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O/T How to charge dead batteries.

Discussion in 'Uncategorized Threads' started by Shooting Jack, Oct 14, 2008.

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  1. Shooting Jack

    Shooting Jack Active Member

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    First let me say, I assume no responsibility if you have any problem getting this to work. I used these directions exactly as directed and it worked fine for me. Jackie B.



    Nickel Cadium batteries have a tendency to grow internal “whiskers” called “crystal dendrite” growth. Those whiskers eventually discharge the battery completely. This often happens due to overcharging. Be sure to remove your batteries and not leave them in the charger. This growth can be blasted away with a quick jolt from car batteries, DC power supplies, or even a welder will do the trick. The process revives the cells or batteries by the injection of a short-duration high-magnitude current pulse through them.

    The procedure is basically to quickly arc it across two 12 volt car batteries. One caution: do all this rapidly. Follow the guidelines below depending on your particular battery voltage. Safety first, folks. Use goggles and gloves.

    For 9.6 to 24 volt batteries, you’ll need two car batteries to generate enough
    of a jolt. How long you hold the surge depends on the voltage of the rechargeable. See the chart below for surge times.

    FIRST: Wire your two car batteries in series (see figure below).

    This can be done without removing the batteries from the cars if preferred (be sure to remove positive leads to the car). You can use common jumper cables if desired. Series wiring is where two or more batteries are hooked together in series (i.e. positive terminal of the first battery is hooked to the negative terminal of the second battery). The resulting voltage is the sum of the individual battery voltages - if two 12V batteries are hooked together, the resulting voltage will be 24V. Wearing protective glasses is recommended.


    Next hold the stripped ends of your wires to the rechargeable in the following pattern. It is best if the negative side can be fixed to the rechargeable using an alligator clip or in a comparable way. Tap the positive lead to the positive side of the rechargeable for about 10 seconds at a rate of 2 or 3 times per second. Follow the chart below for approximate surge (tapping) time so as not to burn the battery cells.


    SURGE TIMES USING (2) 12 VOLT CAR BATTERIES in series (or a 24 volt equivalent):



    9.6 volt 5 seconds (about 12 taps)


    12 volt 7 seconds (16 taps)


    14.4 volt 9 seconds (20 taps)


    18 volt 10 seconds (25 taps)


    24 volt 12 seconds (30 taps)



    Then charge the battery as usual. If the voltage is not as strong as desired, repeat the process. This can be repeated up to 25 times.




    Below is a link to a video on Youtube of the zap process using a welder for the power source. It’s a bit more dangerous, but interesting.



    http://blog.makezine.com/archive/2006/12/how_to_revive_n_1.html




    Again, I assume no responsibility.
     
  2. Shooting Jack

    Shooting Jack Active Member

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    Just so you will know, I bought these instructions off ebay for $3.00. I had 5 batteries from a kit of saws, drill, light, etc. So I decided to try it. It worked for me. Jackie B.
     
  3. halfmile

    halfmile Well-Known Member

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    Green Bay Wisconsin
    Thisis good, I will try it.

    Re the sulfation: I am not sure but I think one of the problems is that the deposits go to the bottom of the cell and eventually short out the plates.

    In 1957 I had a dead cell in a 6V car battery, they removed one cell and put in a new one.

    They sure don't do that any more.

    HM
     
  4. halfmile

    halfmile Well-Known Member

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    It works. Hallelujah! Now I can bring my old Porter-Cable back online. And the Ryobi POS.

    I used 2 car batteries. Here's a question for you: If the battery gets warm during charging and does not work well, wouldn't that be a sign of the short induced by the little whiskers?

    Next I will fully charge one of these battereies and monitor it's condition for a few days, if the voltage goes down over time I suppose the crystals will still be present to some degree and another zap might help.

    HM
     
  5. LABS4U0

    LABS4U0 TS Member

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    Will this work on NiMH(Nickel-metal hydride) batteries? My dogs shock collar is in need of new batteries. Thx, Darren
     
  6. Little Dog

    Little Dog TS Member

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    What a wuss.
     
  7. halfmile

    halfmile Well-Known Member

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    The creation of dendrites is peculiar to NiCads, as far as I have been able to tell.

    I have been messing with this a little and got good results but a couple wouldn't take.

    Here is what Wiki says:

    Dendritic shorting
    NiCd batteries, when not used regularly, tend to develop dendrites which are thin, conductive crystals which may penetrate the separator membrane between electrodes. This leads to internal short circuits and premature failure, long before the 800–1000 charge/discharge cycle life claimed by most vendors. Sometimes, applying a brief, high-current charging pulse to individual cells can clear these dendrites, but they will typically reform within a few days or even hours. Cells in this state have reached the end of their useful life and should be replaced. Many battery guides, circulating on the Internet and online auctions, promise to restore dead cells using the above principle, but achieve very short-term results at best.

    I am presently monitoring a DeWalt 14.4 that was NFG, given the treatment.

    It reads 16.1 volts now, and ho long it keeps that charge is the question. I think it will go down faster than a new one, but if the treatment made the battery somewhat usable I am happy.

    More to come.

    HM
     
  8. Tron

    Tron Supporting Vendor Supporting Vendor

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    16.1 volts could just be a surface charge. You need to put a load on it and see what the results are.
     
  9. halfmile

    halfmile Well-Known Member

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    Yes, I agree to some extent. Buuuuuut.......I have noticed when these batteries go to pot, they lose their charge without being used. This, I assume is due to dendrite induced shorts.

    I had a Ryobi that was garbage when I bought it (at the Pawn shop) and I gave it the treatment. One battery is fine now, just used it for a lot more than It was capable of previously.

    The DeWalt I am monitoring is going down, but ever so slow compared to before.

    What the heck, nothing to lose here.

    If they don't come back I'll zap them again.

    I really liked the welder trick on the website video. I just used what I had close by - car batteries.

    One of my pet peeves is the high cost of replacement power tool batteries, I feel like we are getting screwed by the MFR's.

    The Wiki page says short term. A few more miles is ok by me, better than nothing.

    HM
     
  10. pendennis

    pendennis Well-Known Member

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    There are some battery sales places which will replace the cells in your battery packs. One of my former coworkers had the cells replaced in both of his Dewalt 12v packs. The cost was well below that of replacment pack costs from Dewalt.

    Best,
    Dennis
     
  11. blizzard

    blizzard Active Member

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    I've been doing this with my MIG for a couple of years.
     
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