Reasons why your Android battery drains quickly and how to prevent it.

There are several potential causes if your Android device's battery is draining quickly:

• Having multiple apps running simultaneously - Apps consume battery when in use. Running several apps at once or having lots of apps running in the background can increase battery drain.
• Screen brightness set to max- Screen brightness impacts power consumption, so keeping it maxed out all the time could make your battery drain faster. Adjust it according to the environment - bright when it's sunny, dim when it's dark.
• Device getting hot- High temperatures can sometimes lead to faster battery drain. Potential causes include using it in hot environments and doing processor-intensive work. Running multiple apps simultaneously or using demanding apps can heat up your device.
• Not using the included power adapter- Using a non-original power adapter could lead to improper voltage regulation and make your device hot. If using a third-party adapter, check it's compatible with your device specs.

Here are some ways to potentially reduce battery drain on your Android device:
*Note: Can vary based on Android version and device type.

• Use Battery Saver or Extreme Battery Saver mode - Battery Saver and power saving modes help conserve battery life. Availability varies across devices - check your manufacturer's website for details.

When enabled, Battery Saver and Extreme Battery Saver modes may pause most apps, turn off features and slow processes, which may include:

• Only update app content (email, news, etc) when opened.
• Stop location services when screen is off.
• Prevent apps running in background unless Battery Optimization is turned off.
• Not respond to "OK Google" hands-free commands.
• Turn on Dark theme.
• Delay notifications.
• Turn off always-on display.
• Disable Active Edge squeeze activation on Pixel phones.
• Turn off car crash detection on Pixel 3, 4 & later.
• Turn off Motion Sense on Pixel 4.
• Turn off Smooth Display on Pixel 4 & later.
• Switch 5G Pixel phones to 4G.
• Limit internet connectivity and location access - Minimising mobile data, WiFi, Bluetooth, location services when not needed can help conserve battery. Turn on Airplane mode when mobile data isn't required. Also avoid battery draining apps like cameras and games. Don't keep lots of apps running in the background.
• Use dark colour themes - Using dark mode/theme on your device and apps can reduce battery drain, if available. Helpful for avoiding bright light stimulus at night and sleep concerns. To enable:
• Open Settings app.
• Tap Display.
• Turn Dark theme on or off.

If the battery seems to drain very fast even after following the tips above, there could be an issue with your Android device. Try:
*Varies by Android version and device.

• Restart your phone - Restarting can sometimes fix battery related problems. Long press the power button and tap Restart in the prompt. Restart method varies across devices - check user manual or manufacturer support pages.
• Update Android - Updating to the latest Android version can potentially fix battery issues. To update:
• Open Settings app.
• Tap System > System update at the bottom. Tap Device info first if needed.Follow onscreen steps for update status and prompts.
  • Update apps - App updates can resolve battery drain bugs. To update apps:
  • Open the Google Play Store app.
  • Tap profile icon at top right.
  • Tap Manage apps & devices.
  • Update all or specific apps under ‘Updates available’.

If these steps don't help, consider replacing the battery. Hardware issues like degradation may require a new resolution. Factory resetting can also fix persistent trouble - backup data first.
If battery problems continue despite these fixes, check with your device manufacturer or purchase retailer for further support.
Review your usage patterns, settings and config when the Android battery seems to drain fast. Fixing issues one by one could help resolve problems. If not, you may consider upgrading your device to a newer model with higher battery capacity.

References:

Extend the battery life of your Android device | Android Help
Use dark color patterns on your Android smartphone | Android Help
Use battery saver on your Pixel phone | Pixel Phone Help