I have seen that many battery-related issues have been trending in this forum. So, I decided to write a detailed guide on batteries.

Defining types of users

First, we have to understand how a user uses their device. Usually, there are three types of users: light, medium, and powerful. Below, I am going to define all three types of users. You can choose which category you fall into. They can be a bit subjective.
 
Light user
Light users are involved in tasks like making calls, sending messages, checking emails, occasional web browsing, and minimal app usage. They don't heavily multitask or use resource-intensive applications. On average, they get 1–2 days of battery backup.
 
Medium user
Medium users engage in tasks like moderate web browsing, social media, occasionally streaming music and videos, and some app usage. They multitask, but they don't push their device to its limits with constant heavy usage. They get around 12–24 hours of battery backup.
 
Power user
Power users are individuals who heavily rely on their phones. They play games and use productivity tools regularly. They stream videos, engage in multitasking, and use their phones for work-related activities. They get around 4–8 hours of battery backup.
 
These battery backup durations can vary depending on your device model. Models like the Pixel 6a have 4410 mAH, and the Pixel 6 Pro has 5003 mAH. So don't compare your phone with those that have a high battery capacity.
 

Tips to maximize the battery backup

 

  1. Use features like turning off WiFi and Bluetooth automatically.
     
  2. Turn off NFC and printing.
    For convenience, use QuickTile for NFC.
     
  3. Use GrapheneOS Power
    GrapheneOS offers disabling apps. This feature is beneficial for both privacy and battery backup. Some apps deserve to be disabled, like food delivery and shopping apps. They give notifications like "70% off or 90% off orders now". Disable those apps that you don't use frequently. Maybe you have a taxi app, a Google Maps app, or some other app that can help you in an emergency.
    For example, if you have multiple apps that serve the same purpose, like Organic Maps and Google Maps, and you are using organic maps to replace Google Maps but also want to use Google Maps for searching complicated places or for traffic, you can disable Google Maps and use organic maps until you need Google Maps.
     
  4. Use Data and Battery Saver
    Enable these two features for good battery backup. These features can break some apps that need to run in the background with unrestricted data, for example, Syncthing. You can always whitelist these apps from these restrictions.
     
  5. Keep apps optimized
    There are some unique scenes. Some apps are so necessary that we can't simply disable them. They keep refreshing in the background.
    For example, I want a weather app with good animation, a better UI, and more features like Rain. But it doesn't give an option for manual refreshing. So I keep this app on "restricted battery".
     
  6. Dark theme
    Don't use the usual gray-dark theme .bIt will not help you save batteries. The gray-dark theme doesn't let the screen's pixels go off. Instead of that, use a pitch-black theme. Most of the apps offer dark themes along with pure dark themes under different names.
     
  7. Screen Brightness
    Screen brightness plays a very significant role in battery consumption. Everyone has noticed it at some point. Adjust the screen brightness according to your environment. For convenience, use adaptive brightness. If you are using a pure dark theme on an OLED display, you can save so much battery power even at high screen brightness.
     
  8. Disable auto-sync
    Disable auto-sync for accounts that don't require real-time updates. Decrease the frequency of app refreshing. For example, Obtainium, Feeder, Forecastie, etc. You can set their frequency to once a day.
     
  9. Disable Google's crap
    If you have sandboxed Google Play, try limiting it as much as possible for better battery life and privacy.
    Under settings>>Apps>>Sandboxed Google Play>>Google settings, you can delete the Google advertising ID, turn off nearby sharing, disable unknown tracker alerts, and other useless crap that is not going to work because of sandboxing.
     
  10. Keeping your phone away from heat
    Heat is the biggest enemy of any electronic appliances. Make sure your phone is not heated for long periods of time.
    Don't charge your phone with your laptop if your AC is not on. Charging your phone slowly is good for the battery. But it takes so much time to charge your phone, and your phone is hot during this very long time and generates heat.
     
     
    Optional
     
  11. Disable "Secure app spawning"
    Use it at your own risk. Again, use it at your own risk. Disable this feature according to your threat model. Before reading further, I highly recommend you read this.
    Now I will tell you why I am telling you to disable this feature. This feature makes your CPU do extra processing, which requires extra power from your battery. I have no data. It is only based on assumptions.
     
    You can completely skip this if you are going to replace your battery when it degrades.
     
  12. Healthy charging habits
    Use your phone between 20% and 80%, don't use fast charging, etc. It is not usual blah-blah. Don't believe this type of article. If you don't like your phone to use between 20% and 80%, then don't follow this tip. But at least put yourself in a position where you are guiding others in the right direction. Instead of that, read this . There are already so many studies conducted and so many videos available on YouTube that show how lithium-ion batteries work.

Myths

  1. High resolution consumes so much power
    High resolutions only consume a high amount of power when your GPU needs to work harder, like when you play games at a higher resolution. Here is a video you can watch.
     
  2. Disabling animation 
    Disabling animation doesn't help you save battery. It is very hard to say how much power it saves. But it saves very little power, which gives you an extra few seconds or a minute to use your phone. I also disable animation not to save battery but to make my phone snappier.
     
     ### Problems

The only problem with the battery is unusual drain. If your idle battery drain is high or your phone is not lasting like it did two weeks ago, idle battery drain is 3%–4%. Below are some methods to solve high battery usage.
 

  • Use battery usage statistics in settings. Identify those apps that are using so much power.

  • Under developer options>>Running services, see if you can find the app that should not run.

    Warning

    Don't kill system apps like settings, GmsCompat, Keyboard, Android Services Library, etc. Look for only apps that you have installed, and they should not be running. After that, remember to turn off developer options.

  • My own method to identify high idle battery drain
    To check which apps are causing high battery drain, you have to check battery usage stats when your phone is idle. I would suggest using Accubattery usage statistics. AOSP's battery usage stats are half-baked. The best way to try this is before sleeping. Here are all the different combinations:
     
    The first day, reboot the phone and enter the password so that apps and services will autostart. Turn off Wi-Fi and mobile data. If possible, keep airplane mode on.

The second day, reboot the phone and enter the password. Wi-Fi or mobile data is on.
 
Compare the usage of both days.
 
On the third day, don't reboot the phone. Keep Wi-Fi and mobile data off.
 
_Fourth day, same setup as the third one, but keep Wi-Fi or mobile data on. _
 
Compare the usage of all four days to each other.
 
If you were unsuccessful in solving the problem, then you should wait for an update. After an update, usually battery-related problems get solved, or in extreme cases, you can ask for help from the developer.
 

Tools

I use AccuBattery and SaverTuner. Accubattery is useful to get alerts when the battery reaches to a certain percentage and for detailed battery stats. It should always run. It consumes very little power, like 2%–3% in the cycle of full charge and discharge.
Savertuner is nothing but an extreme battery-saving app. Savertuner doesn't need to run. You can delete the app after setup. Read this for further information.
 
I will edit this post if I find any problems and you people suggest something.

    • [deleted]

    Ram Use your phone between 20% and 80%, don't use fast charging, etc. It is not usual blah-blah.

    Consider reading https://akc3n.page/posts/battery-management/

    Ram turn off nearby sharing, disable unknown tracker alerts, and other useless crap that is not going to work because of sandboxing.

    Most "crap" can be made to work some way or the other

    Ram Thanks for your advice, I think you have had a good idea, and with everyone's collaboration, perhaps we could achieve a definitive guide depending on the profile of each user.

    Regarding point 6, is it possible to change the theme of the system for a purely black one?

    • Ram replied to this.

      ifman13 is it possible to change the theme of the system for a purely black one?

      Currently, there is no option for pure dark theme on system level. You have to manually go to each app's theme setting and enable it, if available.