Inspiron 5570 battery

That doesn't make sense. The battery is not used when the adapter is plugged in. If the battery is 18 months to 2 yrs old it might be failing but maybe the adapter is having problems. Yes you should be able to remove the battery and use the adapter alone until you can replace the battery. However--Maybe the adapter is bad. Check the bios to see if there is a message about the adapter not being recognized. You might need a new adapter.

Hello, I have the same problem on my Dell Inspiron 5570. It gives me message of my adapter not being of the proper wattage and does not charge the battery. My adapter is exactly the same which is required by the system  but i bought another adapter which is getting the same message. On running diagnostics I received a message about the Battery " The battery is reaching the end of its usable life" but it doesn't say that the battery is dead. I would assume that the battery is dead as the system stays ON while its connected to the AC outlet but shuts down immediately it is disconnected. 

Am I getting to the right decision ?? Do I need a new battery ?? 

Welcome to the Dell Community  @NasirU 

Sounds like it needs to be replaced.

https://www.parts-people.com/index.php?action=item&id=30294

Check compatibility.

Best regards,

U2