Battery reported 100% but when removing AC power Notebook goes OFF

[JJBG]

Battery reported 100% but when removing AC power Notebook goes OFF. I Updated Bios, used the reset option offered. I tested the battery during boot, shows all OK, All voltage levels check as per assistant test. However, when  I unplug the AC power the notebook is switched OFF like if the battery was depleted.

[Huffer]

Run the battery diagnostic through HP Support Assistant and report the advanced results here. The simple pass fail is not very informative. How old is the laptop and what I really mean is how old is the battery? If over 2 years old then almost certain its time to replace it. 

[JJBG]

Thank you for your reply.

Yes, it has more than 2 years. However, as the status was reported OK I wanted to be sure before ordering the battery.

[Huffer]

The battery is 5 years old. It is down to 56% of the original capacity to hold power. Time for replacement.