Apple Testing Massive 5,800mAh Battery for Foldable iPhone, May Sacrifice Thinness [Report]

Apple is prioritizing battery life for its first foldable iPhone, testing cells in the 5,400mAh to 5,800mAh range, according to a new report. The information comes from supply-chain sources via leaker yeux1122 on Naver, who previously reported accurate capacity details during development of the iPhone Air.

If finalized, that capacity would easily surpass the 5,088mAh battery in the iPhone 17 Pro Max, currently the largest Apple offers. Much like early iPhone Air prototypes—which tested between 2,850mAh and 3,000mAh before settling higher—the foldable appears to be trending toward a larger cell. The report suggests Apple may accept a slightly thicker chassis to improve battery life, tempering earlier claims that the device would be a super-thin showcase. According to the source, development activity at major component suppliers also supports this direction.

The leaker also disputes recent rumors that the iPhone 18 Pro Max will become significantly heavier. They claim the Pro Max's dimensions are mostly locked in and that any added thickness or weight is more likely to appear in the next iPhone Air or the foldable model as Apple finalizes internal layouts.


Suppliers have reportedly begun stocking components for the foldable, which is expected to debut in late 2026 as part of a major hardware refresh.

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