The battery level of my ThinkPad T420s has dropped to 10% within a few minutes for a few weeks. Since this is the "critical battery condition" according to the standard setting, I always preferred to connect the charging cable directly.
Yesterday I tried to recalibrate the battery. So I set the critical battery level to 3%. After only a few minutes, the battery level had dropped from 100 to 8%. According to the display, one minute should remain. Then the laptop stayed on for an hour and a half - at the brightest brightness level and a running YouTube video.
Can I do something so that the battery level indicator shows something reasonable again?
The percentage battery display is determined from the voltage curve of the battery
If the battery is bad / old, the voltage drops very heavily under load and thus immediately reaches the low percentage value
What (limited) helps to prevent such jumps is to re-calibrate the voltage curve for the bad battery.
However, if the battery constantly keeps the low voltage until it is finally empty, it is also difficult to estimate the further course
How did you try to calibrate? Often a few cycles of fully discharging and charging help, preferably without interruption
I only find it confusing that he stays there for an hour and a half.
Here's how I calibrated it:
Critical condition set to 3%
Battery charged to 100%
then let him unload
after he got out, went into the BIOS and let him unload from there again
several hours later it was charged for 10 hours (without using it)
But yes, I'm still in the process of unloading it for the next calibration…
As I said, the percentage display is calculated based on the voltage curve
If the voltage now remains fairly constant at low voltage due to the exhausted battery, the percentage display does not change.
When the battery is empty, the voltage suddenly drops rapidly and the PC switches off
