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Thinkpad plug in all day ? Question about batter life

Discussion in 'Laptops' started by buywheels, Dec 2, 2005.

  1. buywheels

    buywheels Guest


    I just purchased a ThinkPad T43. My question is, since I use it as a
    desktop replacement, is it better to leave it plug in all day, or start
    it unplug in the morning , use up the power during the am and then plug
    it in after lunch ?

    What is better for the battery ?

    buywheels, Dec 2, 2005
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  2. Leave it plugged in when you want to - I use an old broken-down battery
    when I do that, as it tends to kill the battery off one way or another
    to leave it in when on a/c. But I like to have a battery in there as a
    portable UPS. My old battery is probably good for half an hour to an
    hour's charge (result of two and a half years's use from new running
    on a/c pretty nearly all the time).
    It's no good to deliberately charge and discharge the battery. Those
    things have a limited number of complete cycles programmed into them.
    300? 600? Anyone know?
    Keeping it 1/3 charged on a shelf at a few degrees C.

    Nothing is "good" for a battery. Many things are bad, however!

    Peter T. Breuer, Dec 2, 2005
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  3. It's best to remove the battery entirely, and if you feel that you need
    it, get a low-cost UPS (APC 350VA UPS' are often on sale for $30 or less).
    Barry Watzman, Dec 2, 2005
  4. buywheels

    Paul Rubin Guest

    The best thing for the battery if you're using the machine on AC power
    all the time is just remove it and stick it in the desk drawer.
    Paul Rubin, Dec 2, 2005
  5. buywheels

    Ian S Guest

    All batteries pretty much begin to deteriorate as soon as they are
    manufactured. My T22 has a charger circuit designed such that the battery
    won't overcharge even if the laptop is left connected to AC all day. Indeed,
    if you charge the battery fully and let it discharge a few % say to 97% then
    plug it in, the charging circuit will not charge it back to 100%. You have
    to let the battery discharge more in order for the charging circuit to begin
    a recharge.

    The battery does degrade the more you discharge and charge the battery -
    i.e. there are a finite number charging cycles so I wouldn't advise the
    second option you suggest. I'm also not convinced that you'll see a really
    significant increase in battery life by simply taking it out and storing it
    as opposed to keeping it in place while running on AC all the time. And as
    another poster states, if you remove the battery, you should then use a UPS
    to prevent loss of data in the event of a power failure. My experience? My 7
    year old 560x battery no longer holds much of a charge. My 4 y.o. T22
    battery still maintains some capacity - more than 1 hr - and I have never
    stored the batteries outside the laptops.
    Ian S, Dec 2, 2005
  6. buywheels

    Paul Rubin Guest

    The advantage of leaving the battery installed is that the most common
    power failure with a laptop is you knock loose the AC plug. A UPS
    doesn't help with that.
    My X40 battery (1 y.o.) has seen maybe a couple dozen charge cycles
    tops. It now holds about 70% charge according to the ACPI
    measurement. Lithium ion batteries, start deteriorating as soon as
    they are made. That happens whether you use them or not.
    Paul Rubin, Dec 2, 2005
  7. While that is technically true, Lithium batteries that are well cared
    for can last a decade.
    There are some laptops that don't seem to damage the battery by leaving
    it in the laptop, but that is definitely the exception rather than the
    rule. But the damage is not necessarily due to overcharging, in any
    case (although in some cases, it is). Heat is a culprit also, and is a
    major factor in some models, where heat from the cpu or hard drive heats
    up the battery. And overcharging clearly can be a problem also on a
    model-by-model basis.
    Lithium ion batteries are good for "a few hundred" cycles. It's not
    clear how a partial cycle "counts" in this equation. Deep discharges
    definitely shorten the life much more than partial discharges.

    Well, that point is ***VERY*** clear, the difference is at least
    potentially huge. Most laptops (maybe not yours, but most) will destroy
    a battery left in while the laptop is continually on AC within 6 to 24
    months, and well cared for lithium batteries (this actually includes
    SOME use) can last 10 years.
    You ae making MY case. I agree that IBM has one of the best charging
    systems, you are right, they won't re-start charging what was a fully
    charged battery until it's charge drops. Most laptops charge
    CONTINUOUSLY when plugged in no matter what the state of the battery.
    Yet even your IBM laptops have significantly damaged what was a good
    battery in less than 4 years. Most laptops do far more destruction far
    faster (trust me, they do).
    Barry Watzman, Dec 3, 2005
  8. Although the statement is literally and factually true, you way
    over-state how quickly they deteriorate if properly cared for (mostly
    stored, but SOME use and charge every few months). I have piles of
    Toshiba 2487 series lithium batteries with 1995 and 1996 date codes that
    will still run a Toshiba laptop (in fact one that draws a LOT more power
    then the ones that they were made for) for 2 hours. These came, at
    random, from machines that I buy (often on E-Bay or from corporations)
    for repair / recycling / parts. Sometimes they have been sitting unused
    for years.
    Barry Watzman, Dec 3, 2005
  9. buywheels

    Ian S Guest

    maybe so but few people will have much use for the ten year old laptop to
    which it's attached.
    What do you mean "last"? I don't believe any battery, lithium or otherwise,
    would maintain anywhere near its original capacity over that period of time.
    Well, I bought the laptop refurbished over a year and a half after it was
    built and I have no history on the battery before that time. Furthermore, I
    have never discharged the battery so I really don't know just how long it
    will last. The O.P. was asking specifically about a ThinkPad so my response
    was in answer to ThinkPads specifically. Now, I find all this wailing and
    gnashing of teeth over laptop batteries almost laughable. I can buy a
    replacement battery (brand new aftermarket) for under $90. That works out to
    about $0.06 per day based on the four years of service out of my T22. That's
    a fraction of the change I throw into my spare change jar every day! As for
    a battery lasting ten years, consider just what kind of laptop you'd have
    bought ten years ago. You'd be lucky if it was even a Pentium! I guess my
    point is don't sweat over a ThinkPad's battery life.

    Most laptops do far more destruction far
    Ian S, Dec 3, 2005
  10. buywheels

    Paul Rubin Guest

    It's still a PITA. $90 is a good fraction of what your T22 is worth
    these days. So if you have this otherwise perfectly good T22 and it's
    going to cost you $90 to keep it in service, you have a dilemma.

    You did good, having that battery stay useful for 4 years. My X40
    battery now holds about 70% of its original capacity though it's only
    about 1 year old and has had maybe a dozen recharges. The X40 is not
    even that heavily used (it's a secondary machine).
    Paul Rubin, Dec 3, 2005
  11. Hi,

    How has your experience been with those batteries? Any particular
    brand/vendor you can recommend? My T23 battery lasts for about an
    hour at most these days, so I have been thinking about replacing

    Esmail Bonakdarian, Dec 3, 2005
  12. buywheels

    Ian S Guest

    What's the altenative - spend 15X that on a new TP? When my T22 is doing all
    I want it to? A $90 battery starts to look like a bargain. Especially when
    you consider the hassle of moving your apps to a new laptop. Yes, I know you
    can clone your hard drive but after a number of years, there's sure to be a
    buildup of trash that it seems ill-advised to transfer to the new laptop.
    Better to start from scratch. In my case, I doubt I'd want to transfer the
    the old WIN2K operating system either. It's somewhat analogous to putting a
    new transmission in a ten year old vehicle except that in the case of the
    laptop, it's liable to be LESS risky because of the reliability of the rest
    of the components apart from maybe the hard drive. Speaking of which, a lot
    of people don't seem to mind upgrading to a larger faster hard drive for
    their one or two y.o. laptop even though that's more costly and way more
    hassle than replacing a battery.
    That's a bit discouraging but I wonder how deep those discharges were. In
    any event, battery technology is always improving so we're apt to see better
    battery life in future laptops.
    Ian S, Dec 4, 2005
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