differences between software versions. Rozetked previously recorded 9 hours and 33 minutes of battery life on the iPhone 17 Pro Max running iOS 26.3. On iOS 27.0.1, the same model lasted only 7 hours and 48 minutes.
The iPhone 18 Pro with eSIM almost matched the older Pro Max on the latest software, supporting Apple’s claim that its smaller flagship offers comparable endurance. However, the reviewers found that the iPhone 17 Pro running iOS 26.4 had previously lasted 8 hours and 33 minutes, outperforming the newer iPhone 18 Pro in the latest experiment.
Rozetked plans further testing following future iOS 27 updates to determine whether software optimisation improves battery performance.
