[ltp] Thinkpad T23 Battery

[Uwe Walter]

Hi Harry.


On Sa, 2005-01-22 at 08:26 +0200, Harry Popov wrote:
> > two dangers for the battery:
> > 1. Heat
> > 2. 100% charge state
> None of these is true.

No offense, Harry, but I still stick to these points.
But probably I left something unclear.

Heat and Age (=3DOxidation, increasing internal resistance) kills LiIons.


I already agreed with you in my first post, that heat does not appear to
be the biggest problem with modern T4* Thinkpads, since the battery is
located at the back. As you wrote, the heat-generating charging process
does of course stop when the battery is full, but there are laptop
models, where the battery is located somewhere inside. Inside my
Thinkpad, temperature is normally quite above 40=B0C, so this surely would
not be too healthy for a battery, being this warm all the time.


But our opinions seem to vary (*), which state of charge is recommended
for maximum lifetime. You say 100%, while I still think, such a high
state of charge increases oxidation (and kills the battery faster).

(*) But I have no problem with that. ;-)


One last thing (you already said):
If you stick to your rule and charge it to 100% you can of course keep
it stored offline longer. If one does only charge it to 50%, one must
check more regularly that it does not self-discharge too low.




Please note, I am *only* writing about LiIons. NiCd and NiMh are
different storys where different properties apply. You already described
many of them and your experiences.


> Just for information I have Toshiba 3400CT made in 1995. The last 7
> years is continiously on the main and rearly on the road. The batery
> still last for between 3 and 3.5 hours. /What it should be as new/.

NiCd, right?
I would wish, this would also be valid for LiIons.


Greetings, UW(e)