You plug your phone in at night with a full charge, and in the morning it is noticeably lower — even though the screen was off the entire time. Or you unplug it at 100% and by lunchtime it is at 30%. Either way, the battery is going down faster than it should, and it is not obvious why.
What is probably happening
Your phone does not truly sleep when the screen is off. Apps continue running in the background, checking for new messages, updating their data, tracking your location, and waiting for notifications. Some of this is necessary and expected. But some apps do far more background activity than they should, and a few common settings make the whole problem significantly worse.
The most common causes of fast battery drain:
- Too many apps refreshing in the background. Social media, news, and shopping apps in particular are designed to stay active so they can show you fresh content instantly.
- Push email. If your email is set to check for new messages constantly (push delivery), it is a continuous drain.
- Location services. Apps that track your location — even when you are not using them — use significant power.
- A poor mobile signal. When your phone has a weak signal, it works harder to maintain a connection. This is one of the most overlooked causes of battery drain.
- Battery age. After 2–3 years, most phone batteries hold notably less charge than when new. The problem is not that it drains faster — it is that there is genuinely less capacity to drain from.
- Screen brightness too high. The screen is the single biggest user of battery power. Even with the screen off, high brightness settings left on can compound other issues.
How to check battery usage
Both iPhone and Android show you which apps are using the most battery.
On iPhone: Go to Settings, then Battery. Scroll down to see the list of apps sorted by battery usage. Tap each app to see whether it used power in the background or only when you were using it. An app that shows significant background activity when you never use it in the background is a candidate to change.
On Android: Go to Settings, then Battery (sometimes under Device Care or similar). Look for Battery Usage. The exact location varies by phone manufacturer, but it is in the Settings app on every Android phone.
What is safe to try
Step 1. Look at the battery usage list and identify any apps using a large share of battery that you use rarely or not at all. Consider uninstalling those apps, or restricting their background activity.
Step 2. Turn off background app refresh for apps that do not need it. On iPhone this is in Settings, then General, then Background App Refresh. On Android you can restrict background use per app in the app’s settings under Battery or Restrictions.
Step 3. Review which apps have permission to use your location. On iPhone go to Settings, then Privacy and Security, then Location Services. Set apps you do not need to track your location to Never or While Using the App. On Android, go to Settings, then Location, then App Permissions.
Step 4. If you are in an area with poor signal (basement flat, rural location, a building with thick walls), consider turning on aeroplane mode at night if you do not need calls. Or turn off mobile data while keeping Wi-Fi on — Wi-Fi uses less power than a struggling mobile connection.
Step 5. Enable Low Power Mode (iPhone) or Battery Saver (Android) while overnight if the drain is severe. This is a holding measure rather than a fix, but it helps.
What NOT to do
- Do not close all your apps manually every time you use your phone. On modern iPhones and most Android phones, force-closing apps actually uses more battery because the phone has to start them from scratch next time. Only close an app if it is misbehaving.
- Do not leave your phone charging from a low-quality charger or cable overnight for years — this can degrade the battery faster than normal use would.
- Do not ignore an app that is consistently at the top of the battery usage list. That is usually worth investigating.
When the battery is old
On iPhone you can check your battery’s health in Settings, then Battery, then Battery Health and Charging. A battery at 80% maximum capacity means it only holds 80% of the charge it did when new — that is a real reduction. Apple says batteries are designed to retain 80% capacity at 500 charge cycles. If yours is significantly below 80%, a battery replacement will make a noticeable difference.
On Android, battery health information is less standardised, but some phones show it in Settings under Battery or Device Care. Third-party apps can read this information from some phones.
When to stop and seek help
If your battery drains from full to empty in a few hours with almost no use, or if the phone gets unusually hot while the screen is off, those are signs of a more significant problem — either a battery that needs replacing or an app behaving very badly. Take it to a repair shop or the manufacturer’s support.
If this did not work
If you have restricted background activity and location access and battery drain is still severe, a factory reset (after backing everything up) can sometimes clear software problems that cause unusual drain. However, try the other steps first as they are less drastic.
Frequently asked questions
Does leaving my phone charging overnight damage the battery?
Modern phones have protection that stops charging once they reach 100%, so it is not the risk it once was. However, many manufacturers recommend not charging to 100% constantly — some phones have an option to stop charging at 80% for this reason.
Should I let the battery fully drain before charging?
No. That advice is from older battery technology. Modern lithium batteries last longest when kept between roughly 20% and 80%, though occasional full charges are fine.
Does dark mode save battery?
On phones with OLED screens (most modern high-end phones), dark mode does genuinely save battery because black pixels on those screens are physically turned off. On LCD screens it makes little difference.
Why does my battery drain faster in winter?
Cold temperatures reduce the effective capacity of lithium batteries. Your phone will drain faster in cold weather, and the battery percentage may drop suddenly when it gets cold. This does not permanently damage the battery.
My phone is only a year old — is it normal for the battery to be worse?
Some degradation in the first year is normal. How fast it degrades depends on how often you charge it and whether you regularly let it get very hot. One year old at 90% capacity is typical.