[svlug] question - my laptop won't charge to 100% even though plugged in and using AC power

James Sparenberg james at linuxrebel.org
Sun May 3 22:34:56 PDT 2009

Brian J. Tarricone wrote:
> On Sun, 03 May 2009 18:47:08 -0700 Alan Denney wrote:
>> On Sun, 3 May 2009 17:10:22 -0700, Jeff
>> <jeff.lists.nov.2006 at gmail.com> wrote:
>>> If you do not use the battery, you practically do no need it. I
>>> would remove the battery completely if you do not use it... In your
>>> case I would order a new battery and save it for when I travel or
>>> other times a battery is needed.
>> "Need"?  Maybe not, but it's a darn good thing to have in place  if
>> the power goes out in the middle of an unsaved session, even if just
>> becomes some idjit kicked the plug out or stepped on the power switch
>> for the power strip.
> True, but leaving Li ion batteries plugged in all the time is one of
> the main things that reduces their life (it's basically the increased
> temperature that does it).
>> It's probably at least partially salvageable by repeated drawing
>> downs and full recharges.
> Nope, not in the least.  That may have been true of NiCad and possibly
> NiMH batteries, but you'll get the exact opposite out of Li ion
> batteries.  Repeated full discharges + full charges are also what
> reduces their life.  Li ion batteries don't have the "memory" that
> other types do that can sometimes be fixed by "refreshing" them in this
> manner.  Doing full discharge/charge cycles will actually make the
> battery worse.
> Also, they lose capacity just by existing, even if you don't use them.
> Assuming you aren't using them, the best thing to do is to store it
> around 40% charged in a cold place.  Of course, that often defeats the
> purpose of having a laptop :-P
>> Best-value source for replacement batteries:  eBay.
> Yep, definitely.
> 	-brian
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One thing I noticed was that when you ran cat on the /proc/acpi....... 
section it stated that charging was in the state 'unknown'.  I can 
duplicate that on my older laptop by putting back into it a known bad 
battery (in fact I can duplicate all of your symptoms.) I even get the 
flashing amber light with it.  Once my good battery goes in I get a 
steady light and either "charging" or 'discharging' indicated. 

Addtionally I'm one who says go for e-bay on batteries, especially for 
older laptops.  For my acer 50 bucks got me a new battery with 2x the mw 
and a lot more lifetime, Where Acer wanted 110 for the original. 

Finally for caring for the li-ion battery.  This is generally a reliable 
site. http://www.batteryuniversity.com/parttwo-34.htm


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