iPhone 6 iOS 8.4 Overnight battery drain

Hello ,

Thanks for using Apple Support Communities.

From your post I see your iPhone is discharging quickly at night. To start troubleshooting this issue I'd like you to follow the battery optimization steps below, and also find out what is taking up battery on your iPhone.

Always make sure your device is using the latest version of iOS.

• If you are using iOS 5 or later, see if you need an update. Go to Settings > General > Software Update.
• If an update is available, you can plug your device into a power source and update wirelessly or plug it into your computer and update with the latest version of iTunes.

Learn more about updating iOS

There are two simple ways you can preserve battery life — no matter how you use your device: adjust your screen brightness and use Wi-Fi.

Dim the screen or turn on Auto-Brightness to extend battery life.

• To dim, swipe up from the bottom of any screen to open Control Center and drag the Brightness slider to the left.
• Auto-Brightness adjusts your screen to lighting conditions automatically. To activate it, go to Settings > Display & Brightness and set Auto-Brightness to On.

When you use your device to access data, a Wi-Fi connection uses less power than a cellular network — so keep Wi-Fi on at all times. There are two ways to turn on Wi-Fi:

• Swipe up to open Control Center, tap the Wi-Fi icon, and log in to a Wi-Fi network.
• Go to Settings > Wi-Fi to access a Wi-Fi network.

iOS 8 is designed to be the most battery-efficient iOS ever. And it gives you more precise ways to manage your device’s battery life, because you can see the proportion of your battery used by each app (unless the device is charging). To view your usage, go to Settings > General > Usage > Battery Usage.

Here are the messages you may see listed below the apps you’ve been using:

Background Activity. This indicates that the battery was used by the app while it was in the background — that is, while you were using another app.

• To improve battery life, you can turn off the feature that allows apps to refresh in the background. Go to Settings > General > Background App Refresh and set the switch to Off.
• If the Mail app lists Background Activity, you can choose to fetch data manually or increase the fetch interval. Go to Settings > Mail, Contacts, Calendars > Fetch New Data.

Location and Background Location. This indicates that the app is using location services.

• You can optimize your battery life by turning off Location Services for the app. Turn off in Settings > Privacy > Location Services.
• In Location Services, you can see each app listed with its permission setting. Apps that recently used location services have an indicator next to the on/off switch.

Home & Lock Screen. This indicates that the Home screen or Lock screen was displayed on your device. For example, the display was awakened by pressing the Home button or by a notification.

If an app frequently wakes your display with notifications, you can turn off push notifications for the app in Settings > Notifications. Tap App and set Allow Notifications to Off.

No Cell Coverage and Low Signal. This indicates that either you are in a poor cell coverage area and your iOS device is searching for a better signal or that you’ve used your device in low-signal conditions, which has affected your battery life.

You can optimize your battery life by turning on Airplane mode. Swipe up to open Control Center and tap the Airplane mode icon. Note that you cannot make or receive calls while in Airplane mode.

Make sure your computer is plugged in and powered on when you’re using it to charge your iOS device via USB. If your device is connected to a computer that’s turned off or is in sleep or standby mode, your device’s battery may drain. Note that iPhone 3G and iPhone 3GS cannot be charged with a FireWire power adapter or FireWire-based car charger.

Take care.

Some app is running in background. You can solve the problem by simply charging your phone while you sleep. This has the added advantage that you can set up automatic iCloud backup and back up your phone overnight. This will work if the phone is connected to power and WiFi.

The phone is very smart about managing the battery life and charging rate; there is no need to unplug the phone when it is fully charged, because the internal charging circuit discontinues charging automatically when the state of charge reaches 100%.