Sign in with
Sign up | Sign in
Your question

Li-ion battery question...

Last response: in Laptops & Notebooks
Share
Anonymous
a b D Laptop
June 1, 2005 9:57:05 AM

Archived from groups: comp.sys.laptops (More info?)

I recently bought a new laptop-an uprade for an older, slower one, also
as a back-up for my desktop.

Is it better for overall battery life to use it unplugged now and then
to let it run down, then run it on AC for charging instead of just
keeping it plugged in most all of the time? Will being plugged in most
of the time affect the overall battery condition/life? I have a
Pentium M 1.5ghz @ 792mhz Centrino for the better power usage. I have
it set to warn me at 15% battery life left to plug it in...

Any answers are appreciated, thank you.

Regards,
Kerry

More about : ion battery question

Anonymous
a b D Laptop
June 1, 2005 9:09:14 PM

Archived from groups: comp.sys.laptops (More info?)

Thanks Doug, that shed some light. My slower laptop (got me into the
world of computers), a Toshiba bought used, has the same battery and
works for about 2.2 hours at most-since I bought it in 1999. The CD
player doesn't work, at 1.2 gb & 32mb memory it is the tortoise on
internet, but it still works. Laptops are great during hurricane
season when the electricity is out...

Thanks,
Kerry
Anonymous
a b D Laptop
June 2, 2005 12:15:03 AM

Archived from groups: comp.sys.laptops (More info?)

LioN batteries do not like to be cycled like nickle (your choice)

I have been told if a LiOn battery ever goes completely discharged it is
garbage. Your power supply maintains this by never allowing this to happen.

"ko57" <kowen@mobiletel.com> wrote in message
news:1117630625.380380.134900@g49g2000cwa.googlegroups.com...
> I recently bought a new laptop-an uprade for an older, slower one, also
> as a back-up for my desktop.
>
> Is it better for overall battery life to use it unplugged now and then
> to let it run down, then run it on AC for charging instead of just
> keeping it plugged in most all of the time? Will being plugged in most
> of the time affect the overall battery condition/life? I have a
> Pentium M 1.5ghz @ 792mhz Centrino for the better power usage. I have
> it set to warn me at 15% battery life left to plug it in...
>
> Any answers are appreciated, thank you.
>
> Regards,
> Kerry
>
Related resources
Anonymous
a b D Laptop
June 2, 2005 3:33:01 AM

Archived from groups: comp.sys.laptops (More info?)

"ko57" <kowen@mobiletel.com> wrote in message
news:1117630625.380380.134900@g49g2000cwa.googlegroups.com...
|I recently bought a new laptop-an uprade for an older, slower one, also
| as a back-up for my desktop.
|
| Is it better for overall battery life to use it unplugged now and then
| to let it run down, then run it on AC for charging instead of just
| keeping it plugged in most all of the time? Will being plugged in most
| of the time affect the overall battery condition/life? I have a
| Pentium M 1.5ghz @ 792mhz Centrino for the better power usage. I have
| it set to warn me at 15% battery life left to plug it in...
|
| Any answers are appreciated, thank you.
|
| Regards,
| Kerry
|

Good read on the subject.
http://www.batteryuniversity.com/parttwo-34.htm

--
Doug

I'm not an MVP a VIP nor do I have ESP.
I was just trying to help.
Please use your own best judgment before implementing any suggestions or
advice herein.
No warranty is expressed or implied.
Your mileage may vary.
See store for details. :) 

Remove shoes to E-mail.
Anonymous
a b D Laptop
June 2, 2005 3:41:17 AM

Archived from groups: comp.sys.laptops (More info?)

Li-Ion don't need to be drained like Ni-Cad or NiMH. In fact, not
having your battery in your comp but charged at like 70% is best until
you need it. Li-Ion have a set number of charge/discharge cycles before
they degrade, so not cycling it all will extend it's life.
Anonymous
a b D Laptop
June 2, 2005 3:41:07 PM

Archived from groups: comp.sys.laptops (More info?)

Thanks to all for the help, some things to think about.

Kerry
Anonymous
a b D Laptop
June 3, 2005 5:30:05 AM

Archived from groups: comp.sys.laptops (More info?)

Don't accept battery university as absolute gospel.

Lithium batteries do not need to be cycled, unlike older NiCad
batteries. But there may be some benefit in doing so occasionally (once
every few months), however, don't take them all the way down (not below
30%, if that). There seems to be a consensus that for storage, they are
best stored at a 40% to 60% charge.

What's pretty clearly best, however, is not to leave the battery in the
laptop when it's running exclusively off of ac power lines for a long
period of time.


ko57 wrote:

> Thanks Doug, that shed some light. My slower laptop (got me into the
> world of computers), a Toshiba bought used, has the same battery and
> works for about 2.2 hours at most-since I bought it in 1999. The CD
> player doesn't work, at 1.2 gb & 32mb memory it is the tortoise on
> internet, but it still works. Laptops are great during hurricane
> season when the electricity is out...
>
> Thanks,
> Kerry
>
Anonymous
a b D Laptop
June 9, 2005 7:07:53 PM

Archived from groups: comp.sys.laptops (More info?)

"Barry Watzman" <WatzmanNOSPAM@neo.rr.com> wrote in message
news:429FB2A0.4030700@neo.rr.com...
> Don't accept battery university as absolute gospel.
>
> Lithium batteries do not need to be cycled, unlike older NiCad
> batteries. But there may be some benefit in doing so occasionally (once
> every few months), however, don't take them all the way down (not below
> 30%, if that). There seems to be a consensus that for storage, they are
> best stored at a 40% to 60% charge.
>

There is no need to completely discharge the battery for life purposes.
However, many types of Li-ion battery contain a clever circuit that monitors
and reports the battery status back to the laptop. this circuit requires
periodic calibration and the only way to achieve this is to run the battery
down to the point where the laptop cuts off. (Put simply) The chip is told
this has happened and stores certain information. It then uses this to
report the charge status back to the laptop during future use. the battery
should then be fully recharged fairly soon after.

How frequently you perform this step depends on useage patterns, buit I
wouldn't perform it at less than 6 monthly intervals, but any discharge to
cut off during normal useage counts.
Anonymous
a b D Laptop
June 9, 2005 7:22:13 PM

Archived from groups: comp.sys.laptops (More info?)

<Geodanah@yahoo.com> wrote in message
news:1117694477.472965.55880@g47g2000cwa.googlegroups.com...
> Li-Ion don't need to be drained like Ni-Cad or NiMH. In fact, not
> having your battery in your comp but charged at like 70% is best until
> you need it.

40% is better.

> Li-Ion have a set number of charge/discharge cycles before
> they degrade, so not cycling it all will extend it's life.
>

Although technically correct, they actually start to degrade from the very
moment they roll off the production line. Unlike other chemistries, the
degradation is both time based and useage based. As a rule of thumb, you
lose around 18% of the starting capacity for every 100 charge/discharge
cycles (this works pro-rata so 200 half discharge charge cycles is the same
thing). In addition, a fully charged battery stored at 25 deg C will lose
around 20% of its starting capacity per year. This reduces as the state of
charge reduces (with the minimum occuring at around 40% charge), and also
reduces with temperature (5 deg C extends the time based life
substantially). 0 deg C destroys the battery, so not in the freezer thank
you very much. Discharge rate is also a factor, but as long as the original
discharge time is in excess of an hour and a half, this shouldn't be an
issue.

Individual batteries vary wildly, so examples that die within a year with
relatively low useage are not unknown, as indeed are examples that are over
12 years old that still have an almost original capacity (I have several
examples of both at home and they are from the same manufacturer (but of
different ages (the long lasting ones being older))).

Ian.
Anonymous
a b D Laptop
June 9, 2005 7:22:14 PM

Archived from groups: comp.sys.laptops (More info?)

Re: "In addition, a fully charged battery stored at 25 deg C will lose
around 20% of its starting capacity per year."

I have a very hard time accepting that. I have a couple dozen Toshiba
2487 batteries here made between 1995 and 1998, stored fully charged
(and "topped off" every few months), and they still have most of their
capacity left (they will run a laptop for about 2 hours, which is nearly
what they did when they were new). And you yourself say that you have a
number of 12-year old batteries that still have nearly their original
capacity.

There are numerous references to properly cared for lithium batteries
that are not used heavily being able to last "about" a decade, and my
own experience supports this. However, while I have always stored them
"fully charged", the consensus is clearly that storing them at 40% to
60% is better.

What's really amazing, when you think about it, is that these batteries
typically have 10 cells. Failure of one cell kills the battery. So if
you have 10 batteries that are "good" you have 120 cells. The "sample
size" is much larger than it seems.




Ye Electrik Fanne Clubbe wrote:

> <Geodanah@yahoo.com> wrote in message
> news:1117694477.472965.55880@g47g2000cwa.googlegroups.com...
>
>>Li-Ion don't need to be drained like Ni-Cad or NiMH. In fact, not
>>having your battery in your comp but charged at like 70% is best until
>>you need it.
>
>
> 40% is better.
>
>
>>Li-Ion have a set number of charge/discharge cycles before
>>they degrade, so not cycling it all will extend it's life.
>>
>
>
> Although technically correct, they actually start to degrade from the very
> moment they roll off the production line. Unlike other chemistries, the
> degradation is both time based and useage based. As a rule of thumb, you
> lose around 18% of the starting capacity for every 100 charge/discharge
> cycles (this works pro-rata so 200 half discharge charge cycles is the same
> thing). In addition, a fully charged battery stored at 25 deg C will lose
> around 20% of its starting capacity per year. This reduces as the state of
> charge reduces (with the minimum occuring at around 40% charge), and also
> reduces with temperature (5 deg C extends the time based life
> substantially). 0 deg C destroys the battery, so not in the freezer thank
> you very much. Discharge rate is also a factor, but as long as the original
> discharge time is in excess of an hour and a half, this shouldn't be an
> issue.
>
> Individual batteries vary wildly, so examples that die within a year with
> relatively low useage are not unknown, as indeed are examples that are over
> 12 years old that still have an almost original capacity (I have several
> examples of both at home and they are from the same manufacturer (but of
> different ages (the long lasting ones being older))).
>
> Ian.
>
>
>
>
!