iPhone battery & charging

iPhone shows a battery health warning message

Messages under Battery Health, like reduced maximum capacity or performance management, are the phone's built-in diagnostics telling you the battery is aging. Reading the exact wording tells you what step to take.

Difficulty
Easy
Time
5 minutes to check
DIY cost
$0
Pro cost
$70–$100

Symptoms

  • A note appears under Settings > Battery > Battery Health & Charging
  • Maximum capacity is shown as a percentage below 100%
  • A message about 'Peak Performance Capability' or 'Service Recommended' appears
  • Phone performance feels reduced alongside the message

Likely causes

  • CommonNormal capacity loss from age and charge cyclesA capacity percentage below 100% simply reflects normal battery aging.
  • PossibleiOS has throttled performance to prevent unexpected shutdownsA 'Peak Performance Capability' note means the battery couldn't reliably supply peak power, so iOS manages it.
  • PossibleThe battery has degraded enough that Apple recommends serviceA 'Service Recommended' message specifically flags the battery as no longer meeting original specifications.
  • Less commonA very new or very heavily used battery giving an unusual readingOccasionally a reading looks off shortly after setup or heavy first-week use.

What to do

  1. Open Settings > Battery > Battery Health & Charging and read the exact message shown.
  2. Note the maximum capacity percentage listed just above any warning.
  3. If it only shows a capacity percentage with no other message, treat it as informational, not urgent, unless it's below 80%.
  4. If it mentions Peak Performance Capability, know that iOS is actively working to prevent shutdowns; a battery replacement will resolve it if performance matters to you.
  5. If it says Service Recommended, plan for a battery replacement soon, since Apple's own diagnostics have flagged it.
  6. Check whether real-world symptoms like fast drain or random shutdowns match what the message suggests.
  7. Update iOS to make sure you're seeing current diagnostics, since older versions display this differently.
  8. Decide whether to replace the battery based on both the message and how much the symptoms bother you day to day.

When to call a pro

A 'Service Recommended' or Peak Performance Capability message is Apple's own signal to get the battery replaced at an Apple Store or authorized provider.

Safety

Generally low risk

Generally low risk for a careful person. Stop if anything looks different from what this guide describes.

Related guides

Operator provides AI-generated troubleshooting information. It can be wrong. For safety-critical, electrical, gas, structural, medical, automotive safety, or other high-risk problems, consult a qualified professional.