A new leak from Ice Universe claims the iPhone 18 Pro Max will pack a 5,500 mAh battery, an 8% jump over the iPhone 17 Pro Max's 5,088 mAh cell. The leaker says this comes with a penalty: weight rises to 240 grams from 233g, and thickness grows to 9mm from 8.75mm. That 0.25mm increase is explicitly tied to the larger battery, not the camera system.

Earlier rumors from Fixed Focus Digital pointed to a 2mm depth increase driven by a bigger camera plateau, not the battery. The two leaks conflict on both the magnitude and the cause of the size change. Ice Universe has a spotty track record, and Fixed Focus Digital is similarly inconsistent, so neither claim carries high confidence.

Apple never advertises milliampere-hours or highlights thickness gains, preferring to quote hours of video playback. The company has consistently delivered year-over-year battery-life improvements, so a runtime boost is probable. Whether users will feel the extra 7 grams or 0.25mm in hand is less certain.

If the 5,500 mAh figure holds, the iPhone 18 Pro Max would match the capacity of competing Android flagships like the Galaxy S25 Ultra, closing a long-standing spec gap. But the trade-off suggests Apple hit a density wall with current cell chemistry — gains now require physical volume.