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Why do Lipo Batteries "Puff up"

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  • Why do Lipo Batteries "Puff up"

    I have never flown batteries to below nominal or charged too fast or too long. Why are they puffed up? Are they useable?
    I currently have 3 puffed packs that all readings for total voltage and each cell reads appropriately too. Again, are they usable?

  • #2
    I'm no expert but in my experience too fast a discharge will cause puff packs. I think this is due to too low an actual C rating versus whats printed on the battery.

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    • #3
      one of the main causes of puffing is heat.

      The higher the charge level, the lower the temp needed to cause puffing.

      High current demand with relatively low charge level will heat the packs rapidly.


      Quality of the packs will affect when they puff but a full 20C Zippy will puff at appx 140F
      FF gliders and rubber power since 1966, CL 1970-1990, RC since 1975.

      current planes from 1/2 oz to 22 lbs

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      • #4
        Heat is the killer of all things electric. When a battery is over taxed it will produce a massive amount of heat and that will cause the dreaded puff up. So your best bet is buy the highest C rating you can, run them to about 3.8-3.7v per cell and leave them until you are ready to fly the next time with the pack. Don't recharge them then let them sit. If you do charge them then use them a few days later you will get puffing as well. Make sure you have them at a storage safe level between 3.9-3.7v per cell when you don't plan to use them for more than 3 days unused. As for the puffed batteries, you can still use them for the time being, but you will start seeing loss of performance faster the more you use them. In the end though they will become unusable alot quicker than a battery treated correctly with the steps pointed out above. Also be aware that a lower than adequate C rating pack on a power system designed for more than what the pack can push out will not only hurt your pack but also heat up your esc and motor. So, keep it in mind that also if these are stock batteries that came with a plane, or their "replacement packs", they don't always (or in my experience) ever put a lipo capable of the planes needs. It's only adequate to just fly the plane. That's why those stock packs come out of the plane hot as hell, and after only a few flights the puff comes on.
        I hope that helps along with what fhhuber has said. Good luck and happy flying!

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        • #5
          Originally posted by Corsair 167 View Post
          I have never flown batteries to below nominal or charged too fast or too long. Why are they puffed up? Are they useable?
          I currently have 3 puffed packs that all readings for total voltage and each cell reads appropriately too. Again, are they usable?
          I'm curious about this statement ......................... Today's LiPo chargers turn off when a battery has reached full charge (~4.2v/cell). How does one charge for "too long"?

          As an interesting anecdote ...................... A few days ago, I pick up a couple of batteries that a friend forgot at the field just so they don't go missing. Both are the same mah and cell count. One was a low C Turnigy "blue" and the other was a high C Turnigy Heavy Duty. My buddy flies all his batteries the same way and charges them the same way. (Basically, he's not kind to his batteries.) One was puffed and one wasn't. Guess which one was puffed?

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          • #6
            Guessing the blue one, and probably will just take alittle longer for the HD to start to puff up. But I have a feeling of he keeps the treatment up, itll either puff or loose a cell before too much longer. I have buddies with puffed Graphenes. Yup multiple people. So for that price they want for them I wont buy.

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            • #7
              The High C are less tolerant of abuse and known to puff under conditions that won't puff the old 20C to 25C blue wrapped packs.
              FF gliders and rubber power since 1966, CL 1970-1990, RC since 1975.

              current planes from 1/2 oz to 22 lbs

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              • #8
                Interesting, I've always found it the other way around. But maybe because of what I listed above in how I been running my packs after researching and understanding how to get the best longevity out of my packs.

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                • #9
                  Originally posted by rifleman_btx View Post
                  Guessing the blue one, and probably will just take alittle longer for the HD to start to puff up. But I have a feeling of he keeps the treatment up, itll either puff or loose a cell before too much longer. I have buddies with puffed Graphenes. Yup multiple people. So for that price they want for them I wont buy.
                  You guessed right. The HD is holding up much better than the blue but it too, is starting to puff. I have quite a few well used Graphenes, some are getting toward 3 years old. I take care of them as best I can. Never drained below 3.7v/cell. Always charged at 1C. None have started to puff and all still perform quite well. I'll only buy Graphenes or HD, Gens Ace or Admirals.

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                  • #10
                    Much agreed, good times

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                    • #11
                      Good infor Rifleman...
                      I gotta watch my storage, as I usually keep them ready to fly. But they seldom sit for more than 3 days, before I run em’. Might be better to leave them at 3.8 until night before I go fly, eh?
                      I had 2 eFlite batteries puff but I worked them kinda hard on a few flights when I first re-entered the skies in January, I pretty much only use them as testers and short flights. Been using Admirals with no signs of puff and only had 1 or 2 “dead stick’ battery mistakes and they were at 3.7 V.

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                      • #12
                        Yeah, 3.8 is the optimal storage voltage, they are normally just as happy at mid 3.7-3.8. But at 3.7 yeah I would add just enough to get it into the sweet spot. My packs normally go a week between uses. And so far all my latest packs I've been flying with since I started correctly caring for them have been doing really well. Solid power, and consistent flight times with no sign of puffing up have kept me happy.

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                        • #13
                          Puffing, or gassing, occurs when the temperature inside the battery gets to a point that it starts to boil the electrolyte causing it to gas. Rifleman is correct in that this will not only degrade the performance of the battery; and if done to the point that a rupture occurs you will have a thermal runaway... And a dreaded LiPo fire.

                          I would add that a good battery charger that has a balance charge is also a worthwhile investment. When a charger goes through a charge sequence, it charges the battery as a whole. A balance charge will look at the individual cells during the charge, and provide a load on the cell(s) as needed to ensure all are charging at an equal rate & amount.

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                          • #14
                            Thanks for all the information.......................

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                            • #15
                              maybe is you charge it or discharge it really at a high C-rating, or post in some wrong place. you could find more lipo care guide at here: https://www.genstattu.com/bw

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