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damaged 3S LiPo

Discussion in 'Phantom FC40 Discussion' started by altercactus, May 7, 2015.

  1. altercactus

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    So I have an original phantom 3S LiPo that does not charge and outputs ~8V. From checking the balance plug one of the cells (out of 3) is dead.

    Can this battery be hacked into something useful? Like a 2S for example?
     
  2. IflyinWY

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    Put it somewhere that won't catch fire.

    I'm hoping to see you still posting tomorrow. They do that "Spontaneous Combustion" thing.
    :eek::eek::eek::eek::eek::eek::(:(:(:(:(:(o_O
     
  3. IIVII

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    it's doable , but only if you know what u r doing and have a good soldering skills .. otherwise it's not worth the risk .
     
  4. altercactus

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    Is this not something commonly done? I just hate seeing 2/3 of a good battery go to waste...
     
  5. J.James

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    You could also use it to power some thing that only needs a 8volts. and not even have to do any thing to it.
     
  6. altercactus

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    I like this idea J.James. All I'll have to do is to swap out the balance plug for a 2S

    PS. Just re-checked the balance plug. It goes like this:

    Grey--4V--Grey--4V--Grey--0V--White
     
    #6 altercactus, May 7, 2015
    Last edited: May 7, 2015
  7. IflyinWY

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    So, what did you decide to do with your battery?

    Hope I didn't get too dramatic with my "CATCH FIRE" thing. I have no idea how familiar you are with the LiPo battery.
     
  8. J.James

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    BTW just how dead is the dead cell on this battery. is it zero volts??? Because I was thinking it could also be a wiring issue if its not showing any volts at all.

    I had one that when it arrived there was a tiny break in one of the balance leads right were it went under the shrink wrap and was showing that I had a dead cell and Then i fixed the wire and its worked perfect ever sense
     
  9. altercactus

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    No worries :) Still thinking. I was gonna try to charge it with a hacked together 3S->2S adapter, but J.James is onto something - how can it be exactly 0 volts?

    Good thought! I'm gonna peel off the wrapper and measure on the cell directly.

    What is the significance of the coloring of the wires? Initially I assumed white was ground, but now I'm not so sure
     
  10. altercactus

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    Some news:

    I cracked open the bad LiPo :eek: The white wire is connected to the big red (+) wire - so it is positive, not ground. Checked each cell directly with a multimeter, but as before - 2 cells ok, one compeletely dead. As in 0V, measured directly on its terminals.

    Then, I tried to unsolder some of the connections to do a cell-ectomy but guess what? My soldering iron couldn't melt the gigantic solder blob .. hahaha. I have another soldering iron laying around, so I'll try using two of them at once, hehe.

    PS. Why is there no laughing smiley? Or one of those with the wiggling eyebrows...
     
  11. IflyinWY

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    Ok, interesting news about there actually being ZERO voltage. I'm still having a hard time believing it, but it could be true. I hope you are wearing a face shield and body armor... just kidding - sort of.

    So, inside a battery which should be as light as possible, because that's what we think we're paying for, you find a BLOB of solder which your iron won't even melt. Eeeek. Oh well, maybe shooting with both irons will allow removal of "Gargantuanus Solduras". Let us know how you do.

    A series of pictures, or even a video (especially while you have both irons going) of what you are finding would be very helpful and greatly appreciated.

    Laughing smiley, wiggling eyebrows... well the forum went through a facelift a while back and those features haven't made it too high on the priority list yet.
    Some folks go offsite and bring them in as images.
    I'm one of those folks...


    Ya Got Em Good.gif
     
  12. altercactus

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    got the bad pack removed this weekend. The two soldering guns technique worked (sorry, no pics :( - had my hands full!). The most difficult part is separating the soldered pieces without a second person, but it can be done.

    The interesting part was - the bad pack is completely flat - like a chocolate bar. The two good packs inflated somewhat when I cut the taping that held the 3 cells together. I re-wrapped the new 2s pack tight with capton tape which reduced the bulging. Gonna try using it very, very carefully. What is the physical process behind the bulging? Gas buildup of some kind?

    PS. I was wearing a motorcycle helmet while working on this 8D
     
    IflyinWY likes this.
  13. IflyinWY

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    Goofie as it may sound, I'm thinking the helmet wasn't a bad idea. Thanks for following up. Hopefully someone smarter than me will chime in and let us know about the bulging.
     
  14. mad in nc

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  15. altercactus

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    ok, after reading the referenced thread, here is my understanding:

    1. Puffiness = gas buildup. The gas is methane and ethane.
    2. The danger is not the gas itself, but that the pressure will eventually burst the sealed cell. This hole allows oxygen to enter and a reaction with lithium ensues.

    I saw a video on youtube where a guy did a "gas release". He nicked the wrapping such that the gas is allowed to drain and then resealed the hole with hot glue. I'm guessing that's a pretty dangerous setup.
     
  16. altercactus

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    ... actually after further research - the gas behind the puffing is oxygen. Its source is anode degradation.

    So poking a small hole and resealing it may not be that crazy of an idea, because you wouldn't introduce anything that wasn't already there (drain oxygen, introduce air). The dangerous part would be the hole making itself, since there is a possibility of ignition at that time.
     
  17. IflyinWY

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    Maybe you want to use a welder's helmet... :eek:
     
  18. altercactus

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    hehe, no I'm not that desperate ;) (yet..)