[ltp] Thinkpad T23 Battery

[Harry Popov]

Hi Martin,

Nothing personal. Being a newbe to Linux I learned a lot from this
list. As I have extream pracice with all kind of bateries just wrote
my opinion.

On Sat, 22 Jan 2005 09:44:23 +0100
Martin Steigerwald <Martin@lichtvoll.de> wrote:

> Hello Harry,
> 
> its astonishing how many different oppinions are available on this
> topic.
> 
> I read an article in c't magazin (http://www.heise.de) where the
> author claims the following:
> 
> 1) leaving a battery in the laptop that is connected via AC
> connerctor causes it to get worse early since the laptop often
> recharges the battery back to 100%. The author explains that each
> recharge cycle, even when it only recharges a few percent of
> capacity, counts as a full recharge cycle. He also states that a
> notebook battery can do about 1000 recharge cycles.
> 
> 2) It is not good to store a battery which is not in use charged
> at 100%. Better would be using 80% and not below 50%. Thus when
> you store a battery for years you would better check that it
> doesn't go below 50% charge. He also says it doesn't help putting
> a battery into the refrigerator, but it should be kept below usual
> room temperature when storing it for a longer time. I do not know
> his exact explains, but it goes along the way that high charge and
> high temperate are not good for battery health.
> 

I almost agree with this. The temperature "bellow usual room
temperature" is actually 7C. THis is the lower shelf in a usual
kitchen ice-box. Using 80% capacity before storing means only less
time you could keep it aside of computer safely. Unfortunately every
batery has so called internal resistance which acts as a load and is
discharging the batery all the time. Keeping this resistance low is
one of the main technology tasks but unfortunately it is still well
over zero. I could explain that quite scientific if I should use
Bulgarian but as you see my English is quite limited.

>From my 33 years practice, which is aside computers and mostly
radiostations etc, I know that for Litium bateries it is always
better for the baterry to be under some kind of cicling /charge
disscharge/ which is the case with notebooks bateries. While this is
true with litiums, it is another jobs with NiCads. They formed so
called memory if are constantly discharged to the same level and
this level is not 100% discharge. Which actually is the case when a
notebook is connected to the mains with batery in. Perhaps this was
what the author of the above ment without mentioning that.

Just imagine a NiCad charged to 100% and when discharged a lill the
electronic charger is recharging up to 100% and this repeats many
times. /no rule how many times/ Then Nicads formed a memory and if
you want to use it on the road you understand that it is usable less
time than expected. Couse it has formed low level memory and can not
be dishcharged below this level although it should.

Actually if this happened in a notebook the foult is the engeneer of
the notebook. The capable one know this problem and before charging
a NiCad they first fully discharge it.

It is quite natural if you bye a new NiCad and it shorted quicker
than your old one. That means it was not kept according a rule on
the shelf. They should keep it unformed./means never put on the
charger/ And as most of the modern bateries a factory formed, they
should be kept charged in the ice-box. Under these condition it can
stay up to 5 /five/ years waiting the byer. Unfortunately most of
the sellers did not even hear for this and sell faulty baterys.

I know how to brake such memory in NiCad batery. Generally speaking
you have to charge/discharge at a very heavy condition. It is
dangerous so I do not recommend that for unexperience one. Perhaps
Google has a lot of information on this topic.

My advice is bye a litium bateries. And if you bought a NiCad and it
has short capacity feeding the notebook then make several one after
another cicles. Discharge it at heavy load. /ex: compile a kernel
even if you do not need that/ and then charge on the lightest
possible way./ My Toshiba charges for 8 hours when the comp is
switched off and much faster when it is on/. After first discharge
let the batery stay 14 hours under charging though the indicator say
it is ready.


> > Second good way to keep the long life of not used batery is to
> > be charged at 100% and stay under tiny charging condition. It
> > can be kept for age in this way. Exactly what is happening if
> > the notebook is on the mains. This condition is not true only if
> > the charging unit of the computer is broken.
> 

Shoulsd explain that this is for litium bateries. Just forget that
NiCads are still on in the shops...sri.

> On the mains? What does that mean? My english leaves me here. Does
> it mean to be connected with AC connector? That would be exactly
> the condition the author of that c't article doesn't recommend.

Yes. /see above/. Not true for NiCads. My foult. Have to be more
precise when explaining. Thanks for the remark, Martin.

> 
> Regards,
> -- 
> Martin 'Helios' Steigerwald - http://www.Lichtvoll.de
 
Regards,
Harry Popov