Thinkpads Forum

HI ALL!
This TP770ed hasn't been used for years, but now I started to use it again. Of course the battery was dead, but we had a spare battery, which has never been used. Now we inserted it, it started to charge, when it was fully charged, we unplugged the adapter. It seemed to work perfectly, but when it reached 85%, it dropped suddenly to 0 .
We have made some charge-discharge circles, but it didn't get any better.
Well the battery pack is not orginal IBM, it is Energy+...
I've read that probably the microcontroller in the battery does not let fully discharge, because it shuts down earlier. And if I put some paper to the pins which connect that microcontroller to the PC, the battery would probably fully discharge.
So does anybody have any experience?
Which of the 5 pins are connected to the microcontroller?

Thanks for Your help!

You can modify the settings in Windows (power management) so that the laptop does not automatically shut down , hibernate or suspend. Then you can discharge the battery completely because if the battery is really empty the laptop will immediately switch off. It can be possible that it will work a long time (e. g. one hour) with the counter at 0 % until the pack is REALLY empty. In many cases the counter is at 0% much too early.