Hugo Nebula presented the following explanation :
I have a problem with the level of charge from my laptop's battery.
At 100%, the battery meter is showing about 2hours 10minutes charge.
This then drops gradually at a consistent rate to about 55%, when it
suddenly drops to 7-8% (about 10-9 minutes), then consistently down to
nothing. I get about an hours charge from a full charge.

It might be that the charge calibration of the battery is out of sync,
or that the battery is nearing the end of its life.

You might try recalibrating...

Control Panel Power Options Power Schemes [Tab]...

Below the 'Running on Batteries'... set all options to never.

On the 'Alarms' tab, untick both options.

Now run the laptop on batteries until it shuts down due to the battery
being genuininly flat.

Recharge and reset all the above settings back to normal - you might
find some improvement.

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Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk