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"Sulphated" NiCads

Discussion in 'Electronic Repair' started by N Cook, Dec 16, 2005.

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  1. N Cook

    N Cook Guest

    When that white crystalline material forms on th ends of the cells and the
    impedance goes high and they become useless. What is that substance and how
    harmfull is it ?
    Is it the same process, in effect, that renders lead-acid cells uselss - a
    build up of an insoluble salt so the ions cannot pass to/from the lead to
    the electrolyte?
  2. default

    default Guest

    The cells tend to leak if left discharged for a long period. How
    harmful would depend on what you plan to do with it. Its not good to
    eat and may kill you, pollute the environment, etc.. Cadmium is very
    poisonous, nickel is poisonous, they may contain small/trace amounts
    of mercury as well.

    I don't know the chemistry of nicads, but do know they are radically
    different from lead acid, so a different failure mechanism might be at

    Most of the cells I have experience with (back in the day) short
    internally, If left in that condition, over time, they leak, or just
    corrode from the inside out. Cells that have an internal short can
    often be rejuvenated by burning the short out with a discharge of
    heavy current through it. We used to build power supplies that would
    charge a cap to dump energy into the short for that purpose.

    Throw them out and get new rechargeable's. Once they leak, they've
    had it.
  3. Guest

    I hope you are able to reply to this message. In the event you
    touched that leaking chemical, you will die within 12 hours or less.
    Its absorbed thru the skin and eats a hole thru your brain, eventually
    devouring your entire brain. If you are still able to read this
    message, you may no longer be able to comprehend it because your brain
    is partially eaten away. I'd tell you to contact a doctor, but it's
    too late. There is no way to stop this brain decay. However, there
    is a possible light at the end of the tunnel. One out of 100 people
    do survive. They have little if any remaining brain matter, but there
    is enough left to remind them to breathe and keep their heart beating,
    Most of them end up in Texas and join the rodeo. However one of them
    went to Texas and later moved to Washington DC to become the president
    of the United States. His name is George W. Bush. Doctors have
    evaluated this man and found little working brain matter. They all
    said it's a miracle he is alive.

    Good Luck
    You need it !!!
  4. BAD IDEA! The cadmium in them is very toxic. That's why you should be
    careful about those crystals from a leaky one, and also why you should
    never "throw them away", but dispose of them properly as toxic waste.

    NiMH use a different chemistry, and are nowhere near so bad.

  5. N Cook

    N Cook Guest

    in message

    Googling around , the electrolyte in NiCads would seem to be potasium
    chloride and the white crystalline buidup is probably just potassium
  6. BE

    BE Guest

    Please, never THROW OUT any batteries. Take them to Radio Shack or your city
    haz-mat center so they can be recycled. It scares me to consider all the
    batteries that get thrown in the trash, which then go on to leach their
    toxic substances into groundwater.

  7. Guest

    What about the plain carbon acid flashlight batteries? Are they bad
    to dispose? I dont think recyclers even take them, or the common
    alkaline batteries?
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