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

Brian J. Tarricone brian at tarricone.org
Mon May 4 01:25:44 PDT 2009


On Sun, 3 May 2009 23:37:42 -0700 John Conover wrote:

> Brian J. Tarricone writes:
> > 
> > 
> > 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).
> 
> Oh, Brian, modern Li-ion chargers, (in laptops, cellphones, etc.,) are
> not trickle chargers-they are smart enough to sense charge capacity,
> and turn off the charge current after a fairly high charge rate to
> near 100% capacity; then monitor the capacity, turning on when
> necessary, to replenish charge leakage. See:
> 
>     http://www.maxim-ic.com/appnotes.cfm/an_pk/131
>     http://www.maxim-ic.com/appnotes.cfm/an_pk/663

Yes, of course, you're correct.  I must have gotten some wires crossed
in my head -- one of the main things that kills your battery (slowly)
if you leave the laptop plugged in all the time with the battery in at
the same time is heat.  That's not really all that much of a
consequence of keeping it plugged in, just that the battery is in with
the machine turned on all the time (presumably it's turned on all the
time; otherwise I don't see why you'd leave it plugged in with the
battery fully charged and the laptop turned off).

	-brian




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