1). Enable WiFi Assist
WiFi is something that sucks a ton of battery from your iPhone. The problem is your iPhone usually desperately tries to hold onto a WiFi signal - even when it’s only got one bar. This will rapidly drain your battery. To prevent this, enable WiFi Assist on your iPhone. WiFi Assist automatically switches over to your cellular data connection when a WiFi signal gets too low. Just be warned that enabling WiFi Assist will mean you eat through more of your data plan. To enable WiFi Assist, go to Settings > Cellular and toggle the switch next to WiFi Assist to ON.
2). Enable Low Power Mode
Turning on Low Power mode will automatically turn off all but the most needed power sucking features of the iPhone when you hit 20% battery power and then even more at 10%. But many people don’t realise you can enable Low Power Mode at any time, which you should do it you want to conserve battery. To enable Low Power Mode manually, go to Settings > Battery and toggle the switch to ON next to Low Power Mode.
3). Stop your apps making those motion effects
The parallax effect is the name given to the slightly moving icons and notifications in iOS when you move your iPhone. Apple created the parallax effect to give the flat icons some depth. However, as with any process that requires movement, the graphic capabilities needed to do this eats up battery life. To disable this effect, go to Settings > General > Accessibility > Reduce Motion > and toggle the switch to ON.
4). Turn on Auto-Brightness
Increased screen brightness takes up a ton of battery power. This is because the extra light required to illuminate your screen requires a lot of energy; draining your battery faster. Screens generally require less light in darkness and more light when it’s bright outside. To have your iPhone adjust to external brightness levels automatically go to Settings > Display & Brightness > and toggle the Auto-Brightness switch to ON.
5). Disable Dynamic Backgrounds
Another motion feature in iOS is the dynamic backgrounds. These are the wallpapers that have subtle movement in them. They look cool, but that movement is eating into your precious battery life. It’s best to use a still image for your wallpaper. To get rid of the dynamic images go to Settings > Wallpaper > Choose a New Wallpaper and select a wallpaper from the “Stills” selection.
6). Reduce Screen Brightness manually
If Auto-Brightness isn’t doing it for you, you can also set the brightness levels automatically. Go to Settings > Display & Brightness > and reduce the brightness level by adjusting the slider. This will set the maximum value of screen brightness and can do a lot to saving that extra battery charge.
7). Turn Bluetooth Off
The latest iPhones have Bluetooth 4.1, otherwise known as Bluetooth Low Energy, or BLE. And while BLE uses a lot less power than earlier versions of Bluetooth it still takes up power needlessly when you leave it on and don’t intent on connecting to any Bluetooth devices. To quickly switch Bluetooth off simply swipe up from the bottom of any screen in iOS. This will bring up the Control Centre. Tap the Bluetooth button so it turns grey/ black. This disables Bluetooth.
8). Turn Off App Location Services
Location Services allows apps to know where you are based on your GPS or Wi-Fi triangulation. This is handy for a number of apps, but it drains battery power. Also, some apps request your Location Information yet it does you little good (these apps often use it for targeted ads). To save battery go to Settings > Privacy > Location Services > and toggle the switch to OFF to turn off all Location Services (not recommended) or toggle individual apps access ON or OFF.
9). Turn "Hey - Siri" Off
Siri is always working in the background as a default on iOS. She’s just sat there waiting for you to speak to her, meaning she’s always using up a little bit of battery in the background. It’s not helpful, especially if you don’t use her, it can also be annoying as sometimes Siri thinks you have said 'hey siri' then you haven't. To turn it off just head into Settings > General > Siri and then toggle the switch to OFF next to Allow "Hey Siri". You can still use Siri you can still do it with the home button.
10). Regularly close Background Apps
When you open an app on your iPhone and then go back to your home screen it can deceiving to think that you have closed the app. However, the app is still running in the background, with some apps this is helpful and required for the app to maintain its purpose, but in most cases, you don't need the app to stay open. The downside of your app staying open is that it's using processing power which drains your battery. To fully close an app so it's not still working in the background, simply go to Home > double press the Home button > place your finger on the app you would like to close and then swipe up to close the app.