iphone x battery stuck at 3%

Have you tried to Force ReStart your iPhone and then checked to see whether the issue continues? If NOT then please see below-

Try and Force Restart your iPhone exactly as shown below and see whether that resolves the issue:

• Press and quickly release Volume UP button
• Press and quickly release Volume DOWN button
• Press and Hold the SIDE button until an Apple logo appears then release the Side button (Can take up to 20 seconds. DO NOT release Side Button when invited to Slide Power OFF).

Axel F.

Protect & Prolong life of your iPhone's Battery:

1. About the battery usage on your iPhone, iPad, and iPod touch ...
2. Batteries - Maximising Performance - Apple (IN)
3. iPhone Battery and Performance

Try some of these options too.

1. Avoid Screen Mirroring
2. Put on Low Power Mode
3. Put Auto Lock On (1 min):- with low power mode it will be 30 Sec
4. Put Auto Answer Off
5. Disable Push notifications for apps you do not use often
6. Keep your iPhone Face down to prevent notifications to light up screen
7. Enable Auto Brightness:- Settings > General > Accessibility > Display Accommodations > Auto-Brightness [Enable]
8. Manually lower brightness from Control Center
9. If you Want to watch continuous Video. Stream it on TV or a Monitor
10. Don't force close apps; Apps which are not on frontend screen are paused by the system to save energy. Apps require more energy to re-launch. Apps which are open in the background use large memory is a myth and quitting them is counterproductive
11. Location services to be allowed only while using the app
12. Set your iPhone to fetch email and calendar data from internet less frequently
13. Turning off Background App Refresh 
14. Charge before it drops below 20-30%
15. Try connecting to trusted Wifi where ever available in stead of Cellular
16. Enable Airplane mode in areas with bad cellular and wifi coverage. Your phone keeps trying for reconnection with the missing / weak network. This uses lot of energy
17. Switch off Wifi & Bluetooth while in Roaming or Not in Range
18. Enable "Wifi Assist" : Settings > Cellular or Settings > Mobile Data > Wi-Fi Assist [Enable]
19. Periodically Check your Battery Health (Settings > Battery > Battery Health)

If Optimized Battery Charging doesn't activate

Optimized charging is designed to engage only in locations where you spend the most time, such as your home and place of work. The feature doesn't engage when your usage habits are more variable, such as when you travel. Because of this, some location settings must be enabled for Optimized Battery Charging to activate. None of the location information used for this feature is sent to Apple.

Here are a list of settings that must be enabled:

• Settings > Privacy > Location Services > Location Services.
• Settings > Privacy > Location Services > System Services > System Customization.
• Settings > Privacy > Location Services > System Services > Significant Locations > Significant Locations.

Have your iPhone examined at the Apple Store or at an Apple Authorized Service Center. If they are not open then please contact ➔ Apple Support

Axel F.