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battery life - used when plugged in?

Discussion in 'IBM Thinkpad' started by Mott, Feb 23, 2007.

  1. Mott

    Mott Guest

    Hi my T60 has a 9-cell battery which is only on cycle 13 and I really
    want it to last. I use it as my main machine plugged in to the mains
    power at a desk most of the time and on battery power only 10 hours or
    so a week.

    So, does the battery get used even when plugged in? i.e. when plugged
    in it is the case that:
    the battery is charging -> the thinkpad uses power off the battery ->
    the battery gets constantly charged
    the thinkpad uses direct main power ignoring the battery -> the
    battery only is charged as per your power settings?

    If the latter is true, how come I can pull out the power lead and the
    laptop carries on running (unless there's a backup capacitor that
    helps with a seamless switchover to battery power).

    I'm so nervous that it's using the battery when plugged in that I
    remove the battery every time I plug it in to save it's overall
    lifetime! I do tis even though my power settings are set to "adjust
    for best battery life"

    am I being ridiculous?

    Mott, Feb 23, 2007
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  2. Mott

    none Guest

    Hi Mott,

    I don't know how the thinkpad uses the battery when it's fully charged and on ac
    power. But don't forget that the battery gets hotter when it's inside the
    laptop, and heat doesn't expand battery lifetime at all ;-)


    IBM Thinkpad T43p - Gentoo Linux
    kratchkov [at] inbox [dot] lv
    none, Feb 23, 2007
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  3. Mott

    Ed Guest

    I can not comment directly on the Thinkpads, but in almost every
    case of electronic equipment that runs on battery that I have been
    exposed to, the battery charge remains stable while the charger is on
    and the equipment is running. If the battery is fully charged, then any
    excess charge capability from the charger circuit is going on to run the
    equipment. Yes, the battery is still there in the circuit so if the
    charge circuit is turned off, (unplugged), the battery takes up the
    slack; There is no "switching" as you appear to wonder about in this

    But as another poster mentioned, heat is not your battery's friend,
    and I must suppose that there would be a measurable shortening of its
    life if left in the warm/hot laptop while the laptop is running off the
    power coming from the charge circuitry. On the other hand, constantly
    removing and re-inserting the battery is probably far more likely to
    cause damage.

    Just my opinion.

    Ed, Feb 23, 2007
  4. I use T43 for the last 1.5 years and am battery life conscious too.
    In Power management -> battery information -> battery maintenance tab I
    have set to start to charge below 77% as opposite to default, I believe
    96%. The internal battery circuitry will not charge that often what is
    translated to less charging cycles. Still as posted here heat is enemy,
    what is best balance?, good question. Well you cannot have everything
    so for me, this I believe minimal lost of charge is worth trade off.
    The Last Westman, Feb 23, 2007
  5. Mott

    Larry Guest

    Every Laptop battery I've ever owned has gone bad, plugged in or not.

    My T20 and T21 were almost never on battery, and both died within 2 years.

    Larry, Feb 24, 2007
  6. Mott

    Jan Andersen Guest

    My T30 battery still holds 78% of its Design Capacity after 4 years and
    4 month (almost always plugged in).
    My R51 battery have degraded to 75 % already after 2½ years treated the
    same way.

    Jan Andersen, Feb 24, 2007
  7. Mott

    Ed Guest

    How did you measure the above capacities? I think my 14mo old R50e is
    already showing signs of battery deterioration. It is used very little....
    maybe once a week... sometimes daily for hours, but mostly not.

    Ed, Feb 24, 2007
  8. Mott

    Jan Andersen Guest

    Battery Information>Battery Helth: Design Capacity 47.52 Wh and Full
    Charge Capacity 36.94 Wh for the T30

    Jan Andersen, Feb 24, 2007
  9. Mott

    Ed Guest

    Oh Drat! I just replaced my factory Thinkpad HD with a new larger one
    and installed a fresh, stock, Windows XP on it. My nice Thinkpad battery
    minder software is on the old HD, so guess I won't be able to use the above
    method. Thanks, anyway.

    Ed, Feb 24, 2007
  10. Mott

    Jan Andersen Guest

    You can always download Drivers and Utilities from IBM/LENOVO's website
    (Battery MaxiMiser).

    Jan Andersen, Feb 24, 2007
  11. Mott

    Ed Guest

    . . . err,, right! I often forget that there is such an excellent
    support site for these Thinkpads.

    Thanks, Jan.

    Ed, Feb 25, 2007
  12. Lenovo RECOMMENDS removing the battery from the system when left
    plugged in for long periods of time (at least on the old 600 and 770
    series) for heat reasons.
    clare at snyder.on.ca, Feb 26, 2007
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