# Dead Ni-Cad Batteries?



## woodnthings (Jan 24, 2009)

In another thread I mentioned I had 10 old, dead Dewalt batteries and 10 good ones. I remembered seeing a video on You Tube about "battery zapping", that is using a higher voltage higher, current source like a auto battery charger to "zap' the crystal formations inside the batteries that keep it from working. 
So, I searched You Tube and found this method which is even better. I can't personally verify that it works, but it certainly appears so. If it does, it will save you or me big bucks when your battery "dies". I'm gonna try it. :yes:


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## ryan50hrl (Jun 30, 2012)

Let us know if it works


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## Alchymist (Jan 2, 2011)

Did some of this many years ago - when the nicads were relatively new on the market. 

First "repairs" consisted of opening the battery pack, and measuring the voltage across each individual cell. Usually one or two were substantially lower or even of reverse polarity from the rest, and these were replaced with other used cells, and the battery would then charge. ( Battery voltage would not be full voltage, but rather fractions of a volt, but most of the cells would be close. The bad ones were much lower or even of opposite polarity).

Later a fellow tech discovered that a large capacitor charged to 24 to 30 volts and discharged across the "defective" cell would sometimes restore it. Restored cells never lasted as log as a new one, but would work for a substantial period of time. Theory was that crystalline growth partially shorted the battery, and the zap voltage burned off the growth.


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## del schisler (Nov 5, 2009)

woodnthings said:


> In another thread I mentioned I had 10 old, dead Dewalt batteries and 10 good ones. I remembered seeing a video on You Tube about "battery zapping", that is using a higher voltage higher, current source like a auto battery charger to "zap' the crystal formations inside the batteries that keep it from working.
> So, I searched You Tube and found this method which is even better. I can't personally verify that it works, but it certainly appears so. If it does, it will save you or me big bucks when your battery "dies". I'm gonna try it. :yes:
> Revive Your Old NiCd Batteries...! - YouTube


i have done this and it work's some what, it will get you by , but they are not as good as new , they lack some tork after the rej. but can get you some more life , just make sure that pos go to pos and neg to neg.


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## thegrgyle (Jan 11, 2011)

Aw, shucks! I just bought a replacement for one of my drills. I am definitely going to try this out on the old one, and let you know the results.


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## Loganville Tiger (Dec 23, 2012)

I have "_jump started_" my "_dead_" 14.4's for my Milwaukee drill many times. Don't know if the method will work for other brands.

The battery gets so "dead" the charger doesn't recognize it. Get a 9 volt battery and a couple short pieces of electrical wire. Run positive to positive and negative to negative. Hold it there for 30 seconds or so and it will infuse enough juice for the charger to recognize the battery. 

LT


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## thegrgyle (Jan 11, 2011)

Well, I tried it on my one battery, and it seemed to work.... the battery didn't have as much gusto, and I didn't actually use it yet.... I will be this weekend though. I will keep you updated....


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## woodnthings (Jan 24, 2009)

*This one uses a different technique*

But it also appears to work. However there is no proof in this video, other than the voltage shown on the meter.


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## Steve Neul (Sep 2, 2011)

I fixed a battery good last night and will never have a problem with it again. I put it on overcharge and forgot it. Went out to the shop about 9 pm and as soon as I walked in the door, "What is that smell". It appears I brought the battery to a boil. Now I can quit fighting with it.


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## Loganville Tiger (Dec 23, 2012)

Steve Neul said:


> I fixed a battery good last night and will never have a problem with it again. I put it on overcharge and forgot it. Went out to the shop about 9 pm and as soon as I walked in the door, "What is that smell". It appears I brought the battery to a boil. Now I can quit fighting with it.


LOL - Sounds like _my kind'a fix_...... We all have similar stories for different things we have attempted to fix, only to waste time and buying new in the end.....


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## woodnthings (Jan 24, 2009)

*Agreed!*



Loganville Tiger said:


> LOL - Sounds like _my kind'a fix_...... We all have similar stories for different things we have attempted to fix, only to waste time and buying new in the end.....


My local superstore Production Line Tool, had a sale on 2 packs of 18V Dewalt batteries for $99.00 ...I got 2. 
I tried everything from a car charger to 36 V by series wiring 2 - 18V Dewalts that were good and could bring some back to 6 V or 9 V even 15 V, nothing I did fully revived them. Maybe Ryobi batteries are different but I doubt it. Mine were just too "dead" prolly ... sama::gunsmilie:


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## ejgoerner (Dec 31, 2012)

I had a dead 12 volt, hit with a 24 volt truck charger. i put the battery on the charger the lights flashed for a few minutes then it charged and I have been using it for months with no issue


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## Woodwart (Dec 11, 2012)

Can you do the same thing if your Li-ion batteries give up the ghost?


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## Eagleeye (Dec 3, 2011)

I tried the jump start on two 18v. Rigid batteries I had been moving around the shop for two yrs. waiting to recycle. Both now take a charge. 

Thanks for the tip.


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## del schisler (Nov 5, 2009)

Eagleeye said:


> I tried the jump start on two 18v. Rigid batteries I had been moving around the shop for two yrs. waiting to recycle. Both now take a charge.
> 
> Thanks for the tip.


i have done this to my 12volt's and it works, but they don't quite have the power as new but they work ok saves money , if you are not quite ready to buy new . some of the older charger's if the battery voltage is below 3 volt the charger will not work, so if you hit with higher voltage on the battery , than the charger will work


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## Gilgaron (Mar 16, 2012)

Woodwart said:


> Can you do the same thing if your Li-ion batteries give up the ghost?


I don't think you can, the chemistry for why NiCads fail is different.


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