Thanks for the workarounds. There have been lots of new comments, so I
want to repeat the summary of what we think the root of the problem is.

"surreal wrote on 2009-11-18:  #11

I have done some research on this problem and come across an informative 
discussion on this problem on a Debian-related mailing list:
http://www.mail-archive.com/[email protected]/msg01135.html
What I got from this is:
The Eee pc's battery does not adhere to ACPI standards in reporting its 
capacity, returning a percentage in a field which is specified as having the 
unit mAh. Linux (ACPI driver, I guess) exports the percentage value of capacity 
in mAh in /proc/acpi/battery (and possibly elsewhere), which leads into 
problems in anything that uses it.
So where should this be fixed? Given that this has slim chance of happening in 
Eee pc's BIOS and no chance of everyone even upgrading to that unlikely new 
BIOS version, I would say the next best place would be just one step up the 
ladder -- in Linux ACPI driver -- because if this would be fixed (only) in 
devicekit-power, other processes that don't rely on dk-p, e.g. manually cat'ing 
/proc/acpi/battery/BAT0/info, would still return erroneous results."

Bottom line: some eee pcs does not report battery information in the
proper format. The correct place to fix this is in the eee pc bios
(which Asus has done in newer models). Make sure your BIOS is up to
date. The battery information is sent by the EC (embedded controller),
and I saw many EC firmware updates in Asus's official BIOS updates. If
the BIOS updates do not work, the next best place is in the Linux Kernel
ACPI driver. Reading through mailing list archives, it appears that the
hardware in earlier eee pcs had lots of ACPI bugs. For example, see [1].

[1]
http://wiki.debian.org/DebianEeePC/HowTo/Configure#Board.2CBIOS.2CACPI.28eeepclaptop.29
On some models, the battery info is not very precise (jumps from 10% to
100%, no rate information, etc.). Apparently, this is normal. It appears
that the userspace battery utilities expect the battery to report mAh,
but in fact it reports percentage. This is either a bug in the battery
firmware or a bug in the BIOS; it is known to be fixed with newer BIOS
versions and kernels ≥ 2.6.25.

-- 
power manager reports 1% battery even though it is full on Asus Eee PC netbook
https://bugs.launchpad.net/bugs/403303
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