To determine why laptop battery may not be staying charged:

1. Check your charging cable to ensure it is securely connected correctly to the laptop.
2. Check to make sure the laptop is actually charging while connected.
3. If the laptop is not charging, try a different charging cable, or test the existing cable on a different device—to see if the issue is with the cable or the laptop.
4. If still nothing, use a voltmeter to check whether the laptop is receiving the correct power, or take the laptop into a repair shop for professional assistance.