Archived from groups: comp.sys.laptops (
More info?)
I don't want to repeat a thousand-post thread that occured in this
newsgroup about 15 months ago, but to summarize, the fact is that
whether they shoud or not, most laptops will apparently either
overcharge and/or overheat a battery that is left in the laptop when
it's run almost constantly on AC, resulting in the essential destruction
of the battery in 6 to 18 months (whereas, properly treated, a Li-Ion
battery can last 5 to 10 years).
There were hundreds of people who posted on this subject over a period
of several months, including quite a few with extensive experience who
design and/or service laptops (I fall into this group myself).
Quite a few people did argue that this was not the case, or perhaps more
accurately that it SHOULD not be the case. But the theoretical aspects
of the argument not withstanding, the actual real-world field experience
posted -- by hundreds of people -- was overwhelming that leaving a
battery in a laptop that's run off of ac power for long periods will
destroy the battery within 6 to 18 months, without regard to why or
whether battery chemical theory would support this.
As to the reason, again, it was felt by those with knowledge of laptops
and batteries that it was a mix of overcharging (the charger being on
24x7x365, typically, if the laptop is always plugged in) and/or
overheating (which can come from overcharging, but which can also come
from the CPU, hard drive, switching power supply and other components of
the laptop).
There is no reason to believe that Li-ion batteries have changed in the
time that they have been in use for laptops (about-10 years).
Certainly, they are different from both NiMH and NiCad batteries, and
some people don't understand those differences (the memory effect being
one of them), but I'm excluding that here.
Now what may have changed (although I do not believe that it has) is the
design of laptops and the charging circuits. However, don't exclude the
possibility that laptops have changed -- not for the better, but for the
worse. That is, they run hotter now than they used to, which is one of
the killers of batteries.
But I will make this point: If you have a laptop that is run
essentially constantly on AC, and you take out the battery, but cycle it
SOMEWHAT every 60 to 90 days (not to full discharge, but say down to
40% or so, then recharge it), then in 2 years you will still have a good
laptop battery (fact). But if you leave it in the laptop constantly, AT
BEST you will have a good laptop battery, but, based on experience, more
than likely you will have a dead battery whose replacement cost is about
$200, on average.
Now which course of action do you want to follow, because, after all, it
is your choice, your laptop, your money and your battery.
Chip Orange wrote:
> "Barry Watzman" <WatzmanNOSPAM@neo.rr.com> wrote in message
> ...
>
>>Finally, to reinforce something that's been stated here many, many times
>>(although some people still refuse to accept it), if you are running on
>>AC for long periods of time, remove the battery. If you want a UPS, get
>>a UPS, don't use the battery as your UPS; although it works great in
>>that role, a $30 UPS is far more expendable than a $200+ Lithium ion
>>battery. A Lithium ion battery can last almost a decade with proper use
>>and care (and I have some from 1997 that are still going strong). But
>>if you leave it in your computer while the computer is on AC
>>continuously, you will, in most cases, effectively destroy the battery
>>in 6 to 18 months.
>
>
>
> Could you explain why? I had a look at
http
/www.BatteryUniversity.com and
> couldn't find any support for this idea.
>
> Is it possible, if your using your own experience as the only reasoning for
> this position, that there was something different about the li-ion batteries
> manufactured more than 5 years ago?
>
> thanks.
>
> Chip
>
>
>
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