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  1. #1
    RC Competitor
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    Dec 2009
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    59

    Question for lipo experts?

    I had a 2s 5000mah lipo that puffed one cell. This happened after it had been run in my truck to about 3.8 v per cell. When I put it on the shelf it was fine. I came back 3-4 days later and it was puffed up. I put it in a metal coffee can in a bed of rice and set it outside. After about 2 weeks I went to check on it and it was puffed so tight I thought for sure if I touched it, it would pop. So I decided to try to disassemble it and salvage the one cell that had not puffed. In the process of taking everything apart and had already cut off the battery leads, I laid it on the bench and the exposed battery leads came in contact with the wire cutters. Of course sparks flew and I thought at first that I had been shot. Anyway, I decided that i would liquid tape the bare leads to prevent it from happening again, and that I would wait till after it dried to continue to disassemble it. So I went to put it back in the coffee can and noticed that the puff had deflated quite a bit. It did not vent either. So, I am wondering why would a direct short relieve the pressure from the inside the cell without rupturing it? Also, if it deflates back to the original condition, would it be safe to use it?
    Thanks for any advise or theory that you may have.

    Oh and how should I dispose of the bad cell?
    Caveman
    Hole in Rock, USA

  2. #2
    RC Qualifier
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    Toss that sucker ASAP!!!
    SUMMIT- DeWalt, 4S
    SUMMV- 3S
    MERV- 3S

  3. #3
    RC Champion
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    Don't use it at all. If you want to try to save that other cell, you can try but is it really worth it? Since you shorted the entire battery out, it's not really even worth trying to salvage but that's my opinion. Never a good thing to short out a battery, especially a LiPo.
    I agree with Traxximus '. Throw it out.

  4. #4
    RC Champion
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    I also agree with Traxximus. Dispose of it ASAP.
    I make tap adapters and power harnesses.

  5. #5
    RC Competitor
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    So what is the safest way to dispose of it? Just throw it in the trash for it to go to the land fill or what? Are they recycleable?
    Caveman
    Hole in Rock, USA

  6. #6
    RC Racer
    Join Date
    Jan 2010
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    197

    Exclamation

    My 0.0002c

    Hmmm I'm no expert on lipos (I only have 6x3s 35c each) but if I ever see any of my lipos puff..... It's gone! Period.

    The way I see it, I'd rather buy new ones than lose a finger, a face, an eye ball just to try and save a cell......

    I admire your courage though......
    Rustler VXL & MM
    ERBE
    Summit
    and 6 more...

  7. #7
    RC Champion
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    Jan 2007
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    regina sask, canada
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    i was told you can put it in salt water to discharge it all the way then dispose of it
    if your not breaking anything get more air

  8. #8
    RC poster
    Join Date
    Jun 2009
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    6
    Many hobby stores or tracks will recycle the battery for you. If not your county or city should have a place to recycle used batteries. That is the proper way to dispose of them. The chemicals that make up the battery are toxic and should not be placed in a landfill. If a cell puffs, you can theoretically save the good cells and assemble a new battery. But in practice, the cells will most likely discharge at different rates causing imbalances that could cause additional damage. I agree with the other posters, toss that sucker and save yourself the headaches.

  9. #9
    RC Racer
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    Mar 2009
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    I justed wanted to add too...Toss that sucker!!

  10. #10
    RC Competitor
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    Dec 2009
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    59
    So are you saying that I should throw it away?? Just kidding.

    In an attempt to better understand how these things work. Does anybody know what causes lipo batteries to swell or puff? Or even more intriguing is how could it deflate after being shorted? I went and checked on it this morning and it has no pressure left in it. The foil is stretched out of shape but the pressure is all gone? Anyone care to venture an explanation?
    Caveman
    Hole in Rock, USA

  11. #11
    RC Champion
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    In a SAFE location ..... I discharge the pack by wiring it to an old sealed beam auto headlight and let it run completely down. After checking with a volt meter and making sure the pack is near zero volts ..... I wire nut the positive and negative leads together. This way it stays DEAD!

    Remember lithium reacts when it is exposed to air .... so don't puncture the pack even when fully discharged.

    Put the battery to be recycled in a plastic bag and seal it up.


    Home Depot and Radio Shack recycle batteries.

    Bob
    I make tap adapters and power harnesses.

  12. #12
    RC Qualifier
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    Agreed on the LiPo advice, chuck it, it's definitely no good as a battery anymore when a single cell goes haywire like that.

    If you can use the other cell elsewhere as a single cell, then go for it, otherwise I'd just chuck the whole thing, especially when the HK LiPos are so cheap nowadays.

  13. #13
    Catahoula
    Guest

    Dangerous Battery

    Quote Originally Posted by caveman4466
    So what is the safest way to dispose of it? Just throw it in the trash for it to go to the land fill or what? Are they recycleable?
    Never throw a battery of any type in the trash, please. For all of our sake recycle it. Many cities, fire departments, and businesses recycle batteries. Be careful, we want to see you on the news for winning a race, not for getting hurt.

  14. #14
    RC Champion
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    You shouldn't even try to salvage your other cell. You said you had cut off the battery leads and then when it hit the bench, it shorted. That mean BOTH cells saw the short so you can't even trust the "good" cell to be good anymore.

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