Symptoms
- Battery Health percentage below 85%
- Phone doesn't last as long as it used to on a full charge
- Peak Performance Capability message appears
- Battery drains fast even with light use
Likely causes
- CommonNormal aging from charge cyclesLithium-ion batteries lose capacity gradually, typically reaching around 80% after 500 full charge cycles.
- CommonFrequent full discharges or extreme heat exposureLetting the battery hit 0% often or leaving the phone in hot cars accelerates wear.
- PossibleKeeping the phone plugged in at 100% for long periodsConstant full-charge states stress the battery over time, though Optimized Charging helps offset this.
- Less commonA single defective battery cellOccasionally a battery degrades unusually fast compared to its charge cycle count.
What to do
- Check Settings > Battery > Battery Health & Charging for maximum capacity percentage.
- Note the message underneath, if any, about peak performance capability.
- Compare how the phone performs now to a few months ago at similar charge percentages.
- Turn on Optimized Battery Charging if it isn't already, to reduce time spent at 100%.
- Avoid leaving the phone in direct sun, hot cars, or under a pillow while charging.
- Try to keep the battery generally between 20% and 80% for daily use when convenient.
- If capacity is below 80% and it's affecting daily use, that's the normal threshold for considering a replacement.
- Back up the phone before any battery service in case it requires a restart or restore.
When to call a pro
Once maximum capacity drops below about 80%, Apple or an authorized provider can replace the battery to restore full-day performance.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.