DEV Community

Docy
Docy

Posted on

18 Practical Tips to Reduce Battery Drain in Apple Apps

#ios #batteryoptimization #appledeveloperbestpractices #mobileperformanceengineering

In the mobile-first era, battery life is a decisive factor in user satisfaction. Regardless of how innovative your app is, it won’t succeed if it silently drains a user’s battery. Apple has set clear expectations for performance and efficiency, and failing to optimize your app for energy use can lead to user churn, poor reviews, or even App Store rejections.

This article presents 18 practical, developer-focused tips to minimize battery usage in your iOS apps, improve performance, and enhance long-term user engagement.

1. Use Background Modes with Caution

Apple allows specific background modes (e.g., audio, location updates, VOIP, etc.), but overuse or misuse can have serious consequences on battery life.
✅ What to do:

  • Only declare necessary modes in Info.plist under UIBackgroundModes.
  • Validate whether your app truly needs background execution or can defer tasks. 🔧 Example: 
<key>UIBackgroundModes</key>
<array>
    <string>location</string>
</array>
Misusing this for regular tasks like syncing data can drain battery fast and get your app flagged by Apple.
Enter fullscreen mode Exit fullscreen mode

2. Choose the Right Location Service

Location services are among the most battery-draining APIs. Apple provides multiple accuracy levels—choose the lowest accuracy needed.

✅ What to do:

  • Use kCLLocationAccuracyHundredMeters instead of kCLLocationAccuracyBest.
  • Consider startMonitoringSignificantLocationChanges() for non-critical updates.
  • Enable pausesLocationUpdatesAutomatically = true.

🔧 Example:

locationManager.desiredAccuracy = kCLLocationAccuracyHundredMeters
locationManager.pausesLocationUpdatesAutomatically = true
Enter fullscreen mode Exit fullscreen mode

3. Reduce Network Usage

Each network call wakes the radio. Too many small calls can consume excessive power.

✅ What to do:

  • Batch requests using a request queue.
  • Use background transfers with URLSessionConfiguration.background.
  • Enable HTTP compression and cache headers.

🔧 Example:

let config = URLSessionConfiguration.background(withIdentifier: "com.example.app.bg")
config.isDiscretionary = true
Enter fullscreen mode Exit fullscreen mode

4. Implement Smart Caching

Avoid redundant network calls by caching static or semi-static data.

✅ What to do:

  • Use NSCache for memory caching.
  • Store structured data using Core Data or UserDefaults.
  • Save large assets (images/videos) using FileManager.

🔧 Example:

swift
let imageCache = NSCache<NSString, UIImage>()
imageCache.setObject(image, forKey: "avatar")
Enter fullscreen mode Exit fullscreen mode

5. Optimize Timers and Scheduling

High-frequency timers drain battery by keeping the CPU awake.

✅ What to do:

  • Use longer intervals or coalescing timers.
  • For non-critical work, use DispatchSourceTimer.

🔧 Example:

swift
let timer = DispatchSource.makeTimerSource()
timer.schedule(deadline: .now(), repeating: .seconds(60))
timer.setEventHandler { performTask() }
timer.resume()
Enter fullscreen mode Exit fullscreen mode

6. Use BackgroundTasks API

iOS provides BGTaskScheduler to allow apps to schedule background work intelligently.

✅ What to do:

  • Use BGAppRefreshTask and BGProcessingTask to schedule background work when the system is idle or charging.
  • Always declare tasks in your Info.plist.

🔧 Example:

swift
let request = BGAppRefreshTaskRequest(identifier: "com.example.refresh")
request.earliestBeginDate = Date(timeIntervalSinceNow: 15 * 60)
try? BGTaskScheduler.shared.submit(request)
Enter fullscreen mode Exit fullscreen mode

7. Avoid Redundant Animations

Animations are GPU-intensive and can cause unnecessary rendering.

✅ What to do:

  • Avoid continuous animations.
  • Use UIViewPropertyAnimator to cancel animations when no longer needed.
  • Respect UIAccessibility.isReduceMotionEnabled.

8. Switch to Push Notifications Over Polling

Polling for updates frequently consumes network and power resources.

✅ What to do:

  • Use silent push notifications (content-available: 1) to trigger background fetch.
  • Limit push frequency to truly necessary updates.

9. Defer Work Until Better Conditions

Don't execute non-urgent tasks when the app is active or on cellular data.

✅ What to do:

  • Use QoS .background or .utility for deferrable tasks.
  • Use URLSessionConfiguration.allowsCellularAccess = false for large transfers.

10. Respect App Lifecycle

Continuing work after the app enters the background wastes battery and may violate App Store policies.

✅ What to do:

  • Pause tasks in applicationDidEnterBackground.
  • Save state and resume only when needed in applicationWillEnterForeground.

11. Batch Writes to Disk and Core Data

Frequent I/O operations can keep the device awake and degrade performance.

✅ What to do:

  • Use batch updates or bulk inserts in Core Data.
  • Minimize disk writes by caching and writing less often.

12. Profile with Xcode Instruments

The Energy Log in Instruments lets you see how your app affects system power usage.

✅ What to do:

  • Use the Energy tab in Instruments to check wakeups, CPU usage, networking.
  • Review thermal states and background activity patterns.

13. Avoid Unnecessary Sensor Usage

Sensors like accelerometer, magnetometer, and gyroscope are always-on once activated.

✅ What to do:

  • Call stopUpdates() when no longer needed.
  • Use lower frequency sampling rates.

🔧 Example:

swift

motionManager.stopAccelerometerUpdates()
Enter fullscreen mode Exit fullscreen mode

14. Support Dark Mode

OLED screens save battery in dark mode since black pixels consume less power.
✅ What to do:

  • Adopt traitCollection.userInterfaceStyle.
  • Use dynamic colors with UIColor.label, UIColor.systemBackground, etc.

15. Monitor Auto-Renewing Background Tasks

Tasks like video downloads or real-time uploads can keep network activity alive longer than necessary.

✅ What to do:

  • Provide in-app toggles to pause syncing.
  • Auto-pause tasks when app goes into background or on low battery.

16. Set Proper Background Fetch Interval

UIApplication.shared.setMinimumBackgroundFetchInterval() lets iOS know how often to wake your app.

✅ What to do:

  • Use UIApplication.backgroundFetchIntervalMinimum sparingly.
  • Temporarily enable fetch only when you expect important updates.

17. Eliminate Memory Leaks and Retain Cycles

Memory issues cause CPU overuse, leading to heating and battery drain.

✅ What to do:

  • Use Xcode’s Leaks and Allocations Instruments.
  • Fix strong reference cycles in closures and delegates.

🔧 Example:

swift

self.delegate = nil // when done
[weak self] in // use weak references in closures
Enter fullscreen mode Exit fullscreen mode

18. Offer Battery-Saving Mode to Users

Give power users control by offering a “Low Power Mode” inside your app.

✅ What to do:
Detect system low power mode using:

swift

if ProcessInfo.processInfo.isLowPowerModeEnabled { ... }
Disable animations, background sync, and heavy tasks when this is enabled.
Enter fullscreen mode Exit fullscreen mode

Final Thoughts

Battery optimization is not just a technical challenge—it’s a user experience priority. Each app competes for limited device resources, and users are increasingly conscious of which apps consume the most power. Apple enforces strict energy usage policies, and an unoptimized app is likely to receive poor reviews or App Store rejection.

By following the 18 tips above, you can ensure that your app behaves as a respectful citizen on the user’s device. These changes will improve battery efficiency, device responsiveness, and ultimately, user satisfaction.

Top comments (0)