[ltp] Thinkpad T23 Battery

[Uwe Walter]

Hi.


> There's a lot of misinformation around.

Definitely! ;)


> Other than this, I've=20
> never heard of the need to remove the battery.

Reasons are the following:

When the battery is installed and the laptop is used on AC power, the
battery is normally charged to full capacity. This contains two dangers
for the battery:

1. Heat
2. 100% charge state


1.
Heat is a big enemy for LiIon-batterys! Keep them cool (not frozen
however ;-)).
Many TPs have the opportunity that the battery is not too integrated
into the chassis, but sticks out at the back.
Furthermore, the charging circuit seems to be quite well-behaved, since
the battery does not get too hot when being charged (at least I'm not
aware of it).


2.
A high charge state is equivalent to a high level of chemical activity.
The problem with this is electrode oxidation. The higher the activity,
the more oxidation is happening inside. This is not reversible and
simply reduces the available capacity from the moment, it is
manufactured. This process is accelerated if the battery is charged to a
high degree.


This results in the following advices:

Only load the battery fully, if you plan to use it.

At other times, load it to 40% and store it away from the laptop.
See figure one of the first link below, it is really scary (20% vs. 4%
capacity loss in one year).


There are the following well-known links:
http://www.batteryuniversity.com/parttwo-34.htm
http://www.buchmann.ca/Chap10-page6.asp


The german c't magazine (which has a quite good reputation) had an
article, describing more or less the same thing:

Kraftquellen - Lithium-Ionen Akkus entmystifiziert
J=F6rg Wester
c't 17/2003
Page 170


Greeting, UW(e)