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Rejuvinating Ni-Cad batteries

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  • Rejuvinating Ni-Cad batteries

    Supposedly there is a technique where you can give your old Ni-Cad batteries new life. Basically it involves draining the battery totally, putting it in the freezer for an hour, then tapping on the bottom of the battery with a screwdriver handle, bring it back to room temperature and then recharging fully. Any one had any experience with this? It appears to work as we have tried it with a couple batteries where I work.

    The story is that Ni-cads have a crystalline structure and the crystals tend to grow together and that is how the battery develops a memory. Freezing and then tapping the battery case helps break up the crystals so that they will then take a charge again. Don't know if it is true but that is supposed to be the deal. Any battery experts on here?

  • #2
    Re: Rejuvinating Ni-Cad batteries

    there was some info on the net by zapping the battery's with a wire feed welder, and said to do the same thing (in breaking up the crystalline structure), (I tried using my commercial battery charger, it worked for a little while but by no means was it a cure or restored them), I think when they get to where they will not hold a charge there is little hope for them,

    I suppose by putting them through some hot cold cycles and vibrations may help for a short time, but I really do not think one can rejuvenate the cells.

    If there was a way of truly remixing/replacing the chemicals in the battery and repacking them back in the case then there may be a way, but I do not think there is a safe DIY way of doing that, and replacement is probably the better option,

    for years people have tried to come up with ways of rejuvenating lead acid batteries (besides limited success of the pulse chargers), I do not think there has been much progress in the sulfating of lead acid battery's, and they have been around for many more years than Ni cads, (at least in normal use). and if there was a easy way of rejuvenating them with ease, some one would have a machine and for $XX you could take your batteries to some place and place them in the unit and it would zap and shake and restore the battery if it was easy or simple, there would be much money to be made in the process like that.
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    • #3
      Re: Rejuvinating Ni-Cad batteries

      OldHunter, I don't know if I like the sound of that idea. I too remember hearing the odd thing about "battery rejuvination" here and there, but I think they're mostly urban legends and old wives' tales. With something as potentially dangerous as a battery, some DIY solutions might be best to not be tried. (Especially the "zapping with a wire welder" idea that BHD mentioned - that scares the begesus out of me! I can just foresee a battery cell potentially exploding/bursting with that!)

      I myself have gone with the freezing and tapping route on both regular AA's and rechargable ones, but those results were varied and iffy. If I remember right, I might have got a little bit more out of them.

      But, I know that generally, the cells in power tool batteries are different from other run-of-the-mill batteries. I don't know if following this route could be dangerous - if it could cause damage to the battery itself, if it could cause undesired/dangerous operation of the tool, etc., etc.

      We have a few guys on here who are good with engineering specifics and battery chemistries and the like - maybe they can chime in as to whether or not this would help or work.

      But for me, rather than going through all that hassle, if it's not a battery that's covered by a warranty and/or LLSA, I'd look at getting a battery refurbishment done, where you can get all new cells installed in your battery - its a very economical way to get it done.


      • #4
        Re: Rejuvinating Ni-Cad batteries

        you are talking about "ni-cd zapping". It's been around for decades and there is a ton of asses on ebay selling ebooks with instructions for $2.99-14.99, which can be found online in abundance, for free.

        As BHD said, the principle is to blow the "dendrites" with high current. You take the battery apart and zap each cell with a car battery or a welder. The problem is, when the dendrite melts it burns the hole in the membrane inside the cell. Zapping is a very short term fix and is totally not worth it.

        As for lead-acid batteries, there is a way to restore them and a lot of progress have been made. You can learn how to make one or buy one here:


        • #5
          Re: Rejuvinating Ni-Cad batteries

          Okay, I have a question for you DRC-Wartex. I know this is a thread about Ni-Cad battery rejuvination, and my question relates to something different regarding lithium-ion batteries, so I've started a new thread here: