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will an old, unused Li battery be a risk?

Discussion in 'Laptops' started by scrunchy2k, Jul 15, 2005.

  1. scrunchy2k

    Donnalynne Guest

    Well, as some posted, a 5 year computer isn't worth much.
    I know you posted about the battery concern, but I would be more
    concerned about the operating system.
    I bought my Dell Desktop 8100 in 2000 and it only came with Win ME.

    Now Microsoft is no longer supporting the ME OS. I can only use MSN8
    on it because of amount of disk space that MSN9 takes,,,,and the list
    goes on about programs that do not work with my old machine. It still
    works, but I would never buy another ME unit.

    But I still consider myself a newbie and I do not have the skills to
    upgrade to XPHomeSP2.

    Good Luck, and do not pay more than $50.00 for it. LOL
    donnalynne
     
    Donnalynne, Jul 17, 2005
    #21
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  2. scrunchy2k

    peter Guest

    Why not TRY IT??. You may well have to renew the coin cell (bios
    back-up), But then charge the main battery and see how long it keeps
    going. After all you say the vendor is a friend, so he should let you do
    this. If it dies factor the cost & availability of a new battery into
    the deal. Li rechargeables have pretty good protection so I wouldn't
    expect any dramatic failure
     
    peter, Jul 17, 2005
    #22
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  3. Anybody know where these chips can be ordered, ideally in the UK ?


    Cheers, J/.
     
    John Beardmore, Jul 18, 2005
    #23
  4. scrunchy2k

    timeOday Guest

    I too have a T770. Some time ago, the battery went "pop!" which scared
    me a bit, so now I run it sans battery.

    As for mp3's, I have played them and it does work (but uses up much of
    the CPU.) Mp3 encoding, however, would be very painful.

    The T770 screen and keyboard, however, are great.
     
    timeOday, Jul 18, 2005
    #24
  5. scrunchy2k

    budgie Guest

    As a commercial Li_ion charger designer, I have done a fair amount of both cycle
    testing and storage testing. After 2 years at room temperatures, a pack of
    three 18650 cells had lost about 10% charge, and that was from full charge. The
    best charge state for long-term storage - and the state in which new packs are
    far more likely to be delivered - will certainly lose no more than this.

    Also, when cell/pack voltage drops below the recharge threshold this does NOT
    preclude recharging. Rather, the pack exhibits a high impedance to the charger
    and absorbs only a "qualifying" charge (similar to under-temperature behaviour)
    until that threshold is reached, at which time normal charging resumes.

    That threshold is not a "death sentence" as you infer. It is applied for two
    purposes. Firstly, to protect the cells against further discharge and possible
    descent into unstable conditions. Secondly, to ensure that "normal" charge
    levels aren't able to be imposed on cells at that SOC.
     
    budgie, Jul 18, 2005
    #25
  6. It may be that the no-charge thresholds are a little different. This is to
    be expected as electronic circuits cannot be made exactly the same. Of
    course it is also possible that the camera has developed a fault and the low
    volt charge prevention doesn't work. But as you seem to have succeeded in
    charging the battery without it exploding, this would seem unlikely.

    Ian.
     
    Ye Electrik Fanne Clubbe, Jul 18, 2005
    #26
  7. The low voltage cutoff threshold exists for a very different reason. Part
    of the chemical reaction that takes place in a Li-ion type cell causes the
    electrolyte to deposit copper on everything and anything including the
    insulation between the anode and cathode connections. By and large, this
    copper is effectively removed permanently from the reaction. Where such a
    cell to be recharged, the copper presents a discharge path. Should
    sufficient copper have been deposited, the resultant short circuit current
    can cause the cell to explosively destruct. If the cell has not ben in this
    state for too long, the copper is thin enough that it gets blown away (like
    a fuse).

    I have some video of cells charged under such conditions, which would do
    much to disuade anyone from risking it.

    Ian.
     
    Ye Electrik Fanne Clubbe, Jul 18, 2005
    #27
  8. It's actually 3.0 volts per cell (but some early chemistries allowed 2.5
    volts).

    The advice about the non flammble area is good, but that needs to be
    extended to ensure that there is nothing flammable with 2 metres of the
    battery. The flame jet from a ruptured cell can typically be 4 long, and as
    it is fuelled by pressurised electrolyte and internally generated oxygen, it
    is quite impossible to extinguish it.

    As a general rule, if the protection circuit allows you to charge it, you
    should be OK. If it doesn't, then this battery has been around long enough
    that it should be discarded.

    Ian.
     
    Ye Electrik Fanne Clubbe, Jul 18, 2005
    #28
  9. scrunchy2k

    Ian Stirling Guest

    You can't order them, they are fully custom chips (or at least enough
    of them are that you can't generally replace them), plus there is no
    data.
    Some manufacturers even use digital signatures, so that 'counterfiet'
    batteries are impossible.
     
    Ian Stirling, Jul 18, 2005
    #29
  10. Hmmm... We had one manufacturer willing to give us some last year, then
    they sacked their staff, closed the plant, and moved production to
    China. Bummer...


    Cheers, J/.
     
    John Beardmore, Jul 18, 2005
    #30
  11. They cannot be ordered, they are custom programmed microprocessor chips
    with firmware specific to the battery in question.
     
    Barry Watzman, Jul 19, 2005
    #31
  12. This is not quite true. In fact, the entire evaluation kit including
    the ICs and other periferals can be ordered, for example:

    http://focus.ti.com/docs/prod/folders/print/bq20z80.html
    or see also similar folder for bq2084.

    Of cause TI is not going to send out a single chip,
    but distributors might, for some extra price.

    Btw z80 is the impedance track gas-gauge, so it can adapt to
    battery itself. It will get all needed parameters, if proper conditions
    for first discharge are provided (see appnotes on the site).

    Regards,
    Yevgen
     
    Evgenij Barsukov, Jul 19, 2005
    #32
  13. scrunchy2k

    Ian Stirling Guest

    I read the original thread as "can I make new compatible batteries", in
    which case the answer is generally right, no you can't.
     
    Ian Stirling, Jul 19, 2005
    #33
  14. scrunchy2k

    budgie Guest

    Barry, the ones we sourced in proto quantities back in late 2002 weren't
    micro-based. Can possibly dig out the URL if it's still here.
     
    budgie, Jul 20, 2005
    #34
  15. You can get the chip, but it is very unlikely to have the same firmware
     
    Barry Watzman, Jul 21, 2005
    #35
  16. This might apply to some different arthitectures that use
    general purpose microcontrollers, but not to BQ ICs like bq2084 or z80.
    These are specialized ICs for sole purpose of battery management,
    and the chip with same part number will always have same firmware
    (apart for some customizations in the data-flash, or version number).

    Regards,
    Evgenij
     
    Evgenij Barsukov, Jul 21, 2005
    #36
  17. scrunchy2k

    Doug McLaren Guest

    | and to clarify what Barry said, "There are plenty of 10-year old
    | lithium-ion batteries that are still alive and kicking." I have one
    | in an Acer laptop that is 9-odd years old and still delivers over
    | half its intial rated endurance.

    If it's 9 years old, are you sure the battery is really lithium-ion?
    If I recall correctly, most laptops used NiMH or NiCd cells 9 years
    ago.

    As for LiIon cells, from what I've seen, they tend to be mostly dead
    after two years, used or not.
     
    Doug McLaren, Jul 24, 2005
    #37
  18. scrunchy2k

    budgie Guest

    Maybe most did, I can't comment. But this one sure is Li-Ion.
    Our experiences differ dramatically.
     
    budgie, Jul 25, 2005
    #38
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