Rescue Over-Discharged Lipo Battery

Over-discharged LiPo batteries sometimes cannot be recognized by LiPo chargers when their cell voltages drop below 3V. In this incidence, I accidentally over-discharged my LiPo battery in my radio transmitter by forgetting to turn it off. In this article I will show you how I fixed it.

If you attempt to rescue an empty-charged battery using instructions in this article, you do so at your own risk. Remember the longer you leave the battery over-discharged, the worse performance it becomes as internal resistance would start going up.

So when this accident happened, the voltage of the over-discharged LiPo battery was measured at a total 1.9V (that’s 0.63V per cell). My charger couldn’t recognize the battery and I thought it might be damaged permanently. But then a friend told me that there could be a fix to my problem.

My understanding is, as soon as we increase the voltage in each cell to a higher level (above 3V per cell) by charging it up using a Ni-MH charger, your Lipo charger might recognize it again. So that was what I did, if you decided to give it a try, do it extremely carefully and do it at your own risk, I won’t be held responsible if you burn your house down. :D


  1. So first of all, you will need a NiMH capable charger. A lot of LiPo chargers can charge NiMH too, like the Turnigy Accucel 6 I had at the time.
  2. I connected the main plug of my battery to the charger, and charge the Lipo with the lowest possible current, e.g. 0.1A. If you have to also set the charging voltage (I didn’t have to in my case), set it to the closest voltage to the nominal voltage of your LiPo pack. (i.e. 7.2v for 2S 7.4v pack, or 12v for 3S 11.1v pack).
  3.  It should only take a few mins to bring the cell voltage back to 3.0V. I recommend to stop the charging as soon as the voltage reach around 3V-3.3V.

After these steps, I then tested it with my LiPo charger, and it finally recognized the recovered battery. I used the Lipo balance charging feature to charge up the Lipo battery to full capacity, and it seemed to work.

Although we can save over-charged batteries this way, over-discharging is not good for the battery life! So remember not to over-discharge your battery whenever possible, and remember to switch off / disconnect your equipment when not in use.

Read about the basics of LiPo battery in this guide.

Edit History

  • Dec 2013 – Article created
  • May 2017 – Article revised

21 thoughts on “Rescue Over-Discharged Lipo Battery

  1. Omkar

    Hi everyone,
    I have 4s/16000 mAH Lipo battery by mistake discharged the battery below nominal voltage(14.8V). Now, the battery is getting charged till 16.8V(max) but it will get discharged automatically(without using) to 13 V.
    I tried above method but didn’t work out. If anyone have solution to this please let me know.

    1. Oscar Post author

      sounds like something is wrong with the charger, are you in the wrong mode? Maybe join our forum ( so we can help you troubleshoot

  2. Daniel Heeps

    Hey everyone, thought I might add/specify something, when charging on ni-mh or ni-cd only plug in the discharge xt60 not the balance plug cos it didn’t work with my smart charger with both plugged in. Only when xt60 was.

  3. Jake

    Not sure if this was the best idea, but I tried this method with a LiFe battery used in my Taranis after the charger detected only two of three cells. It seems to have worked. The battery had been left unused and not properly in storage for about two years (again, not a great idea). I charged NiMh for three minutes at 0.1A, then the charger recognised all three cells again and I balance charged the rest of the way.

  4. Alex

    I have two Turnigy 3 cell 5.0 lipo batteries that have been stored for around 2 years. They were charged up using the storage setting.
    The cells on one of the batteries read 0.0, 6.9 & 0.0 …the other battery is similar.
    Would I be right to say not to even bother trying this way of charging as they have been left too long?

    1. Oscar Post author

      Check with a multimeter, if the cells read 0V then it’s probably no good!, discharge it competently and dispose it.

  5. FotoAmg

    I have a smaller board TP4056 charger which can regenerate cells.
    I use it on the balance plug and regenerate cells one by one.
    If the cell voltage is below 2.85 volt the charger will charge with about 80mA max, but now I am facing a big challenge. My drone lost and I found it 46day later battery was plugged in for 46days and it was at zero voltage for more thena month :( the battery is brand new I only used it once before Infinity Graphene 70C 1500mAh and did not get any hit or deformation in the crash and not puffy so no signs of externel damage.
    I put fist cell to that regenarator ahd waited now 4 hours, no heating at all, but voltage is still at 0.6V :( no way to get them back?

  6. Andrey

    Hi everyone

    The overdischarging may lead to formation of Internal short circqit.
    See for exaple the following study:

    As i understand the probability of short circquit grows at elevated temperature (i.e fast. charge or discharge). More over such batteries may be more subseptible to mechanical impact, even at transportation.

    So if you wish to use such batteris, you must take triple care.

  7. Mario

    You should add a disclaimer at the top that this only aplies to recently discharged lipos, within a few hours.

    Once the lipo discharges the chemicals in the battery start creating byproducts that cuase the internal resistance to go up fast. You should have a multimeter to check resistance frequently in the battery before, during and after trying to revive it.

    1. Bobby Shaftoe

      Can you please give (*burn the house down disclaimer’d) insights as to the impedances one can expect (or should look for) when testing batteries and individual cells. Also, do you have insights into impedance mismatch across the cells of a battery?

      -We grow The Google, it’s our baby, to train it well.

      Bobby Shaftoe

  8. Eugen

    Great! Thank you. It worked for me too. I used ~ 1/10 C current and leave it for ~1 minute. It brought my “dead” cell from 1.9 V to 3.2V. And now i can charge it with the normal LiPo program. Great! Thanks again.

    1. Eugen

      Now, a few month after i did the “revive” on my battery, i used it one and then i charged it for storage. All looked good at that time. Today, when in borugh the LIPO pack to use it , found that the “dead” cell is dead again at 0.6V. Thus, it looks the dead cell is not truly revived and is just a momentary solution. And by the way, this battery performed way poorer than another good one.

  9. Adam

    Hi Oscar,

    I also use a Turnigy Accucel 6. I am curious how you charge multiple batteries with it. I am flying now with 3S 1300mAh batteries and charging them one by one can take a lot of time (not to mention I don’t leave them unattended, they are always in eyeshot when charging). I have seen parallel balance boards — is this something that would benefit me? It looks like the charger can pump out enough amps to charge more than one at a time (I am charging 1300mAh at 1.3A) but I am not sure how to safely hook them up and determine the charging voltage (1.3A x number of batteries?)

    Any help you can provide would be greatly appreciated. I absolutely love your blog, you cover the big stuff as well as the little stuff I run into like broken balance plugs, etc. You are a tremendous resource for RC flight information on the Internet. I just wanted to say you are very much appreciated for what you’re doing.

    1. Oscar Post author

      Hi Adam, thanks for the kind words!

      I use a parallel charging board, and I wrote something on Parallel charging before:
      Parallel charging Guide

      I recommend getting a board that comes with fuses for extra safety!
      for example like this one.

      regards, Oscar

  10. PilotPatch

    Great blog, has helped me with so many things to do with multi rotors. I have done this twice with my tx battery (i know stupid!) and now the cells are unbalanced and one cell won’t hold charge. Does this mean the lipo is at risk of fire? I have had previous fire with lipo charging and nearly burned the house down! Just want to be sure now with this unbalanced lipo or should i just replace? btw keep up the good work.

    1. Oscar Post author

      Hi PilotPatch, all over-charged Lipo are not safe, not to mention to you over charged it twice! My advice is to replace it, and dispose the old lipo safely :)

  11. Federico

    I agree with you, if you apply a constant current charge (I think 1/5 C is good) you will recovery your battery or know if is dead. For a demostration of own (built from scratch) hexacopter we left in the stand of a contest, I went to the stand (after a inauguration of the contest) and the lipo was dead (and very inflated), I wait three days to deflate the lipo and chargue manually, I need to test the performace of the Lipo (4S 3.7 Ah) to check if the lipo has the required characteristics to maintain our UAV in the air, I think I build a circuit to do that.

    1. Oscar Post author

      What I found was, once the lipo has been over-discharged, the cells tend to be unbalanced, even “balance charging” cannot fix this. Happens to me a few times now, although these Lipos are still usable, but the flight time is somehow shortened…

      good luck with your DIY circuit!


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