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preserving unused battery

Discussion in 'Laptops' started by Q, Sep 18, 2003.

  1. Q

    Q Guest

    My new laptop is used almost exclusively in the home while plugged into
    external power. I would like to make the lithium ion battery last as long as
    possible. My thought is to charge the battery, then remove it and store it
    in the refrigerator. If I ever need to use it I'll warm it up and charge it.

    Does anyone else have a scheme to make a battery last a long long time?

    Q
     
    Q, Sep 18, 2003
    #1
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  2. Q

    Ian Stirling Guest

    Discharge to 50%, put in fridge.
    I've put some Li-ion batteries in my freezer, and the one I took out to
    test has suffered no ill effects.
    Condensation is bad.

    --
    http://inquisitor.i.am/ | mailto: | Ian Stirling.
    ---------------------------+-------------------------+--------------------------
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    Ian Stirling, Sep 18, 2003
    #2
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  3. Charge it, remove it, put it back in the laptop for a charge every few
    months. There's no need to refrigerate it, and if you freeze it you may
    actually damage it. It should last for years this way, possibly for a
    decade (I have some 1997 batteries that have been well cared for that
    are still in essentially new condition).
     
    Barry Watzman, Sep 18, 2003
    #3
  4. They suggest to discharge to 3% (basically the default limit at which WinXP
    automatically hibernate) once a month.
    Richard Musil
     
    Richard Musil, Sep 19, 2003
    #4
  5. Q

    Joe Davis Guest

    I'd store it at room temp, not in the refrig.

    You could look at buying a new battery once a year as part of the cost of
    ownership--like buying a new software program, and then you won't be wasting
    a lot of time and effort on battery tricks. I used to take mine out while
    plugged in at home, until I got in a hurry and went to the airport for a
    trip without the battery.
     
    Joe Davis, Sep 19, 2003
    #5
  6. Q

    AJ Guest

    A versatile inventor, researcher and writer, Mr. Isidor Buchmann is
    the president, founder and CEO of Cadex Electronics Inc. writes:

    Li-ion battey basics
    - Avoid full frequent discharges; recharge Li-ion more often. There is
    no memory to worry about.
    - Although memory-free, apply a deliberate full discharge once every
    30 days on batteries with fuel gauge to calibrate the battery. If not
    done, the fuel gauge will become increasingly less accurate.
    - Keep the Li-ion battery cool. Never freeze the battery. Avoid a hot
    car.
    - For prolonged storage, keep the battery at 40% charge level.
    - Avoid purchasing spare Li-ion batteries for later use. Observe
    manufacturing date. Do not buy old stock, even if sold at clearance
    prices.

    Batteries in a Portable World
    http://www.buchmann.ca/default.asp
     
    AJ, Sep 19, 2003
    #6
  7. Hi,

    Do all these battery related discussions mean that
    keeping the battery in the laptop all the time
    is going to reduce the lifetime of the battery considerably?

    Regards
    Rex
     
    Rex Rodrigues, Sep 19, 2003
    #7
  8. Do all these battery related discussions mean that
    Of course. A battery sitting on the shelf will outlast one that you are
    actually using.

    But the battery sitting on the shelf isn't doing you any good!

    I'm with Joe Davis on this. You can certainly make a battery last longer by
    not using it. But then you don't have it ready when you pack up the
    computer, and it's not there to protect you against power failure or
    accidental disconnection of the power cord.

    A more subtle point: On all the ThinkPads I've owned, if the battery is
    removed then the base of the computer is not heavy enough to keep it sitting
    flat when the top is opened. That's fairly annoying, and it may increase the
    likelihood of hard drive damage from the base lifting up with the top and
    then falling back down.

    -Mike
     
    Michael Geary, Sep 19, 2003
    #8
  9. I'd have to quarrel with this part:

    "- Although memory-free, apply a deliberate full discharge once every 30
    days on batteries with fuel gauge to calibrate the battery. If not done,
    the fuel gauge will become increasingly less accurate."

    Those deliberate FULL dicharges will shorten the life of the battery.
    Ok, they may indeed make the guage more accurate. But if the cost of
    making the guage more accurate is actually shortening the life of the
    battery itself, screw the guage.
     
    Barry Watzman, Sep 19, 2003
    #9
  10. Q

    Al Adrian Guest

    Question... Does the IBM T40 use the guage to make decisions as to when to
    shut off the system? If so, it would be one reason to shorten the life of
    the battery a bit in order to keep it accurate. (I think once a month is way
    to often though...)

    My decision (after killing a NiMH in my last Thinkpad) is to leave the
    Lithium battery about half discharged in my laptop bag (so I don't forget
    it) and only pop it into the T40 when I'm moving it, or want to run on
    battery for a little while.. If I decide to do an extended unplugged
    session, I'll have to remember to charge it up first.


    Al...
     
    Al Adrian, Sep 19, 2003
    #10
  11. The paragraph before the one you quarrel with also says:
    " Avoid full frequent discharges; recharge Li-ion more often.
    There is no memory to worry about".

    Clearly, a constant (daily) shallow only discharged pack gauge can
    lead to a very under charged pack and in turn to a potentially
    very unpleasant surprise when a reasonbly accurate capacity is
    needed -- as in the case of a frequent (daily) user of the pack..

    Only if the pack is being little used or stored would such a
    monthly regimen be wasting and also hasten the pack.chemical
    reactants loss since highly charged states (anf high temperature
    -- the real "killer") accelerate their unavoidable loss with each
    charge-discharge. Experience has shown that staying around a 50%
    level gives longest total life capacity for Li-ion.. Pretty well
    in line with " Avoid full frequent discharges; recharge Li-ion
    more often".
     
    H. Dziardziel, Sep 20, 2003
    #11
  12. I don't believe that the "guage" on most laptop batteries is in the
    battery, but I'm not sure of that, and certainly the answer could vary
    by model. I think that the shutdown decision is made by the computer's
    power supply based on voltage only, and not on some arbitrary "guage",
    regardless of whether it be in the battery or the computer.
     
    Barry Watzman, Sep 20, 2003
    #12
  13. I would add that, for the person that's actually using their laptop
    as a mobile computer, a good battery preservation technique I've had
    is to buy a spare battery and actually use it. I find my batteries
    last quite long when I alternate between 2 so they can share the
    use/abuse. I've got 2 batteries I've been using with my Picturebook
    that have followed me through generations (of upgrades). I put the new
    one with the old model I'm selling off and keep the old ones. They
    still work quite well.
    Emanuel
     
    Emanuel Brown, Sep 20, 2003
    #13
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