Battery charge reported incorrectly

I'm having some problems with my laptop battery, more specifically the discrepancy between reported and actual charge level. (The laptop in question is a Thinkpad T60, but I thought I'd post my question here, because I guess these kinds of problems arent only Thinkpad related. I apologize if I should have posted on the IBM/Lenovo section.)

I've tried two different batteries, both used, and they all have the same problem that there is actually much more charge left than any software reports. For example, the maximum charge with the current battery is supposed to be only something like 13 Wh, but the laptop stays on long after the meter has reached 0 %. Also, the charge level can drop instantly, say, from 50 % to 1 %.

Calibrating the battery only makes things worse. Initially the reported maximum capacity was 38 Wh, but the charge meter behaviour was totally unreliable, so I decided to calibrate. And now it's only 13 Wh. Still, I can use the laptop for about 2 hours, so it has to be more than 13 Wh.

The reason I haven't tried a new battery is that if this is a defect with the laptop itself, then I wouldn't want to invest in a new battery at the moment.

Is it common for a battery to be in good condition otherwise, but to report the charge left totally wrong? Or is it more probably that there is something wrong with the laptop itself?

 

Well it's usually the battery that reports it's charge to the laptop. So when you calibrate it's actually trying to get an accurate reading not making it worse. It was always less than X amount and calibrating brings it down to where it should have been all along. The batteries themselves have the circuitry inside to tell the laptop it's current charge so buying a new battery is where you should start.

 

The battery charge left can often be wrong, but usually recalibrating should solve that. If recalibrating doesn't, then there could be something wrong with the gauge itself, which could be a little dangerous, as if the gauge can't tell when the battery is fully charged or fully discharged, then it might either let the battery discharge below safe levels (which means you'll end up with a dead battery that can no longer be charged), or let the battery overcharge (which means you end up with a dead battery, or, in extreme cases where the protective measures fail, an explosion or fire). Are you using a utility to calibrate, or are you manually taking it all the way down until it shuts off entirely?

 

Thanks for your answers.

I've tried both manual calibration and application based. The application based method is in Lenovo's Battery Managemet software. There's a button titled "battery gauge reset".

The odd thing is that when calibrating with the program the calibration never ends. It charges, discharges and recharges the battery, but it never finishes this. If I try to quit the program it says that the calibration is not finished yet.

I've let it run for 24 hours, all powersaving modes off and I haven't used the computer during calibration. However it just won't ever say that the calibration is finished.

Is this gauge inside the battery itself?

 

Yes, the gauge is in the battery itself, so it sounds as if something is wrong with the batteries. There wouldn't happen to be anyone around with a T60 that you could have test your batteries for you, is there? Where did you get them from?