Apple could once again increase battery capacities across its Pro lineup this year. A new leak shared by Weibo tipster 麦子俊i (Mai Zijun) has revealed the alleged battery capacities of the upcoming iPhone 18 Pro Max, and the numbers are noticeably higher than the current generation.
Just like the iPhone 17 Pro Max, Apple is preparing two versions of the iPhone 18 Pro Max: one with a physical SIM tray for markets like China and another eSIM-only model for regions such as the US. Unsurprisingly, the eSIM version is once again tipped to pack a larger battery.
iPhone 18 Pro Max to Pack a 5,425 mAh Battery
According to the leak, the physical SIM variant of the iPhone 18 Pro Max could feature a 5,235 mAh battery, while the eSIM-only model may carry an even larger 5,425 mAh cell.
The standard iPhone 18 Pro, on the other hand, is reportedly getting only a modest increase. The physical SIM variant is said to feature a 4,056 mAh battery, while the eSIM version could pack a 4,288 mAh cell.
ALSO READ: iPhone 18 Pro Series and Apple’s First Foldable Could Debut on September 8, Says Gurman
Here’s how the new capacities compare with the previous generation:
| Variant | iPhone 17 Pro Max | iPhone 18 Pro Max | Increase |
| Physical SIM | 4,823mAh | 5,235mAh | +412mAh (+8.54%) |
| eSIM | 5,088mAh | 5,425mAh | +337mAh (+6.62%) |
| Variant | iPhone 17 Pro | iPhone 18 Pro | Increase |
| Physical SIM | 3,988mAh | 4,056mAh | +68mAh (+1.7%) |
| eSIM | 4,252mAh | 4,288mAh | +36mAh (+0.8%) |
iPhone 18 Pro and Pro Max Will Be Heavier
The leak also suggests that both iPhone 18 Pro models could gain some weight this year. The iPhone 18 Pro is said to weigh around 210g, while the iPhone 18 Pro Max could come in at approximately 242g. For comparison, the iPhone 17 Pro weighs around 204g, while the 17 Pro Max tips the scale at 233g.
Mai Zijun claims the added weight comes from a combination of a larger vapor chamber cooling system, bigger batteries, and a larger camera module.
Apple Refuses to Use Silicon-Carbon Batteries
Another interesting detail from the tipster is Apple’s continued reluctance to adopt silicon-carbon battery technology, which many Android brands already use. The company is also expected to continue using steel-cased batteries, which can improve heat dissipation and help reduce battery expansion over time.
Apple’s Battery Lead Over Samsung Only Widens Now
A 5,425mAh battery would give the eSIM version of the iPhone 18 Pro Max the largest battery ever seen on a Pro Max iPhone. Meanwhile, Samsung’s Galaxy S26 Ultra still ships with a 5,000 mAh battery, which means Apple’s flagship could offer a battery that’s roughly 9% larger. Apple already has an edge in battery endurance, so if Samsung sticks with a 5,000 mAh cell on the Galaxy S27 Ultra, the gap could widen even further.
As always, these details are based on early leaks, so plans could still change before Apple officially unveils the iPhone 18 series in September.
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