Tips to optimize the battery life of your Android Phone

Collected this from below links:
in.pcmag.com/smartphones/64040/feature/11-tips-to-boost-your-android-phones-battery-life
https://www.techrepublic.com/article/10-tips-for-improving-android-battery-life/
https://www.androidpit.com/how-to-save-battery-life
https://www.cnet.com/how-to/how-to-get-better-battery-life-on-android/
https://phandroid.com/improve-battery-life/

Battery life of your phone is almost always a pressing issue. That's why these days phone batteries have reached 4-5000mAh from the measly 500-600mAh back in the days of Symbian phones. Android is a heavy, feature-rich OS, but it sure is not battery friendly. Android was quite crappy in battery department till v4. But from then Lollypop and Marshmallow brought great changes in reigning hungry apps and bringing down overall power consumption of the Software part of the equation. These changes, coupled with modern hardware with efficient modems, and big batteries means the battery problem is almost non-existent these days. You can expect a days battery life from your android phones these days.

But batteries do degrade, and it's not always possible to get a replacement and quickly move to normal battery performance due to availability of spares and/ or non-removable batteries. So it pays to keep a look at some ways  you can optimize the battery life you already have. E.g.One of my friends is very attached to his 2014 xiaomi flagship. It will complete 4 Yrs soon and the original battery is almost dead. But my friend loves this phone, but can't get replacement battery. One - no original available and two - the phone's unibody construction makes it very difficult to even replace the original.

Anyway so lets see some ways we can all get some more battery life out of the battery we have on our Android phones:

1. Use battery Status settings page and check what's sucking most energy. You should see Screen, Android System, Android OS, Cell Standby, Play Services etc. If you see any feature or App you don't use often, get rid of it. Get rid of apps that you can do without. These apps are sucking out your battery. Kick them out!

2. Turn unnecessary hardware radios off. Modern phones have Bluetooth, WiFi, NFC, GPS etc etc. But you rarely need all activated all the time. Use notification quick toggles to shut down the ones not required. You will save a lot of battery, since when these are ON, they are almost always scanning for networks/other hardware/ nearby android devices etc. So just turn them on for work and then turn them off as soon as you are done. This will help you save quite some power. This is true especially in case of Location Service.

3. Use extra power saving mode if you have it. These days almost all phones come with some some form of power saving mode. These usually turn down CPU speed, turn off fancy animations, and put the phone in battery sipping mode. It can be automatically launched by system when battery reaches some predefined percentage like 15%. Its great for new phones, but as battery becomes old, you will start finding that it reaches 20% and then the phone will just die on you. That's LiIon battery for you. As it becomes old and worn out, it will just stop working at 20/30% as per age. So for old batteries it makes sense to just keep the power saving mode always on. That will help much with old batteries. Just ensure to go through the mode settings and change anything that may affect your favourite apps like Manual Syncing or push services etc.

4. Dump unnecessary home screens/widgets etc. All these consume precious system resources and power. If you can do without them, get rid of them. Also keep no of home screens to minimum.

5. Turn down the brightness and turn off Automatic Brightness. It's probably obvious at this point, but you'll be surprised by how much this one alone helps to improve battery life.

6. Update your apps. Applications often get updated to use less battery power, so you should make sure your apps are up to date. Even if you configured the phone for automatic updates, some apps still require that you manually install updates. Check for app updates in Google Play by hitting the menu key and going to My Apps.

7. Keep an eye on signal strength. If you're in an area with poor cellular coverage, the phone will work harder to latch onto a strong-enough signal. This has an adverse effect on battery life. There's not much you can do about this one, but keep in mind that this could be the culprit behind a seemingly weak battery; it's worth popping the phone into Airplane mode if you don't need data or voice calls.

8. Check the reviews. The battery review results vary widely between handsets, even on the same network. When choosing a phone, make sure that real world talk time is sufficient. You can't go by what the manufacturer says; reviewers have seen variances on the order of several hours of usage in both directions on a regular basis.

9. Buy a battery case or larger extended battery. Battery cases combine a hardware enclosure, which protects your phone, with an extended battery that can double your phone's endurance. You can find models compatible with popular Android phones from a variety of manufacturers.

10. Check your accounts. You may be able to save battery life by having your email or other accounts poll for new messages/data less frequently.  Each account will appear under the "Accounts" section in "Settings." "Email" will allow you to access however many email accounts are set up on your device.

11. Reduce your dependency on cloud access. Ah, the cloud, the cloud, the cloud.  It handles our backups, it syncs our documents, and it delivers us news, entertainment and information.  It also requires lots of bandwidth and makes our devices go the extra mile when everything we own data-wise resides in the cloud.
I love my Dropbox account, but it can chew up battery life on my Droid since it has to download stuff I access.  You can set it to sync only while your Android is using Wi-Fi (Dropbox, "Settings," "How to Upload") but another good option is to store all files locally if you can so you can reduce the amount of back-and-forth needed by pulling data down from the cloud.

12. Black wallpaper can increase battery. If your phone has an AMOLED screen (like most Samsung devices), use a dark-colored background. Black wallpaper can increase battery life because AMOLED screens only illuminate the colored pixels. Black pixels are unlit, so the more black pixels you have, or the more darker pixels, the less power is needed to light them up.

13. Use Doze Mode. Doze mode has been around since Android Marshmallow, but with Nougat, it's been much improved. Before, Doze would only work when the smartphone has been stationary for a while. But now, it can also work when it's being moved around (in your bag or pocket while you're on the go, for example). The screen just needs to be off to work.

14. Turn off Google hotwords. Stop your phone from always listening. Google's OK Google voice searching is a fantastic and often very functional feature. The problem is that it can wreak havoc with your battery. Especially if you don't actually use it or only use it occasionally.
Go into Google settings from your app drawer and tap Voice heading. On the next page, select OK Google detection. In this menu, the best option for battery life would be to untick all the boxes, but if you are a fan of OK Google, just tick the From the Google app box to ensure your device is only listening when you're in the Google app.

15. Turn off vibrate and haptic feedback to save battery. Switch off vibrate. Unless you really need that added awareness, turn off vibration alerts for incoming calls. It actually takes more power to vibrate your phone than it does to ring it. Turn off haptic feedback too (that buzz you get from typing on the keyboard). Sure it feels cool, but it doesn't really add anything to your experience, and it's another battery drainer.

16. Set your 'Do Not Disturb' or 'sleep' schedule. Set sleep times or blocking mode to switch off Wi-Fi and mobile data when you don't need them. If your phone is basically off limits at work, set your device to not ring, vibrate or connect to the internet while you're at work. Many phones have a Do Not Disturb setting for just this purpose.
Likewise, you can set your phone to airplane mode when you're asleep or use sleep or blocking modes to set up limits for what your phone does during certain times of the day, whether that's while you're asleep, at work or in a meeting. Cool apps such as IFTTT let you create rules that can help you save battery life too.

17. Don't fall into the auto-sync trap. Turn off auto-syncing for Google accounts. If you don't need every single Google account updated every 15 minutes, just go into Settings and Google account and turn off auto-sync for those apps you don't need constantly updated.
Some apps – like email – let you manually refresh when you launch them, rather than running multiple auto-refreshes throughout the day when you may not need them to. The same goes for Twitter, Reddit and co. Unless you need constant updates or push notifications (like for Facebook or your calendar) just sync when you actually use the app.

18. Disable location reporting and history. GPS is a huge battery hog, as it harnesses data from the phone's GPS chip, cell phone towers, and Wi-Fi hotspots to find your location. The more a phone surveys your location, the more battery it uses. And that goes beyond just Google Maps.
Location reporting and location history are two GPS-based services with somewhat unclear motives. According to a Google Help page, the services can be used in conjunction with any other Google Apps, and may be used to improve your experience.
Chances are you can probably live without them, so disable these two features by going to Settings > Location > Google Location Reporting.

19. Turn off automatic Wi-Fi scanning. It's well-known that when Wi-Fi is left enabled, more energy is used. However, on Android, even when Wi-Fi is disabled, a phone could still be searching for networks.
To make sure this isn't happening, head to Wi-Fi settings > Advanced. Here, uncheck the option for Wi-Fi scanning.
Going forward, you'll have to connect to Wi-Fi manually, but you'll get a longer battery life in return.

20. Turn off any animations to avoid wasting precious battery.
This may or may not be something that you notice often, but every time an action is performed on your device, there is an animation that also occurs. Many times we have recommended speeding up these animations to give our devices a faster feel.
However, the truth is that reducing these animations also saves you battery life. In order to reduce these animations, you'll need to access a secret menu which is found in the Settings app of every Android device.

    Open the Settings app
    Scroll down and select About phone
    Tap Software info
    Scroll down and tap Build Number 7 times
    "You are now a developer" message will appear
    Go back into the main settings and you'll see a new option: Developer options
Once you have activated this secret menu, follow the steps below to either reduce or remove the various animations on your device:

    Open Developer options
    Scroll down select Window animation and choose .5x
    Select Transition animation and choose .5x
    Select Animator duration scale and choose .5x
You won't have to restart for these changes to take effect, instead, you should immediately see the differences. The reduced animations will help you save battery life, bit by bit, although the benefits of these changes won't be reflected in your battery life right away.