Three years of using Apple's 80% charge limit on successive iPhone Pro Max models produced battery health readings between 88% and 97%. The latest result came from an iPhone 17 Pro Max, which showed 97% maximum capacity after 12 months and 277 charge cycles.

Apple's charge limit is designed to reduce battery wear by preventing an iPhone from regularly charging to 100%. The setting has been available on newer iPhones since 2023, although limiting the battery to 80% can reduce the amount of charge available during the day.

How the three iPhone models performed

The test covered an iPhone 15 Pro Max, an iPhone 16 Pro Max and an iPhone 17 Pro Max. Each device continued using the 80% limit, including after the older phones were replaced as primary devices.

  • iPhone 15 Pro Max: 88% maximum capacity after 36 months and 369 cycles.
  • iPhone 16 Pro Max: 93% maximum capacity after 24 months and 343 cycles.
  • iPhone 17 Pro Max: 97% maximum capacity after 12 months and 277 cycles.

The iPhone 15 Pro Max and iPhone 16 Pro Max each reported 94% capacity after their first 12 months. The iPhone 17 Pro Max performed better over its first year, although the result cannot establish that the charge limit alone caused the difference.

Why the iPhone 17 Pro Max may have done better

The newer model has a larger battery and faster charging, which made the 80% limit easier to use day to day. It also uses an aluminum design and vapor chamber cooling. The device spent less time feeling uncomfortably warm than the iPhone 16 Pro Max, and improved thermal management may have contributed to the stronger battery-health reading.

Charging habits also changed during the latest test. More charging was done over USB-C than with Qi2 or MagSafe, but there was no way to determine whether that change made a meaningful difference. The phone was generally kept above 20%, and its larger battery resulted in fewer cycles than the previous model.

Is an 80% limit worth using?

The results suggest that the setting can help preserve capacity, but they do not prove how much benefit it provides compared with charging to 100%. The 97% reading after one year may not be far from the battery health of an iPhone used without the limit, while giving up 20% of available capacity can be inconvenient.

For users who need the extra runtime, Optimized Battery Charging offers a less restrictive option by reducing the time an iPhone remains fully charged. Apple also provides 90% and 95% limits, which may offer a middle ground. Another approach is to keep the 80% limit enabled and temporarily disable it on days when a full charge is needed.

The older test devices also retained capacity well during periods of light use. The iPhone 16 Pro Max lost 1 percentage point over the latest year, while the iPhone 15 Pro Max showed no change. Those devices added only 44 and 17 cycles during that period, respectively, so the figures are not directly comparable with a heavily used phone.