How to fix Galaxy S8 Plus with poor battery life [troubleshooting guide]

Like it or not, poor battery life is an expected issue for even top-of-the-line phones like the #GalaxyS8 and #GalaxyS8Plus. Needless to say, this is a common problem ever since the first smartphone was released so it’s no surprise that a lot of S8 Plus users are reporting the problem.
In this troubleshooting episode, we include three reports from some members of our community who reached out to us and our suggestions on how to go about this issue.

Here are the three cases:

Ever since the software update my phone’s battery is draining really fast, it used to give me 24 hours of battery time which is now reduced to less than 15 hours. My phone is the same as it was 2 days ago. — Ehsan

My Samsung Note 4 Battery drains so fast after its been 100% charged Also the phone gets hot while in use. What could be responsible. — Solaomisore1

Thank you for taking my question. Well it’s simple, my wife’s galaxy S8 Plus battery drains at a rate 5 times faster than my galaxy and we are trying to figure out why. These phones both have been recently reset to factory standards However, for what ever reason my wife’s phone will go from 100% to 15% in about 3-4 hours with minimal use (no phone calls or streaming anything).

I check all of her installed applications and they do not differ with my apps. (as a matter of fact I have more apps installed then she does – yet my phone works all day. Anyway, if you have any insight as to what may be causing this. Sadly I have to put my wife phone in ultra low power mode just to get her thru the day, and that should not be a solution. So…any insight as to what factory apps or installed apps could be causing this? Or another switched on function that I may not know about, as when you factory reset the device, there are many questions (Allows and Deny) that you have to answer.

Like I said, both phone have all the factory apps installed and your basic, Facebook, Twitter, Instagram, Messenger, and Flashlight apps added. Just can’t figure out what could cause such a drain on her phone that is not occurring on mine. Any insight…would be greatly appreciated. Thanks. –David

Solution: For these three users, there seems to be clear reason why their S8 Plus’ battery has poor life. While one (Ehsan) has mentioned that the issue appeared after installing an update, this problem can actually happen with or without an update installation. When it comes to the question of what may be causing a phone’s battery to empty faster than usual, the answer is often not straightforward. There can be many different reasons as each device is unique in its own way. Every user has his or her own usage habits as well so it’s not easy to pinpoint where the exact cause for a particular case lies. There are many factors to consider when dealing with battery drain or poor battery life on the Galaxy S8 Plus so we’re better off dealing with as many of them as possible. We’ll provide workarounds and solutions below and we’ll all label them as solution options. Fixing poor battery life is a hit-and-miss endeavor and sometimes, it may take a combination of steps to effectively handle it.

Solution #1: Restart your S8 Plus regularly

Bugs sometimes occur when a system has run for some time. To minimize bugs or software glitches, make sure that you reboot your phone at least once a week. This is a not a guaranteed fix for the specific issue we’re dealing right now but it’s a good first step to the right direction. If you haven’t yet, we suggest that you perform a soft restart instead of the usual restart to also clear the memory. Here’s how:

Press and hold the Power + Volume Down buttons for approximately 10 seconds or until the device power cycles. Note: Allow several seconds for the Maintenance Boot Mode screen to appear.
From the Maintenance Boot Mode screen, select Normal Boot. You can use the volume buttons to cycle through the available options and the lower left button (below the volume buttons) to select. Also, allow up to 90 seconds for the reset to complete.

Solution #2: Clear cache partition

Wiping the cache partition aims to refresh the system cache. This cache is used by Android to perform tasks efficiently, particularly when it comes to loading or running of apps. The more the operating system works efficiently, the lesser the pressure on the entire system, which in turn can be beneficial for the battery day in and day out. To clear your Galaxy S8 Plus cache partition:

Turn off the device.
Press and hold the Volume Up key and the Bixby key, then press and hold the Power key.
When the Android logo displays, release all keys (‘Installing system update’ will show for about 30 – 60 seconds before showing the Android system recovery menu options).
Press the Volume down key several times to highlight “wipe data / factory reset.”
Press Power button to select.
Press the Volume down key to highlight “wipe cache partition.”
Press the Power key to select.
Press the Volume down key to highlight “yes” and press the Power key to select.
When the wipe cache partition is complete, “Reboot system now” is highlighted.
Press the Power key to restart the device.

Solution #3: Lower screen brightness

If you haven’t known it yet, that bright, amazingly colorful screen on your S8 Plus is the biggest drain on your battery. If you constantly turn it on on full brightness, don’t expect the battery to last longer every day. The super packed pixels on that 6.2-inch screen demands a lot of computing power from both the processor and the graphics chip, which in turn, needs a lot of energy from the battery. Dimming the screen to 60% or even below 50% may give a lot of extra juice for the day. This is especially relevant if you use your phone often. Of course, we don’t want to tell you that this should now be the case from hereon. You can always revert to 100% brightness if you want but if you think you need stretch the usage of your S8 Plus for a few more hours in a day, this workaround might just be what you need.

Try to lower screen brightness to the lowest comfortable setting setting every day and you’ll see the result. In the long run, this will also help extend battery life because it will also decrease the amount of charge cycles on the battery everyday.

Solution #4: Check battery usage and address possible app issue

Aside from the screen being one of the biggest contributor to fast battery drain issue, apps can also be a culprit. A lot of apps nowadays have an online component, which means that they may employ services that constantly run in the background to receive updates and data even when you’re not actively using them. For example, Facebook app regularly needs updates for its News Feeds so it constantly runs so that it can communicate with remote servers and download new contents. The same general design has become the trend for even the simplest of apps so the more apps you install, the higher the possibility that there are multiple of them constantly hogging resources even when you’re asleep. To check what these apps are, you can go under Settings > Device maintenance > Battery > Battery usage. Under Battery usage screen, you should be able to see a list of apps that consume a lot of battery power for a certain period. From there, you can decide which apps to uninstall or modify its behavior so it no longer receives updates in real-time basis, if there’s an option for you to do so. So, for example, instead of allowing your email app to constantly communicate with email servers for new messages, you can set it to only download new emails when you manually tell it to. Other apps may not have the option to allow users to stop them from communicating with remote servers all the time so the best thing to do is to either disable them, or remove them entirely from the system. If you have apps in the list that you don’t recognize or remember that you install, they may be components of a malware attack, which is another reason why battery drain issue often occurs.

In general, use the battery usage list to know what to do next. Every user has its own needs so just try to be smart with your app usage and hopefully that will help.

Solution #5: Uninstall apps

As mentioned, apps is one of the main reasons why battery drain issue occurs. Many Android users install apps on impulse and forget about them days later. With its 128GB internal storage, that can mean a lot of apps just idling by while all the time hogging resources. Most games nowadays are like social media apps by design and they can drain the battery real bad if left installed for a long time.

No app is perfect so somewhere along the line, one of them may interfere with Android or cause coding-related bugs that can slow down the system. The more inefficient Android becomes, the more drain to the battery. This situation can easily get worse if you have multiple installed apps causing problems. To minimize the chances of apps causing the battery drain issue you’re experiencing, don’t hesitate to uninstall those you don’t need at all. Start with those apps that constantly refreshes its contents like social media apps or shopping apps. Facebook is one of the top reasons for battery drain issue across all mobile platforms but other social media apps out there can be just as problematic. Determine what apps to leave according to their use and get rid of those you only occasionally use. Or you can find better substitutes that may not be as problematic. Read app reviews and know what others are saying about the app. In general, stay away from apps that require near-constant internet connection to work.

Solution #6: Turn off AOD

While Always On Display has its use, we don’t recommend that you use it for similar reason as Solution #3. AOD can significantly drain the battery at a steady rate since the screen wil always be on. To turn it off, you can go under Settings > Display > Always On Display.

Solution #7: Turn off automatic uploads for apps or backups

Leaving your S8 Plus to upload photos, videos, backups, etc. on its own may be convenient but it can also be the cause why your phone may be losing power fast. We can’t be specific on what you need to do here since every user has its own way of setting their apps up. Try to go over your apps and review each of their settings to know if any of them is set to automatically upload something.

If you use Samsung Cloud services, try to configure it so that its components won’t upload files automatically. If you have thousands of photos in your Gallery app and you set Gallery under Samsung Cloud to ON, the upload may take a long time to finish, resulting to battery drain. The same scenario can occur with any other cloud services or apps.

Solution #8: Check for rogue apps

Bad or malicious apps can lead to all sorts of issues. Apps of this type also tend to use a lot of resources when running in the background so again, our advice above applies here as well. Again, take a deep look at the apps you have and screen each of them properly. A good rule of thumb for you here is to uninstall apps that you don’t recognize. Some apps are initially legitimate but after some time, they can turn malicious and allow malware to invade your phone. Because there’s a constant cat and mouse battle between security software and malicious developers, installing an antivirus app won’t always catch bad apps all the time. If you want to take phone security seriously, you should start by ensuring that you only install apps from reputable developers. Keep in mind that there’s no such thing as free apps. Creating an app is costly and developers usually recoup the expense they’ve spent on their products by using malicious tactics. Some may steal your personal data and sell them to other parties while others are there to do specific tasks, like force your phone to mine virtual currency without a user’s knowledge. In almost all cases, these unauthorized or malicious activities keep your phone busy all the time. Infected devices usually lags significantly and drains battery faster than expected.

Solution #9: Ensure apps and Android are up-to-date

Some bugs can only be fixed by installing a fix that comes in the form of patches. This is true for both Android operating system and apps so make sure everything is updated all the time.

Solution #10: Use Power Saving Mode

This is not a solutions but a workaround. Power Saving Mode is a useful feature that you can use if you need to stretch usage time from time to time. PSM basically transforms your phone into its dumb version by only allowing basic functions and slowing down the device. Good for days when the next charging session is hours away.

Solution #11: Factory reset

We only recommend factory reset if you’ve already exhausted all possible software solutions and workarounds. It mainly addresses the software side of a battery drain issue. In most cases, a reset is very helpful in fixing this type of problem so don’t hesitate to do it if nothing works so far. Here’s how to do it:

Back up data on the internal memory. If you have signed into a Google account on the device, you have activated Anti-theft and will need your Google credentials to finish the Master reset.
Turn off the device.
Press and hold the Volume Up key and the Bixby key, then press and hold the Power key.
When the Android logo displays, release all keys (‘Installing system update’ will show for about 30 – 60 seconds before showing the Android system recovery menu options).
Press the Volume down key several times to highlight “wipe data / factory reset.
Press Power button to select.
Press the Volume down key until ‘Yes — delete all user data’ is highlighted.
Press Power button to select and start the master reset.
When the master reset is complete, “Reboot system now” is highlighted.
Press the Power key to restart the device.

Solution #12: Get professional help

If battery drain still happens even after a factory reset, there must be a hardware issue behind. Make sure that you contact Samsung so they can help you with it.