Random Shutdowns when charger not plugged in

[Aaden]

If i am using my laptop when not plugged in and battery is not very low,enough to power it up for 20mins it will just shutdown no notifications,no BSOD .i f turn it on sometimes it will turn while booting it will shutdown,or sometimes it will give no response at all and when i plug in charger it just starts working as if nothing happened...

 

[chromic]

broken battery or something?