Apple is reportedly boosting battery capacity in its next flagship iPhones, with the upcoming iPhone 18 Pro Max expected to feature a record-breaking 5567 mAh battery in the US model. Leaked certification documents from China’s C3 agency reveal unusually large battery sizes for the iPhone 18 lineup, signaling a renewed focus on longer battery life.
Chinese insider Digital Chat Station spotted the filings on Weibo, which list a 4056 mAh battery for the iPhone 18 Pro in China and 4288 mAh for the US version. That’s a slight increase over the iPhone 17 Pro’s 3988 mAh (China) and 4252 mAh (US).
The bump is more significant for the iPhone 18 Pro Max, which shows 5391 mAh in China and 5567 mAh in the US. For comparison, the iPhone 17 Pro Max had 4823 mAh and 5088 mAh batteries in those respective regions. This difference largely stems from Apple ditching the physical SIM tray in US models starting with the iPhone 14, freeing internal space to fit larger batteries.
The certification documents don’t explicitly name the iPhone 18 models but feature battery codes that align with Apple’s upcoming flagships. The smaller Pro models use codes S2232 and S2233, while the Pro Max bears codes 2235L/2235 and 2236L/2236. These packs deliver an estimated energy capacity of 21.751 Wh, with a maximum charge voltage of 4.520 V. The certificates remain valid until mid-2031.
This data matches an earlier June leak from Digital Chat Station, lending it more credibility than typical rumors. The increased battery life is expected to be complemented by the new A20 Pro chip, reportedly built on a 2nm process, which promises better energy efficiency. Apple’s usual gains come from a combination of a power-efficient SoC, modem improvements, and strict background process management-not just bigger batteries.
While 5500+ mAh batteries are common among Chinese Android flagships in 2025 and 2026-many utilizing silicon-carbon anodes for higher capacity-Apple traditionally takes a more cautious, incremental approach. So a 5567 mAh battery on the iPhone 18 Pro Max is a notable jump without the fanfare often seen in Android circles.
Apple’s new iPhones are expected to launch in September alongside rumors of the company’s first-ever foldable iPhone. If these leaks prove true, the Pro models will not only boast larger batteries but also feature a smaller Dynamic Island notch, a variable aperture main camera, and a new C2 modem for markets outside the US. The real question will be whether the bigger batteries translate into longer actual usage or simply power new features like brighter displays and enhanced AI capabilities.