Resetting laptop battery % in Vista

[Carenza]

The % left on my laptop battery seems to be out. I can start at 100%, leave the laptop on for 2 hours plus and the % drops to about 50%ish then laptop justs powers off, sudden swith off not a 'nice' hibernate / sleep.

The battery seems to be lasting the correct amout of time its just the % count that is wrong.

[Train]

Time to calibrate then.
http://h20239.www2.hp.com/techcenter...attery_max.htm

Makes the battery last long, well worth the trouble!

[Carenza]

As a matter of interest, when a laptop battery start to lose its charge does it go gradual and just not last as long as it used to or is it like my case a sudden switch off?

[Train]

Mine shutdown at about 8%.

Had to do one about weekly until I got it down to there though.

Run it until it shutdown, then waited about a half hour longer before plugging the power in. Had to repeat it again unti;l I got it where I wanted.

Salvaged it.
Hope that helps

[Carenza]

I was trying the instructions above and notied somehting strange.

I let the battery run down last night and as now seems to be happening the laptop switched off completley.

I plugged it in this morning to charge and the light on the front of the laptop for the power came on but after about 30 mins it started to flash which according to the manual means low battery.

I switched on the laptop and the battery symbol in the status bar said 70%, plugged in, NOT charging. I unplugged and pluged in the power, the light on the front now stayed on and the battery changed to 58%, plugged in, charging.

I know batteries go off after some time and mine is about 14 months old (In Fedora Linux it reports the battery capacity is 82% and from what I have read that seems about right for a 1 year old battery).

If my battery was working as normal and going from 100-0% but only lasting 80% of the time it used to then I would understand that but what seems to be happening is that the battery is being charged up from between completely empty to 50% in terms of the actual charge in it BUT the system thinks it is going between 50% and 100% so when I use it and it drops to 50% and I get the amount if time I am expecting for about 50% of the battery but then it switches off because the battery is actually empty.

I know this sounds of a classic description of 'memory effect' but I thought that only happened to older NiCad batteries.

[Train]

Yes that happened with the Nicad batteries.

Try a second discharge / recharge.

I followed the instructions and my battery is almost 3 years old and is working fine.