iPhone 18 Pro Max battery capacity leaks — 5,187mAh cell photographed
Leaker @phonefuturist posted photos of what appear to be actual battery cells destined for Apple’s iPhone 18 Pro Max, giving us the most concrete look yet at the hardware inside next year’s flagship.
The images show two cells manufactured by Sunwoda Electronic Co., a major Apple supplier based in Shenzhen. One of them, model A3166, is rated at 3.903V with a 5,187mAh capacity. That’s actually smaller than two other iPhone 18 Pro Max battery capacities that leaked yesterday — a 5,425mAh version (for the dual-eSIM US model) and a 5,235mAh version (for European models that still include a physical nano-SIM slot).
It’s not clear whether the A3166 cell represents a third variant or an early prototype. But the broader trend is unmistakable: Apple keeps making its batteries bigger. Here’s how the Pro Max line has evolved:
| Model | EU (SIM+eSIM) | US (dual eSIM) |
|---|---|---|
| iPhone 17 Pro | 3,998 mAh | 4,252 mAh |
| iPhone 18 Pro | 4,056 mAh | 4,288 mAh |
| iPhone 17 Pro Max | 4,823 mAh | 5,088 mAh |
| iPhone 18 Pro Max | 5,235 mAh | 5,425 mAh |
The European iPhone 18 Pro Max (nano-SIM plus eSIM) packs 5,235mAh, up 412mAh or 8.5% from the iPhone 17 Pro Max. The US model, which ditches the SIM tray entirely for dual eSIM, reaches 5,425mAh — a 6.6% increase over its predecessor’s 5,088mAh.
Those are big numbers even before considering the efficiency gains of the A20 Pro chip expected to power the iPhone 18 Pro series. Combined with TSMC’s more advanced 2nm process, the battery life gap between the Pro Max and the rest of the lineup could widen significantly.
The iPhone 18 Pro series is expected to launch in September 2027, so these specifications could still change. But if these capacities hold, the iPhone 18 Pro Max would be one of the highest-capacity phones Apple has ever shipped — and a clear signal that the company is prioritizing all-day battery as a key selling point.