Hi,
Here are some troubleshooting steps that may help identifying which one is faulty the batter or the AC adapter.
- First do a hard reboot, remove the battery and unplug the AC adapter then press and hold the power button for 20 seconds then boot it back up. Do test it again if it will charge or not after booting up.
- If it doesn't work remove the battery again and boot it up with just the AC adapter and see if it will stay on.
- If the laptop will stay on with just the AC adapter and without the battery that means the charger is working properly.
- While the laptop is on put the battery back in then see if it will charge or not.
- If it doesn't work that means the battery is faulty already unfortunately.
- Do also try a different AC adapter and see if the same problem will persist or not.