Charged your phone before bed, only to find it down by 10-20% in the morning, even though you didn’t use it? Even worse if you have work or classes to get to. The truth is, even in standby mode a smartphone can actively drain power because of background updates, battery wear, or overheating. Let’s look at why your phone loses charge overnight, what exactly is “eating” the battery, and how to fix it quickly.

Why Your Phone Discharges Overnight in Standby Mode

Sometimes it feels scary to even touch your phone because it drains that fast. The reason is that, even when you’re not playing blackjack online or watching movies with a bright screen, it remains active: sending notifications, updating apps and data, syncing cloud storage, and constantly searching for a network.

There’s a good chance background updates and syncing are to blame. Email apps, messengers, and social networks regularly connect to servers to “fetch” new messages and notifications. Every single alert uses up a portion of the battery, especially if your network is unstable and the phone is constantly reconnecting. It keeps searching for a stronger signal, jumping between E, 3G, LTE, and 4G.

Location services can also be a culprit. If you have location tracking enabled (for example, “Find My iPhone” or fitness apps), the phone periodically pings the GPS module, which consumes extra energy.

Another factor is app and system updates. By default, both iOS and Android are set to automatically install updates. When your phone is connected to Wi-Fi and has enough charge, it will download and install new software versions, draining power.

And we can’t ignore battery wear. Over time, battery capacity decreases, meaning the real energy reserve may be noticeably less than the original. As a result, even minimal background processes can drain 10-20% overnight.

How to Check Which Apps Are Draining the Battery

To find out which apps are consuming power, check your battery usage stats. You can usually do this in Settings.

For an iPhone

Open Settings → Battery.
Wait for the statistics to load.
Choose either “Last 24 Hours” or “Last 10 Days” to view usage data.
In the “Battery Usage by App” section, you’ll see a list of apps and the percentage of charge each has consumed. Tap on any app to also view how long you’ve used it.

For Android

Open Settings → Battery.

Wait for the usage chart to appear.

Below, you’ll see a list of apps with their percentage of battery consumption.

Tap any app to see details about screen-on time, standby time, and background usage. Depending on your Android model, the data may look slightly different.

How Much Charge a Healthy Battery Should Lose When Idle

In perfect conditions, when you’re not using your phone and background processes are minimal, a smartphone should lose 1-3% of charge per hour. That adds up to about 10-15% over eight hours of sleep.

For iPhones, with a battery in normal condition (capacity above 80%), standby losses are usually 1-1.5% per hour. On Android, the range is a bit wider: 1-2% per hour.

But if the battery has lost more than 20% of its original capacity, the numbers may increase: 2-4% per hour and 15-30% overnight. According to MDPI, battery wear raises internal resistance, causing more heat and energy loss. As a result, an old battery drains faster under the same load.

That said, you don’t necessarily need to replace it right away. Even with capacity slightly below 80%, you can still get by with charging once a day, if you cut down on background activity.

What to Do if Your Phone Drains Overnight

Now that we’ve covered the causes, let’s move on to the fixes.

For an iPhone

Restart the device. This helps if a system glitch is causing the issue. Press and hold the side button together with a volume button, slide to power off, then restart the iPhone.
Turn off background activity. Go to Settings → General → Background App Refresh. Disable auto-refresh for nonessential apps such as Mail or Maps.
Disable automatic downloads and updates. Open Settings → Apps → App Store → Automatic Downloads. Turn off both toggles: “App Updates” and “In-App Content.”
Limit location services. Go to Settings → Privacy & Security → Location Services. For each app, switch from “Always” to “While Using the App” or “Never.”
Enable Low Power Mode: Settings → Battery → toggle Low Power Mode. This automatically pauses background tasks and reduces load.

For Android

Restart your smartphone. Hold the power button and tap “Restart.”
Disable background data. Go to Settings → Battery → App Power Management (or Background Restrictions). Disable background activity and data for nonessential apps. You won’t be able to do this for system apps.
Limit auto-updates in Google Play. Open Google Play → Settings → Network Preferences → Auto-Update Apps. Choose between auto-updates only on Wi-Fi, on any network, or disable updates completely.
Turn off location services and network scanning. Go to Settings → Location. Set “Allow only while using the app” for specific apps or disable entirely.
Use Battery Saver mode. The icon is usually found in the quick access menu and looks like a battery. Enable it at night to slow down discharge.