TL;DR: Your iPhone battery drains fast because of Background App Refresh, location-hungry apps, a degraded battery, or a buggy iOS update. Check Settings, then Battery, then Battery Health to see your maximum capacity. If it is below 80 percent, Apple recommends service. Most other causes are fixable in under five minutes through settings changes alone.
How Do You Check iPhone Battery Health?
Open Settings, tap Battery, then tap Battery Health and Charging. The Maximum Capacity percentage tells you how much charge your battery holds compared to when it was new. Anything above 80 percent is considered normal by Apple.
Apple designed iPhone batteries to retain 80 percent of their original capacity after approximately 500 complete charge cycles, according to Apple Support documentation. A charge cycle is one full discharge and recharge, whether that happens in one session or across several partial charges. If your Maximum Capacity reads 85 percent, your battery holds 85 percent of the charge it held on day one.
The Battery Health screen also shows whether Peak Performance Capability is enabled. If iOS has detected an unexpected shutdown, it may throttle your processor to prevent future shutdowns. This throttling saves battery but slows your phone. Apple introduced this feature after the battery controversy of 2017 and now makes it fully transparent. If you see a message about performance management being applied, your battery is likely due for replacement.
Why Does Background App Refresh Drain So Much Battery?
Background App Refresh lets apps fetch new data even when you are not using them. Every refresh cycle wakes the processor, activates the radio, and burns battery. Disabling it for non-essential apps is the single highest-impact setting change you can make.
Go to Settings, then General, then Background App Refresh. You will see a list of every app with the toggle enabled. Social media apps, news readers, and email clients are the usual offenders. Apple’s own battery usage breakdown (Settings, then Battery) shows exactly which apps consumed power in the last 24 hours or 10 days, split between on-screen and background usage.
Disable Background App Refresh for any app that does not need real-time updates. Keep it on for messaging apps and navigation. Turn it off for games, shopping apps, and anything you open only occasionally. This single change can reduce background battery drain by 10 to 30 percent depending on how many apps had the toggle enabled, according to reports from Apple support forums and independent testing by iFixit.
How Much Battery Do Location Services Actually Use?
Location Services use GPS, Wi-Fi triangulation, Bluetooth, and cell tower data to pinpoint your position. Apps that track your location continuously, marked with a solid purple arrow in Settings, are significant battery drains.
Go to Settings, then Privacy and Security, then Location Services. Scroll through the list and look at the icons next to each app. A solid purple arrow means the app used your location recently. A hollow purple arrow means it has a geofence set. A gray arrow means it accessed your location within the last 24 hours.
Set most apps to “While Using the App” instead of “Always.” Weather apps, social media apps, and shopping apps rarely need constant location access. Apple’s own documentation recommends this approach. Navigation apps like Apple Maps and Google Maps need “Always” or “While Using” depending on your usage, but a food delivery app does not need to know where you are at 3 a.m.
If you want to investigate what else is silently consuming resources on your devices, our guide on Android storage that stays full after deleting everything covers a similar detective process for Android.
Does a New iOS Update Cause Battery Drain?
Temporary battery drain after an iOS update is normal and typically resolves within 48 to 72 hours. iOS re-indexes Spotlight, Photos, and other databases after every major update, which is CPU-intensive and power-hungry.
Apple Support acknowledges that post-update indexing temporarily increases battery consumption. If your battery drain persists beyond three days after updating, the issue is likely a bug in the release or a specific app that has not been optimized for the new iOS version. Check the App Store for pending app updates. Developers frequently push compatibility patches within the first week of a major iOS release.
| Battery Drain Cause | How to Identify | Fix | Impact |
|---|---|---|---|
| Background App Refresh | Settings > General > Background App Refresh | Disable for non-essential apps | High |
| Location Services (Always On) | Settings > Privacy > Location Services (purple arrows) | Switch to “While Using” for most apps | High |
| Post-update indexing | Occurs 24-72 hours after iOS update | Wait; charge overnight | Temporary |
| Degraded battery (below 80%) | Settings > Battery > Battery Health | Replace battery ($89-$119 at Apple) | Permanent fix |
| Display brightness | Manual brightness above 70% | Enable Auto-Brightness in Accessibility | Medium |
| Push email fetch | Settings > Mail > Accounts > Fetch New Data | Switch from Push to Fetch every 15-30 min | Medium |
| Widgets on Lock Screen | Lock Screen customization | Remove data-heavy widgets | Low-Medium |
If your drain started immediately after an update and the table above does not resolve it, a factory reset as a last resort can clear corrupted preference files. Back up via iCloud or Finder first.
What Is Optimized Battery Charging and Should You Enable It?
Optimized Battery Charging learns your daily charging routine and delays charging past 80 percent until you need it. Apple enables it by default, and you should leave it on. It reduces chemical aging of the lithium-ion cells.
Find it at Settings, then Battery, then Battery Health and Charging, then Optimized Battery Charging. When enabled, your iPhone learns what time you usually unplug it (say, 7 a.m.) and holds the charge at 80 percent overnight, topping off to 100 percent just before your alarm. This reduces the time the battery spends at full charge, which Apple’s documentation identifies as a primary cause of long-term capacity loss.
Lithium-ion batteries degrade faster when held at high charge states for extended periods. Apple’s battery technology page states that heat and sustained high voltage are the two largest contributors to capacity loss. Optimized Battery Charging addresses the second factor. Keeping your phone out of hot environments addresses the first. My opinion: this is the single best passive setting for extending battery lifespan, and disabling it to see 100 percent faster in the morning is a poor trade.
When Should You Replace Your iPhone Battery?
Replace your iPhone battery when Maximum Capacity drops below 80 percent or when you experience unexpected shutdowns. Apple charges between 89 and 119 dollars for out-of-warranty battery replacement depending on the model, at the time of writing.
Apple’s battery replacement pricing is published on their support page and varies by model. Older models like iPhone SE cost less than current-generation devices. AppleCare+ covers battery replacement at no additional cost if your battery drops below 80 percent capacity during the coverage period.
Third-party repair shops offer cheaper replacements, but Apple warns that non-genuine batteries may lack proper thermal management and safety protections. If you use a third-party battery, you will see a “Service” message in Battery Health and lose access to the detailed health reporting. For storage issues that compound the problem, our guide on freeing Gmail storage space can help you reduce cloud sync demands that contribute to battery drain.
A simple way to organize the rest of your digital and physical clutter is covered in our guide on organizing an apartment with no storage space. Learn more about how we research our content.
Frequently Asked Questions
Does closing apps save iPhone battery?
No. Apple has stated that force-closing apps does not save battery and can actually use more power. When you swipe an app away, iOS must reload it from scratch the next time you open it, consuming more CPU cycles and battery than simply resuming a suspended app. Leave apps in the background unless one is visibly misbehaving in the Battery usage screen.
Does dark mode save battery on iPhone?
On iPhones with OLED displays (iPhone X and later), dark mode saves battery because OLED pixels turn off completely when displaying black. Purdue University research found that dark mode at typical brightness levels saves 3 to 9 percent battery on OLED screens. On older iPhones with LCD screens, dark mode makes no measurable difference because the backlight stays on regardless of pixel color.
Is it bad to charge your iPhone overnight?
With Optimized Battery Charging enabled, overnight charging is not harmful. The feature holds the charge at 80 percent and completes the cycle before your typical wake time. Without it, the phone reaches 100 percent and trickle-charges for hours, which accelerates chemical aging. Apple designed this feature specifically to make overnight charging safe.
Why does my iPhone get hot and drain fast at the same time?
Heat and rapid drain occurring together usually point to a runaway background process, a poorly optimized app, or a failing battery. Check Settings, then Battery for any app consuming a disproportionate share. If no single app is responsible, restart your iPhone. Persistent overheating with rapid drain warrants a visit to Apple Support or an Apple Store, as it can indicate a hardware defect.
How many years should an iPhone battery last?
Apple designs iPhone batteries to retain 80 percent capacity after 500 complete charge cycles, which translates to roughly two to three years of typical use. Heavy users who charge to 100 percent daily may hit 500 cycles in 18 months. Light users who charge every other day may reach four years before hitting the 80 percent threshold.
Sources
- Apple Support, “iPhone Battery and Performance,” accessed at the time of writing.
- Apple Support, “Battery Health Management,” accessed at the time of writing.
- Apple, “iPhone Battery Service Pricing,” apple.com/support/products, accessed at the time of writing.
- Apple, “Batteries – Why Lithium-ion,” apple.com/batteries, accessed at the time of writing.
- iFixit, “iPhone Battery Replacement Guides,” accessed at the time of writing.
- Purdue University, “Dark Mode vs. Light Mode: Which Is Better for Your Phone Battery?” Proceedings of the ACM on Interactive, Mobile, Wearable and Ubiquitous Technologies, 2021.
