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Can you isolate one cell in a LiPo battery for charging?

Discussion in 'General Discussion' started by PStew22, Jan 12, 2014.

  1. PStew22

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    It may be a stupid question but, can you just isolate the low cell and apply a charge specifically for a closer match the other two (2) good cells?

    I have been using my stock balance/charger which came with my Phantom but noticed deceasing flight times and erratic behaviour during the charging process. It would bring the batteries ( I have three(3) of the same) up to the status of red/green blinking lights and then start blinking red only and alternate the red lights on the cells 1S, 2S AND 3S as if it was trying to balance the cells. I bought a battery checker which indicated the voltage in position 3S was very low in all three(3) batteries were always low. This low voltage in position 3S may be purely coincidenctal but then the thought occurred to me which is why I posted the above question.

    In the meantime I have just purchased a new IMAX B6-AC Charger/Discharger and shall try some of the methods I have seen on You Tube to try to recoup my existing batteries prior to disposing them.

    Sincerely,

    Grounded and looking for comments!
     
  2. OI Photography

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    What deviation are you seeing in the values between the good and suspected bad cell(s)?
     
  3. PStew22

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    Battery #1 3.956 - 3.944 - nothing?
    Battery #2 4.095 - 4.097 - 3.224
    Battery #3 3.900 - 3.893 - 2.840
     
  4. baker745

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    Do any of the packs swell up when you are charging them. It may not be worth the risk to mess with from both a flight standpoint and from a safety/charging standpoint. I just bought a new OEM pack off Amazon for $24.
     
  5. OI Photography

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    Interesting. It's possible your charger isn't really balancing them properly, or your battery meter is faulty on the sensor for the 3rd cell...or that you just happened to get 3 batts in a row with bad 3rd cells. What checker are you using?

    That charger you're getting will help you determine which is the case, and if the batts are truly bad it'll help you save any that can be.
     
  6. PStew22

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    baker745
    My packs are not swollen which is why I am not prepared to do anything until the new charger comes in.

    You are right though, if i get any swelling I am not prepared to risk my bird or accidental fire during charging.

    Still would like to get an answer about focusing on one cell if possible.
     
  7. PStew22

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    I am using the G.T. Power Capacity Controller which I just purchased a few days ago. If I was a betting man I would eliminate the possibility of battery issues due to the coincidence of 3 normally functioning batteries going wonky at roughly the same time. I would also rule out the tester as the reason I purchased it was due to the my battery issues.I am hoping the new charger will assist me in recouping some of my batteries if not all.

    My original question still stands in the subject line.Not sure if my thoughts are correct, but when you look at the battery balance plug you will notice 3 wires and a black ground wire. I assume the three wires specifically relate back to each individual and specific cell and the black ground wire would be common to all to complete the circuit. Therefore is it possible you can isolate the one faulty cell and carefully charge to bring the volts up to match the other cells then balance charge all together?
     
  8. OI Photography

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    I guess it is, theoretically, but I've never seen it done like you're describing, because that's pretty much what a balancing charger (or even just a balancer) should do, bring the cells back to the same values (or close) while charging. A stand-alone balancer can get them balanced before you put them on the charger if you want to do it that way.

    Honestly though, I'm not sure if those batts are going to be worth keeping, but it's worth a try!
     
  9. PStew22

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    Picking up my new balance\charger tonight and shall see what happens. Thanks for your input, much appreciated!
     
  10. PStew22

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    Success!!! I had to discharge my batteries then slow balance charge using .02amps. I got the cells to almost balance on the first go around and decided to discharge and slow balance again. BINGO! Very pleased with the out come.

    I think the problem was with my stock DJI balance/charger.

    Thanks OI Photography.
     
  11. OI Photography

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    No problem...glad you were able to save them! Sometimes a few balancing cycles like that can do the trick, I discovered today I need to try the same with one of my batts that has a suspicious cell.