Hi,
Please do try these troubleshooting steps that may help.
- Right click on the battery icon on the bottom right hand corner and select Power Options.
- Click on "Change plan settings then "Change advanced power settings".
- Now once Power Options is open, expand Battery and Critical battery action, set both On battery and Plugged in to "Do nothing".
- Expand Critical battery level then set both On Battery and Plugged in to 5% then click Apply and OK.
- Once done, unplug your laptop from its charger again and see if the same problem will persist or not.
- If the same problem will persist do test your AC adapter, remove the battery off the laptop then boot it up with just the AC adapter connected. If it stays on with just the AC adapter that means it's working properly and the battery is already faulty.
- Do also try charging the battery of the laptop using a different AC adapter and see if it will stay on when it's fully charge and the charger unplugged.