laptop battery shuts down after 3 minutes but tests fully charges after shutdown

[joyous1844]

my hp battery shows fully charged but will only run for 4 minutes. tests fully charged at 16,8 volts. battery has 8 li-ion 18650 which test at 4.02 volts each. any suggestions

 

[popatim]

Voltage is not representative of the charge state.
I'm not saying it isn't fully charged, just that this isn't how you tell.