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A Tale of LiPo Resurrection.

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  • A Tale of LiPo Resurrection.

    We've all been brought up in this hobby that once a LiPo has been drained below a certain voltage (3.0v - 3.5v), we may as well throw it away. I've always found this to be true (more or less). I recently left a battery plugged into a plane (absent minded) for almost a week. When I remembered where it was, I got it and tried to measure the voltage with my LiPo checker. The battery couldn't even power it up. The screen was blank. I bought two of these batteries and the "dead" one was slightly soft but not puffy while the "good" one was like new (firm). As an experiment, I decided to see if this "dead" LiPo could be brought back. I had nothing better to do. I put it on my charger (picture of battery and charger below - disregard what the display says as I'm charging other batteries for tomorrow's flying) and selected NiCAD. It defaulted to 1A charging and NiMH. I fired it up and monitored it for about 20 minutes as I watched the meter show the amps being added. It would not allow me to plug in the balance port, so left it unplugged. I took the battery off to check the volts. One cell read 1.0v while the other two were up to just under 3.0v. I put it back on, trying to bring all the cells to at least 3.7v. When that happened (the low cell was at 3.7, the others were just under 4.0v), I reverted back to LiPo balance charging at 0.5A and plugged in the balance port. Slowly, the 3 cells balanced and when it reached about 3.9v/cell, I charged it the usual way at 0.85A. All 3 cells reached 4.19 - 4.2v/cell. The softness remained the same. I've since used it for a flight in the intended plane and it flew just like it always did and was the same as the other battery of the same brand and size. I'll be very interested to see if this once dead battery will last the same as the other one that I bought at the same time for the same planes. Whodda thunk?
    Had lunch with another flying buddy whose cousin left a battery (1300mah, 3s) in his plane for 3 months. He was about to throw it away but he'll give it to me next time we meet and see if that one can be resurrected. That will be an interesting experiment, too.

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  • #2
    The big question.........where are the IR's at
    Warbird Charlie
    HSD Skyraider FlightLine OV-10 FMS 1400: P-40B, P-51, F4U, F6F, T-28, P-40E, Pitts, 1700 F4U & F7F, FOX glider Freewing A-6, T-33, P-51 Dynam ME-262, Waco TF Giant P-47; ESM F7F-3 LX PBJ-1 EFL CZ T-28, C-150, 1500 P-51 & FW-190

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    • #3
      Since you asked, I put both of them on the charger for a couple of minutes just to see. These are 3 photos I took over a 1 minute period while balance charging. The left shows the "good" battery. The right shows the "resurrected" battery. You can also see the cell voltages as well. Not sure what it all means but both seem similar to me.

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      • #4
        Intriguing...................
        Warbird Charlie
        HSD Skyraider FlightLine OV-10 FMS 1400: P-40B, P-51, F4U, F6F, T-28, P-40E, Pitts, 1700 F4U & F7F, FOX glider Freewing A-6, T-33, P-51 Dynam ME-262, Waco TF Giant P-47; ESM F7F-3 LX PBJ-1 EFL CZ T-28, C-150, 1500 P-51 & FW-190

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        • #5
          Xviper keep us posted on the resurrected battery. I have a 2200 mah battery that is at 0 volts. I'm thinking of going through the charging process you did there. I'll charge it in my bbq. In case the thing decides to explode. With the bbq off of course.

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          • #6
            Originally posted by Skyboom View Post
            Xviper keep us posted on the resurrected battery. I have a 2200 mah battery that is at 0 volts. I'm thinking of going through the charging process you did there. I'll charge it in my bbq. In case the thing decides to explode. With the bbq off of course.
            I too, was worried about the battery blowing up so I kept monitoring it for heat, puffiness or any other abnormal behavior. It never got even warm during the revival nor did it get any softer or did it puff up. Maybe this was a fluke. I will hopefully get the other dead battery that was in the plane for 3 months in a couple of weeks and give that one the same treatment.

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            • #7
              UPDATE: The battery that was resurrected is still working well in the plane for which it was purchased for. However, it takes a very long time for it to balance on the charger. In fact, it times out but it's still usable in the Mini-Convergence and performs comparable to the "undamaged" one. Nevertheless, the fact that it is so hard to balance, I have a feeling that it won't last too many more cycles.

              Next experiment: I received that other "dead" battery and went through the same procedure. This one is very old (several years). It was totally "dead" and I charged it in NiCad setting at 1A. It's a 1200mah, 3s, 15C. It took a long time to get it to the point where it was accepted on the balance charge setting. It had to be at least 11V total. From there, it went on balance charge for LiPo but that's where it didn't go much further. 1 cell peaked out at over 4.4v, another at 4.2v and the last cell only managed to get up to about 3.0v. I deemed this one as a "failure" and I destroyed the battery by draining it with DC light bulbs.

              In conclusion, this method won't always bring back a dead LiPo but if it's a new battery that you accidentally killed, it might be worth a try.

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