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battery charge behavior - Mac Portable

I have a 1.5 year old 15" Powerbook. When new, the battery would top off its charge when the level dropped to below 95%. Now, the level needs to drop below about 83% before it re-charges. Another difference is that the light on the charger used to glow green when it was in that state (below 100%, but not charging) - now, it glows amber. I'm not complaining, just wondering if someone has an explanation. I rarely use it on battery. I'll go for days at a time just carting it asleep between work and home and plugging it in ...

  1. #1

    Default battery charge behavior

    I have a 1.5 year old 15" Powerbook. When new, the battery would top off
    its charge when the level dropped to below 95%. Now, the level needs to
    drop below about 83% before it re-charges. Another difference is that the
    light on the charger used to glow green when it was in that state (below
    100%, but not charging) - now, it glows amber. I'm not complaining, just
    wondering if someone has an explanation.

    I rarely use it on battery. I'll go for days at a time just carting it
    asleep between work and home and plugging it in as soon as I arrive. So
    it's spending a lot of time in the amber state as it slowly falls from
    100% to 83% during the commute intervals.

    Thanks,
    Susan
    Susan Hall Guest

  2. #2

    Default Re: battery charge behavior

    In article <280820032117043216%thomasareeddont.spam.me>,
    Thomas Reed <thomasareeddont.spam.me> wrote:
    >In article <susanhal-2808031820000001bigears.psychology.dal.ca>, Susan
    >Hall <susanhalis.dal.ca> wrote:
    >
    >> I rarely use it on battery. I'll go for days at a time just carting it
    >> asleep between work and home and plugging it in as soon as I arrive. So
    >> it's spending a lot of time in the amber state as it slowly falls from
    >> 100% to 83% during the commute intervals.
    >
    >You probably need to recondition your battery.
    Possibly not: a 1.5 year old 15" PowerBook probably has a
    Lithium Ion battery (you can check it, Susan, it'll be on the
    label if you take the battery out of the PowerBook). These
    do not have the 'memory' characteristics associated with the
    Nickel-Cadmium system used in earlier rechargable batteries.

    However, if you keep them at full charge for a long time they
    do gradually lose their capacity. So what I'd recommend to
    Susan is that she try letting the battery discharge once a
    week or so: take it home or to work as normal but don't plug
    it in until it gives the low-power warning. If they battery
    can last a whole office-time or home-time without recharging,
    so much the better.

    Note that LI batteries aren't really expected to last longer
    than three or four years anyway: they have both a limit on
    lifetime and a limit on the number of charge/discharge
    cycles they can go through (about 3,000). Your pattern of
    use involves two charge/discharge cycles a day which is what's
    causing your problem.


    Simon Slavin Guest

  3. #3

    Default Re: battery charge behavior

    In article <BB782BEE9668175710.0.1.2>, Simon Slavin
    <slavinshearsay.demon.co.uklocalhost> wrote:
    > >You probably need to recondition your battery.
    >
    > Possibly not: a 1.5 year old 15" PowerBook probably has a
    > Lithium Ion battery [...]. These
    > do not have the 'memory' characteristics associated with the
    > Nickel-Cadmium system used in earlier rechargable batteries.
    Well, I know I read somewhere -- I think in the docs that came with it
    -- that the battery in my brand new PowerBook G4 should be completely
    drained (to the point that the machine puts itself to sleep) and then
    recharged if you notice that the battery life has shortened.

    --
    -Thomas

    <http://www.bitjuggler.com/>
    Thomas Reed Guest

  4. #4

    Default Re: battery charge behavior

    Thomas Reed <thomasareeddont.spam.me> wrote:

    Susan Hall <susanhalis.dal.ca> wrote:
    >
    > > I rarely use it on battery. I'll go for days at a time just carting it
    > > asleep between work and home and plugging it in as soon as I arrive. So
    > > it's spending a lot of time in the amber state as it slowly falls from
    > > 100% to 83% during the commute intervals.
    >
    > You probably need to recondition your battery. Use the machine
    > unplugged until the battery is totally drained. (That is, until the
    > machine goes to sleep because the battery is too low to continue
    > working.) At that point, plug the battery back in. I think that doing
    > this once ought to do the job, but it couldn't hurt to do it two or
    > three times, and then repeat it every 3-6 months.
    I keep reading that Lithium Ion batteries don't need reconditioning (mine
    is one), and yet the other day I let it go on battery down to 40%, and now
    at least the light is back to glowing green instead of amber at 98% on the
    way down again. I'll soon see at what % the charger kicks in.

    I did run the battery down to sleep when I got the machine as described in
    the booklet (I almost said manual, heh), and down almost to sleep a couple
    of other times since I've had it.

    Susan
    Susan Hall Guest

  5. #5

    Default Re: battery charge behavior

    In article <310820031958235385%thomasareeddont.spam.me>,
    Thomas Reed <thomasareeddont.spam.me> wrote:
    ><slavinshearsay.demon.co.uklocalhost> wrote:
    >
    >> >You probably need to recondition your battery.
    >>
    >> Possibly not: a 1.5 year old 15" PowerBook probably has a
    >> Lithium Ion battery [...]. These
    >> do not have the 'memory' characteristics associated with the
    >> Nickel-Cadmium system used in earlier rechargable batteries.
    >
    >Well, I know I read somewhere -- I think in the docs that came with it
    >-- that the battery in my brand new PowerBook G4 should be completely
    >drained (to the point that the machine puts itself to sleep) and then
    >recharged if you notice that the battery life has shortened.
    I would be interested in the source if you ever find it again.
    Totally draining a Lithium Ion battery is not good for it.


    Simon Slavin Guest

  6. #6

    Default Re: battery charge behavior

    In article <susanhal-0309031228490001bigears.psychology.dal.ca>,
    [email]susanhalis.dal.ca[/email] (Susan Hall) wrote:
    > Thomas Reed <thomasareeddont.spam.me> wrote:
    >
    > Susan Hall <susanhalis.dal.ca> wrote:
    > >
    > > > I rarely use it on battery. I'll go for days at a time just carting it
    > > > asleep between work and home and plugging it in as soon as I arrive. So
    > > > it's spending a lot of time in the amber state as it slowly falls from
    > > > 100% to 83% during the commute intervals.
    > >
    > > You probably need to recondition your battery. Use the machine
    > > unplugged until the battery is totally drained. (That is, until the
    > > machine goes to sleep because the battery is too low to continue
    > > working.) At that point, plug the battery back in. I think that doing
    > > this once ought to do the job, but it couldn't hurt to do it two or
    > > three times, and then repeat it every 3-6 months.
    >
    > I keep reading that Lithium Ion batteries don't need reconditioning (mine
    > is one), and yet the other day I let it go on battery down to 40%, and now
    > at least the light is back to glowing green instead of amber at 98% on the
    > way down again. I'll soon see at what % the charger kicks in.
    >
    [snip]

    Note that your battery's actual state of charge is controlled by the
    on-battery charge controller, and you won't affect it's limits on
    state-of-charge by draining and charging the battery. All you do is
    re-set your display. This would be rather like re-calibrating your
    automobile fuel guage by running the thing out of gas, then filling it
    up completely. You haven't changed the size of the tank, only the
    accuracy of the guage by knowing exactly where full and empty are).

    Li-chemistry batteries don't get "memory effect." Under the conditions
    where a Ni-chemistry battery would have this happen, a Li-chem. battery
    would likely catch fire. The on-battery charge controller is there to
    prevent this.
    John Johnson Guest

  7. #7

    Default Re: battery charge behavior

    In article <3f5682a3news-1.oit.umass.edu>,
    "Joe Heimann" <heimannecs.umass.edu> wrote:
    > [url]http://docs.info.apple.com/article.html?artnum=86284[/url]
    >
    >Apple only calls for this to be done every few months, not on a regular
    >basis such as once a month. Hope this helps.
    Many thanks.


    Simon Slavin Guest

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