battery problem - Ideapad Z570 [ Edited ]

[pritam79]

I have been using a Lenovo Ideapad Z570 since Sept’11. Since I use it with power supply from the mains at most times, I choose the ‘best battery health’ option of the Energy Management tool that comes with the drivers CD. This limits the battery charge to 50% which is the better option for ensuring a longer battery lifetime. But two days back I faced something unusual that had never happened before. That is regardless of whichever option I choose (‘best battery health’ or ‘optimize for battery runtime’), running on a 95% charged battery without AC power supply results in the charge going down gradually from 95% down to somewhere around 50% to 40% (As expected), but once the charge goes below 50%, 45% or 40%, suddenly the charge goes down to 7% in a second with a warning message asking to turn on the mains power supply or else it will shut down. Now the problem is that “on running the laptop on battery it gives a backup from any maximum point (say 70%, 80%, 90% charge etc), only down to 50%, 45% and 40%, whereas the battery should have given further backup below 50%, 45% and 40% and further down (which I m not getting)”. Please help me in this regard

Moderator Note: Added IdeaPad's model.

[Duck3]

Any option in Energy Management for Calibrate Battery
or similar?

[pritam79]

Energy Management has two options 'Best battery health' which charges the battery to just 50% thereby ensuring its longer lifetime and 'longest battery runtime' which charges the battery to 100% giving full backup thereby reducing its lifetime. But whichever mode I select, there is no battery backup after it goes below 40%.

[Duck3]

Here is how I would calibrate battery:

Fully charge battery, then unplug.
When battery low warning shows, restart computer.
Enter BIOS setup. (Press F2 key at Lenovo screen.)
Let laptop sit until it shuts off, and note how long it runs.

(If you let it run until it shuts down in Windows,
you risk file corruption.)

Plug in and recharge.
See how long it runs on battery.

[pritam79]

i have been using a wireless USB mouse 24x7 since the day i bought the laptop. Also i use a USB device (a mobile broadband service) for internet purpose. Could these be of any concern for the battery problem, for people say that too much use of the USB port degrdes the battery.

[sajad2000uk]

Open the Lenovo energy management, and where you have the options for Optimize for battery health or battery run time, at the bottom it says 

Battery Gauge Reset

Start.

click it and do the on screen instructions.

[pritam79]

What is the purpose of the gauge test?

[Duck3]

That is the battery calibration. Try it and post results.

Thanks sajad2000uk!

[pritam79]

I performed the Battery Gauge reset function, and during the process the battery got charged to 99% and gradually it went down to 2%. The mains were ON during the entire process. When it reached 2%, it said that the process is over, and automatically started charging the battery again. I have selectd the "optimise for battery runtime" now and hence its still chharging. But i fail to understand as to what purpose did the whole process serve as it was just a charging and discharging process.

[sajad2000uk]

your laptop has reset the values it has for 1% battery and 100% battery charge. the calibration tool will check the battery like it's a new battery to work out what kind of state the battery is in so it can give you the correct value's  based on the results it just got.