kpowersave stuck at battery charging

Mikkel L. Ellertson mikkel at
Wed Jan 2 07:06:52 PST 2008

Andrey Borzenkov wrote:
> On Wednesday 02 January 2008, Alexey Starikovskiy wrote:
>> It could be your case. Please try to discharge battery to, say, 89% and 
>> then check if it charges to the
>> 100%.
> That is exactly the question - how do you compute 100%? As far as I can tell the 
> only possibility is - when battery stops charging. At this point you have to 
> assume battery is fully charged.
There is a chip inside the battery that reports the state of the
battery. This is where you get the time left on the battery as well.
But in order for the chip to properly reflect the state of an aging
battery, you have to let it recalibrate itself every so often. You
would have to look in your laptop manual, but it isn't unusual for
them to recommend discharging to somewhere between 5% and 10% and
then doing a full recharge. This is because Li-Ion batteries do not
show a voltage drop until then end of the discharge cycle, so
monitoring the discharge is the only way to predict how much battery
charge is left.


From the numbers, the battery was designed to have 38880000 full
charge. The smart chip has calculated that 37530000 should be full
charge now, and that the battery is only at 35640000. Running a
discharge/charge cycle should reset the POWER_SUPPLY_ENERGY_FULL to
reflect the current battery capabilities.

Without the chip in the battery, your status would be limited to
charging, low, and OK. If current is flowing into the battery, it is
charging. It the voltage level is dropping, it is low. Otherwise it
is OK.


  Do not meddle in the affairs of dragons,
for thou art crunchy and taste good with Ketchup!

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