A new leak suggests Apple’s upcoming iPhone 17 Pro Max, expected this September, will come with the biggest battery ever seen in an iPhone. More details have emerged about what this could mean for performance and battery life.

Bigger Battery Than iPhone 16 Pro Max
According to a post from Weibo user Instant Digital—a source with a mixed but occasionally accurate track record—the iPhone 17 Pro Max could feature a ~5,000mAh battery, surpassing the iPhone 16 Pro Max’s 4,676mAh cell. This would mark a significant capacity increase, potentially improving endurance.
Rumors have long suggested the iPhone 17 Pro Max will be slightly thicker than its predecessor, with some of that extra space dedicated to a larger battery. The iPhone 16 Pro Max is 8.25mm thick, while the 17 Pro Max is expected to measure 8.725mm—an increase of less than half a millimeter. While the change may seem minor, it could still enhance battery life noticeably.
Will Battery Life Actually Improve?
A bigger battery is the most direct way to extend a phone’s runtime, but other factors play a role:
- New processor efficiency (likely the A19 Pro) could optimize power usage.
- Software enhancements in iOS 18 may further improve energy management.
- New features (like rumored vapor chamber cooling) could impact power consumption differently.
As 9to5Mac notes, “While a 10% capacity increase is significant, battery life improvements aren’t always 1:1.” Still, if Apple optimizes efficiency alongside the larger battery, users could see meaningful gains.
Estimated Battery Life Gains
Apple claims the iPhone 16 Pro Max offers 33 hours of battery life, up from 29 hours on the 14 Pro Max and 28 hours on the 13 Pro Max. The iPhone 12 Pro Max, by comparison, lasted just 20 hours.
With an extra ~300mAh, MacRumors estimates the iPhone 17 Pro Max could reach 35 hours or more of battery life—setting a new record for iPhones.
However, Apple Insider’s William Gallagher cautions that “a larger battery doesn’t guarantee longer runtime,” as new hardware features could offset gains. Still, if Apple balances power efficiency with capacity, users may finally get the extended battery life they’ve been asking for.
Why Battery Life Still Matters Most
Despite flashy new features, battery life remains a top priority for users. As the report notes, “Even if your phone can do incredible things, it’s useless if it dies by lunchtime.”
If the rumors hold, the iPhone 17 Pro Max could deliver the best battery performance in Apple’s history—making it a strong contender for power users.
Final Thoughts
- ~5,000mAh battery (up from 4,676mAh in iPhone 16 Pro Max).
- Slightly thicker design (8.725mm vs. 8.25mm).
- Potential for 35+ hours of battery life, depending on optimizations.
- New A19 Pro chip & iOS 18 efficiency improvements could further help.
While nothing is confirmed until Apple’s official announcement, the iPhone 17 Pro Max is shaping up to be a battery life champion.