Can Ni-cad batteries be saved?

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  • Can Ni-cad batteries be saved?
  • mk1fan
    Member

    A the ni-cad batteries of some of my ‘less used’ cordless tools aren’t holding their charge for long at all. They haven’t seen a lot of use at all.

    Boefore I stump up for new batteries, does anyone know if they can be revived and how to do it?

    nickf
    Member

    With counselling and the help of the Lord, I’m sure they can be helped.

    But they have to want to be saved.

    Premier Icon cynic-al
    Subscriber

    Never heard of a method for saving them.

    Assuming you are fully charging & discharging them then I think it’s “game over”.

    large418
    Member

    there is meant to be a way. Never tried it myself but keep meaning to. It involves shorting the NiCad across a car battery for a second a few times. Sounds quite risky hence my reluctance……

    Try googling for nicad battery saving or something like that. Lot’s of people are selling the instructions on ebay for a couple of pounds, or you can find on some of the powertool forums or DIY forums a link to a site where some kind soul has pasted the instructions.

    All the usual disclaimers apply if you do try it though……

    snaps
    Member

    The radio ham guys used to do it by flicking the leads of a higher voltage battery across the Nicads but as large418 says you need to know what you’re doing 😯

    Premier Icon AlexSimon
    Subscriber

    Isn’t that for when the charger doesn’t recognise them though – i.e. they have been completely discharged?

    I find that Ni-Cads still respond to the fully charge, fully discharge method. i.e. fully charge them, then leave something rapidly discharging them until they are dead – try and leave it a few seconds and they try to use the last drop of power, until you really can’t get any more out of them. Then fully charge them and repeat 3 times.

    Premier Icon maccruiskeen
    Subscriber

    It might depend on whats caused them to lose their umph. Repeatedly part-charging them upsets them, they acquire a sort of memory and won’t charge past that point. Storing them part charged/uncharged does for them too, in that case its to do (if I remember right) with crystals growing between the elements inside the battery and causing lots of little shorts, so that the battery self-discharges. Although whether the cures for both those instances is the same I’m not sure.

    What make of drill is it – NiCad battery packs are a lot cheaper than they used to be, and there are aftermarket one for some of the bigger brands, but not all brands are available still.

    ni-cad batteries stop working because of crystals forming between the plates (im told) this can be fixed by putting an excessive charge through them for a very short time.

    what you need is a dc supply much higher then the voltage of the battery, such as an arc welder. there is a sort of technique where you kind of strike at it as if striking a match. maybe 2 or 3 times. the battery must be flat at the start.

    obviously this is very dangerous and i therefore dont recommend anyone does it but i have and it did work

    here watch this – http://www.youtube.com/watch?v=ENmAJ2GOAMY

    edit before the stw pedantic police turn up that is a mig but i only have an arc

    Premier Icon leffeboy
    Subscriber

    I’ve tried the applying a car battery across nicads for a very short time before and it does help but not enough to be worth it. Better spending your time finding a cheap source of batteries. If you are a real cheapskate or the batteries are very expensive then I’ve taken car racing packs to bits before as a very cheap source of good tabbed nicads

    i tried it after i google it for instruction ,on a 18 volt that wouldnt hold a charge. i zapped it with 36 volts and left it to cool, recharge it perfect use it every day 😀

    dr_adams
    Member

    have heard it work after using welders on lots of forums… personally would’t dare when they are cheap..

    Premier Icon AlexSimon
    Subscriber

    So did you dare mk1fan?

    mk1fan
    Member

    I don’t have a welder to hand but can do the charge – discharge cycle thing so will try that for the 14.4V ones.

    I’ve found a 9,6v replacement for £25 so may just get that for the 9.6V one.

    Premier Icon maccruiskeen
    Subscriber

    A 9.6 will be may not actually fit, it’ll be physically smaller than the current one you’ve got

    mk1fan
    Member

    The 9.6v replacement will be too small to replace the duff 9.6V battery?

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