low battery shutdown

Paul Fox pgf at laptop.org
Mon Feb 22 09:37:54 EST 2016


martin wrote:
 > On Mon, Feb 22, 2016 at 9:12 AM, <peter at easthope.ca> wrote:
 > 
 > > When my XO 1.5 shows about 33% charge, the system shuts
 > > down with no warning.  This is normal behaviour?
 > 
 > 
 > Not normal behaviour. It is consistent with a battery that has reached the
 > end of its usable/reliable life _or_ a battery that has unbalanced cells.

that sounds right.

it might (or might not be) interesting to look at the power logs kept
in /home/olpc/power_logs (i think that's the name).  there might be an
indication there as to why the system is shutting down early.

the system will shut down based on the result of the function
"low_battery" in /sbin/powerd (powerd is a script).  that function
checks whether the capacity is reported as less than 1%, or the voltage
as less than 5.7V.  if you can't swap or rebalance your battery, you
might be able to play with the contents of that function to get a
clean shutdown earlier.

paul

 > 
 > Note that this happens on almost every battery-powered device, not only
 > XOs, when batteries get old or their cells unbalanced.
 > 
 > IIRC wiki has instructions on how to try to rebalance batteries.
 > 
 > 
 > 
 > 
 > m
 > -- 
 >  martin.langhoff at gmail.com
 >  -  ask interesting questions
 >  - don't get distracted with shiny stuff  - working code first
 >  ~ http://docs.moodle.org/en/User:Martin_Langhoff
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=---------------------
 paul fox, pgf at laptop.org



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