Hi,

My mom recently got a computer and I have been helping her with it.

I read in the instruction manual that you should never charge the
battery for longer than the required time because if you keep charging
the battery when it is full the battery will be damaged.

When the computer is turned off and the power cord is connected the
computer takes four hours to charge.

When the computer is turned on and the power cord is connected the
battery will take 12 hours to charnge.

My questions is this: When the computer is connected to the power cord
and the battery is full, won't the battery be damaged from over
charging? Is there some way to stop the battery from charging when the
power cord is plugged in? My dad think that we may have to remove the
battery when we use the power cord to run the computer.

Thanks for any help,
Andrew

Re: "I read in the instruction manual that you should never charge the
battery for longer than the required time because if you keep charging
the battery when it is full the battery will be damaged."

I have never seen that stated in a manual, and it should not be true ...
but at some level, it is. We know that if you leave a battery in a
laptop that is continually powered from AC, over time it will be
damaged. But the damage is very slow and takes a LONG time to occur (6
months to 2 years). It's not normally a problem in terms of casual use.
There should be no problem leaving a battery in for days or weeks at a
time, but if the laptop is always plugged in, then you are better off
removing the battery, or it will be damaged (very, very slowly, over
months or years, not days or weeks).

The charging behavior that you are seeing is normal. It should take
longer (a lot longer) to charge when the laptop is turned on.

The battery and/or the laptop has an internal circuit that essentially
stops the charging when the battery is fully charged. However, there
may continue to be a small "trickle charge" in some cases, and it is
either the trickle charge or simply heat from other parts of the laptop
that can slowly damage the battery.

But the manufacturers, as far as I know, never tell you any of this,
they tell you to keep the battery in the laptop constantly.

The rule I'd recommend: If the laptop is going to be plugged in for
days at a time (or longer, weeks, months), remove the battery. But if
you are traveling and will truly be using the battery, just leave it in
until the traveling is done.

Also, consider getting a small, low-power UPS (say 300 to 400 VA) if you
are using the laptop permanently plugged in with the battery removed.
This should cost $30 or less (and sometimes these are on sale "free
after rebate")


sp_nrc********.com wrote:

> Hi,
>
> My mom recently got a computer and I have been helping her with it.
>
> I read in the instruction manual that you should never charge the
> battery for longer than the required time because if you keep charging
> the battery when it is full the battery will be damaged.
>
> When the computer is turned off and the power cord is connected the
> computer takes four hours to charge.
>
> When the computer is turned on and the power cord is connected the
> battery will take 12 hours to charnge.
>
> My questions is this: When the computer is connected to the power cord
> and the battery is full, won't the battery be damaged from over
> charging? Is there some way to stop the battery from charging when the
> power cord is plugged in? My dad think that we may have to remove the
> battery when we use the power cord to run the computer.
>
> Thanks for any help,
> Andrew
>

Barry Watzman wrote:

> Re: "I read in the instruction manual that you should never charge the
> battery for longer than the required time because if you keep charging
> the battery when it is full the battery will be damaged."
>
> I have never seen that stated in a manual, and it should not be true ...
> but at some level, it is. We know that if you leave a battery in a
> laptop that is continually powered from AC, over time it will be
> damaged. But the damage is very slow and takes a LONG time to occur (6
> months to 2 years). It's not normally a problem in terms of casual use.
> There should be no problem leaving a battery in for days or weeks at a
> time, but if the laptop is always plugged in, then you are better off
> removing the battery, or it will be damaged (very, very slowly, over
> months or years, not days or weeks).
>
> The charging behavior that you are seeing is normal. It should take
> longer (a lot longer) to charge when the laptop is turned on.
>
> The battery and/or the laptop has an internal circuit that essentially
> stops the charging when the battery is fully charged. However, there
> may continue to be a small "trickle charge" in some cases, and it is
> either the trickle charge or simply heat from other parts of the laptop
> that can slowly damage the battery.
>
> But the manufacturers, as far as I know, never tell you any of this,
> they tell you to keep the battery in the laptop constantly.
>
> The rule I'd recommend: If the laptop is going to be plugged in for
> days at a time (or longer, weeks, months), remove the battery. But if
> you are traveling and will truly be using the battery, just leave it in
> until the traveling is done.
>
> Also, consider getting a small, low-power UPS (say 300 to 400 VA) if you
> are using the laptop permanently plugged in with the battery removed.
> This should cost $30 or less (and sometimes these are on sale "free
> after rebate")
>
>
> sp_nrc********.com wrote:
>
> > Hi,
> >
> > My mom recently got a computer and I have been helping her with it.
> >
> > I read in the instruction manual that you should never charge the
> > battery for longer than the required time because if you keep charging
> > the battery when it is full the battery will be damaged.
> >
> > When the computer is turned off and the power cord is connected the
> > computer takes four hours to charge.
> >
> > When the computer is turned on and the power cord is connected the
> > battery will take 12 hours to charnge.
> >
> > My questions is this: When the computer is connected to the power cord
> > and the battery is full, won't the battery be damaged from over
> > charging? Is there some way to stop the battery from charging when the
> > power cord is plugged in? My dad think that we may have to remove the
> > battery when we use the power cord to run the computer.
> >
> > Thanks for any help,
> > Andrew
> >

Some of the IBM Thinkpads do exactly this: they have
(thinkpad-specific, unfortunately!) software that will offer to only
charge the battery to, say, 96% if you tend to use it almost
exclusivley on mains power, to better condition the battery.
suspect this isn't practical via 3rd party software though..
ric