iPhone batteries are consumable parts. After a year or two, most people notice they don’t hold a charge like they used to. The good news is that small changes in how you charge and use your phone can dramatically slow battery degradation.
Understand Your Battery
iPhone uses lithium-ion batteries. A few key facts:
- Keeping the battery at 100% or 0% for extended periods accelerates wear
- Heat is the #1 enemy (anything above 35°C / 95°F is dangerous)
- Apple rates the battery for roughly 500 charge cycles
Check your battery health in Settings > Battery > Battery Health & Charging. If Maximum Capacity drops below 80%, it’s time to consider a replacement.
Enable Optimized Battery Charging
Introduced in iOS 13, this feature is genuinely useful. Your iPhone learns your wake-up schedule and holds charging at 80% overnight, then tops up to 100% right before you wake. This prevents the battery from sitting at full charge for hours.
Turn it on: Settings > Battery > Battery Health & Charging > Optimized Battery Charging.
Charging Habits to Avoid
Don’t Always Charge to 100%
Keeping the battery between 20–80% is the sweet spot for longevity. Ideal range is 40–80%. A realistic rule: start charging at 20%, stop at 80–90%. Avoid draining to 0% or leaving it plugged in all night at 100%.
Heat Is Your Battery’s Worst Enemy
Never charge in direct sunlight. Never leave your iPhone in a parked car in summer (temperatures can exceed 70°C inside). Remove the case during wireless charging — it traps heat.
Turn Off Battery-Draining Settings
| Setting | Where to Find It | Why |
|---|---|---|
| Auto-brightness | Settings > Display & Brightness | The screen is the biggest power drain |
| Background App Refresh | Settings > General > Background App Refresh | Stops apps from phoning home constantly |
| Precise Location Services | Settings > Privacy > Location Services > System Services | Saves significant battery |
| 5G → 5G Auto or 4G | Settings > Cellular > Voice & Data | 5G uses more power; 4G is plenty fast |
Bonus tips: Use Dark Mode (huge effect on OLED iPhones X and later). Add Low Power Mode to Control Center for quick access. Toggle Airplane Mode in areas with weak signal to stop your phone from hunting for towers.
Find Battery-Hungry Apps
Settings > Battery shows app-by-app usage for the last 24 hours or 10 days. Watch out for video streaming apps, heavy GPS apps (Uber Eats, weather), and chat apps (LINE, X, Instagram). If an unknown app is draining battery, restrict its background activity or set location to “While Using.”
When to Replace Your Battery
Signs it’s time: Maximum Capacity below 80%, phone shuts down around 30%, can’t charge past 80%, or you need to charge twice a day. Apple Store replacement for iPhone 15 is around ¥13,000; it’s free under AppleCare+ if capacity is below 80%.
Summary
Three golden rules: avoid heat, keep charge between 20–80%, and turn off settings you don’t need. Follow these and your iPhone battery can last 1.5x longer. Go turn on Optimized Battery Charging right now.