[olpc-community-support] xo laptop Battery Issue

Richard A. Smith richard at laptop.org
Sat Dec 22 10:54:33 EST 2007

Wavlngth wrote:
> Hi Richard,
> I'm having issues with my battery.  You were answering questions in the 
> olpc forum and I'm hoping you can help.
> When I received my xo laptop on Thursday I played around with it for 
> about an hour.  When I shut down, I noticed my battery life was at 79%. 
>  I don't recall what % it started at, however.  I shut the xo down and 
> about 3 hours later I powered it back up.  After about 1 minute of 
> power, my xo laptop shut itself down.  Now my xo won't work without 
> being plugged into the power outlet.  When the xo is plugged in and the 
> battery is in, the battery life shows 79% and is illuminated orange.  
> Even after a full night of charge, it is still at 79% and orange.  If I 
> unplug the xo while the battery is in and the xo is running, the xo 
> shuts down.  So clearly either my battery is dead or my xo thinks it's 
> dead or perhaps it's something else.  Any ideas?  Your help is greatly 
> appreciated.  Otherwise it's great.  I'm trying to get familiar with 
> this xo before I hand it off to my 6 year old twins on Christmas day!

First: Please don't send me mail directly without CC:ing the list. 
Otherwise my answers will not make it into the archives.  I don't scale 
well and the only way to prevent duplicates is making sure this info is 
in the list archives and makes it into the FAQs.  --Thanks.

** Double check you used 'Reply To All' so the list stays in the loop.

Ok, Now lets try to see what's up with your battery.  The laptop ships 
with a utility called 'olpc-logbat' which will monitor some of the 
battery parameters.

Do the following:  Note the commands are inside the ' ' you don't type 
the quotes.  <hit enter> means press the Enter key.

Plug up your XO with the AC external power adapter.

Boot sugar and startup the terminal app.  When you get to a prompt that 
looks similar to this:

[olpc at xo-0C-F0-8B ~]$


'su -' <hit enter>

This will make you the root user.  your prompt should look something like:


Now type:

'olpc-logbat' <hit enter>

Now the system is logging battery info every 10 seconds and writing it 
to the terminal.  Each line consists of 6 numbers and 2 words all 
seperated by commas like:


The key for these lines are:
(each line corresponds to a column)

date in seconds,
charge %,
Bat Voltage in uV,
Bat Current in uA,
Bat Temp,
Bat charging status,
Bay level status,

I'm interested in what is happening with the 2nd, 3rd, 4th numbers.

Now while olpc-logbat is running please remove the battery and wait 10 
seconds for a sample.  You should see a lot of stuff about "No such 
device"  This is normal.  Now plug the battery back in and watch what 
happens with the 2nd, 3rd, and 4th numbers.  In particular whats going 
on with the 4th number as thats the battery charge current.

olpc-logbat will store all this info into a new logfile every time you 
run the script.  This file is stored in the /root directory and is called:


If you know how to mount a usb disk manually (or you have your XO 
networked) then you can copy that file on to the disk and send it to me. 
  But just watching what the numbers are doing and reporting that back 
will work as well.

Richard Smith  <richard at laptop.org>
One Laptop Per Child

More information about the community-support mailing list