Fresh leaks suggest the upcoming iPhone 18 Pro Max could feature the biggest battery ever seen in an Apple smartphone. The latest information also indicates that battery capacity may differ depending on whether the device supports only eSIM or includes a physical nano-SIM tray.
According to a tipster, the eSIM-only version of the iPhone 18 Pro Max could arrive with a 5,425mAh battery. Meanwhile, markets that continue to receive a physical SIM slot are expected to get a slightly smaller 5,235mAh battery. The reported difference is believed to be due to the extra internal space created by removing the SIM card tray.
Another earlier leak also revealed the expected battery capacities of the iPhone 18 Pro. The physical SIM variant is tipped to feature a 4,056mAh battery, while the eSIM version could include a larger 4,288mAh unit.
For comparison, the iPhone 17 Pro is reportedly equipped with 3,998mAh and 4,252mAh batteries in its physical SIM and eSIM versions, respectively. The iPhone 17 Pro Max is said to feature a 4,823mAh battery in markets with a SIM tray and a 5,088mAh battery in eSIM-only regions.
If these leaks are accurate, the iPhone 18 Pro Max will receive a bigger battery upgrade than the standard Pro model. The device is also expected to be powered by Apple’s rumoured A20 Pro chipset, which is believed to be built using a 2nm manufacturing process. The combination of a larger battery and a more power-efficient processor could improve battery life, although actual performance will also depend on software optimisation and display efficiency.
The leak also notes that Samsung’s Galaxy S26 Ultra currently offers a similar battery size to the iPhone 17 Pro Max, while the Galaxy S27 Ultra is rumoured to feature a 5,500mAh battery. Meanwhile, Chinese flagship smartphones such as the Xiaomi 17 Pro Max, Oppo Find X9 Pro, and OnePlus 15 already feature batteries of around 7,500mAh, with some upcoming Android flagships expected to approach 9,000mAh before the end of the year.
Apple is widely expected to unveil the iPhone 18 series in September 2026. However, the leaked battery specifications remain unconfirmed until the company makes an official announcement.
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