iPhone (iOS) · System

Check Battery Health and Usage on iPhone

The Battery screen shows your battery's current health and charging behavior, breaks down which apps used the most power recently, and includes Low Power Mode for stretching a low charge further.

How to open Battery

  1. Open Settings → Battery.
  2. Review the usage chart for the last 24 hours or last 10 days.
  3. Tap 'Battery Health & Charging' to see Maximum Capacity and Optimized Charging status.
  4. Toggle Low Power Mode directly from this screen or from Control Center when you need to stretch a low charge.

What you should know

  • Battery Health & Charging shows Maximum Capacity and whether Peak Performance Capability is currently limited.
  • Optimized Battery Charging learns your daily routine and delays charging past 80% until closer to when you'll unplug.
  • Battery usage by app is available for both the last 24 hours and the last 10 days, broken down by screen-on and background time.
  • Low Power Mode reduces background activity, some visual effects, and mail fetch to extend remaining charge for the rest of the day.

All rechargeable lithium-ion batteries chemically age over time — a declining Maximum Capacity percentage is normal wear, not necessarily a defect, though very low capacity may warrant a battery service.

Why it matters

The Battery screen turns 'my phone doesn't last as long as it used to' into a measurable fact by showing Maximum Capacity, which naturally declines through normal chemical aging and directly explains shorter battery life on older devices. The per-app usage breakdown is also one of the fastest ways to diagnose a phone that's draining unusually fast, since a single misbehaving app in the background is a common and fixable culprit. Low Power Mode, meanwhile, is a genuinely useful safety net for getting through the rest of a day on a device that's about to die, without needing to find a charger immediately.

Best practices

  • Enable Optimized Battery Charging so your iPhone avoids sitting at 100% charge overnight, which reduces long-term battery wear.
  • Check the 10-day usage view periodically to catch an app quietly consuming excessive background battery before it becomes a daily annoyance.
  • Use Low Power Mode proactively when you know you'll be away from a charger for a while, rather than waiting until the battery is critically low.
  • Avoid extreme heat exposure (like a hot car dashboard), since high temperatures accelerate battery chemical aging more than normal charging cycles do.
  • Consider a battery service if Maximum Capacity drops well below 80% and you're noticing real day-to-day performance or longevity issues.

Common problems and fixes

Battery drains noticeably faster than it used to after an iOS update
Give the device a day or two after an update for background indexing to finish, then check Settings → Battery for a specific app using unusually high background power.
Maximum Capacity shows a low percentage and the phone shuts down unexpectedly at low charge
Check whether Peak Performance Capability shows a note about performance management, and consider a battery replacement if the device is out of typical battery health range.
iPhone won't charge past 80% overnight even with Optimized Battery Charging off
Check for a separate Charge Limit setting (on supported models) that may be capping charging independently of Optimized Battery Charging.
Low Power Mode keeps turning itself off after a restart
This is expected — Low Power Mode automatically disables once the battery charges above 80%, and doesn't stay on permanently across charge cycles by design.

Tips and tricks

  • Tap the clock icon next to the battery usage chart to switch between 'Last 24 Hours' (hourly detail) and 'Last 10 Days' (daily trend) views.
  • Add the Low Power Mode toggle to Control Center for one-tap access without opening Settings when your charge is running low.

Frequently asked questions

Is it bad for my battery to charge my iPhone overnight?

No, Optimized Battery Charging is designed specifically for this — it delays finishing the charge past 80% until shortly before you typically unplug, reducing the time spent at a full charge.

Does using Low Power Mode all the time damage my battery?

No, Low Power Mode simply reduces power-hungry background activity and doesn't harm the battery; it's safe to leave on indefinitely if you prefer the extended battery life over slightly reduced background performance.

What Maximum Capacity percentage means I should replace my battery?

Apple doesn't publish one universal cutoff, but many users consider a battery service once capacity falls significantly below 80%, especially if it's paired with noticeable shutdowns or rapid drain.

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