Sony laptop will not charge more than 76%

I have a Sony Vaio SVE1511C5E with Windows 7 Home Premium 64 bit.
In the last three days, it won't charge above 76% no matter how long I give it.
The battery is about 18 months old.
The Vaio Control centre says the battery health is "Excellent" and the "Enable Battery Care Function" is not activated.

I'm not sure if I should do anything - just ignore it - or is it something that should be fixed ? And if so, how ? Presumably the battery is OK ?

Any help gratefully received !

Robert.

Hello Robert -

I have a Vaio model VPCEB47GM that's almost 8 years old. About once a month I take it off AC power and let the battery run down to about 5%. Then I let it fully charge. Once it's fully charged I enable the battery care function to 50%. I'm still on the original battery and it's still in good health.

I'd try taking the laptop off AC power and let the battery discharge. Plug it back in and see if it will charge to more than 76%. I'd also double check that the Advanced Battery Care Function didn't somehow get checked for 80% (that happened to me after a thunder storm and the Enable Battery Care Function box was unchecked. )

Thank you - I shall try that !

Robert.

I've followed marsmimar's instructions and after several hours recharging from 4%, it sticks at 79%. A 3% improvement ! The Battery Care Function is not checked. So I've just restarted the process and will see what happens.

I've had Technomage's problems before, but it has always worked finally. This seems different.

Robert.