How to Check and Improve iPhone Battery Health
Every iPhone battery wears down chemically — but how fast is largely up to your settings. Here's where to check the real numbers and what actually helps.
Quick answer
Go to Settings → Battery → Battery Health & Charging. \"Maximum Capacity\" shows how much charge the battery still holds versus new. Above 80% is officially normal; below that, Apple considers the battery ready for service and you'll notice shorter days.
What the numbers mean
- Maximum Capacity — chemical capacity versus new. Losing ~1% per month of heavy use is typical.
- Peak Performance Capability — says whether iOS has throttled performance to prevent unexpected shutdowns on a worn battery.
- Cycle Count (newer iPhones) — full charge cycles used; batteries are rated for hundreds of cycles.
Five settings that slow battery ageing
- Optimized (or 80%) Charging — in Battery Health & Charging. Time spent at 100% is what ages a battery; both options reduce it.
- Avoid heat while charging — remove thick cases for fast charging or MagSafe; heat is the battery's worst enemy.
- Low Power Mode on long days — fewer background wakeups means fewer cycles burned.
- Background App Refresh audit — Settings → General → Background App Refresh; turn off apps you don't need updating silently.
- Screen brightness auto — the display is the biggest single consumer; keep Auto-Brightness on (Settings → Accessibility → Display & Text Size).
Troubleshooting
Battery draining suddenly after an iOS update? Give it 48 hours — indexing and re-syncing settle down. Still bad? Check Settings → Battery for the app ranking and look for one app dominating \"background activity\". Capacity dropped fast? Frequent fast charging in hot conditions accelerates wear; a certified battery replacement restores full capacity.
Frequently asked questions
Is it bad to charge my iPhone overnight?
No — charging stops at full, and Optimized Charging deliberately delays reaching 100% until near your wake time. Overnight charging with optimization on is close to ideal.
Should I let the battery run to 0%?
No. Deep discharges add wear on lithium batteries. Topping up in the 20–80% range is gentler than full cycles.
At what battery health should I replace it?
Below 80% capacity, or whenever Peak Performance Capability reports throttling. A battery swap makes an old iPhone feel dramatically faster and longer-lasting.