Bring Dead Ni-Cad Batteries Back To Life

Are you tired of having your Ni-Cad batteries that refused to charge and simply die?

So what do you do with them when they die?
Just throw them in the trash - which harms the environment?
Or just take them to a recycling facility for them to be recycled?

Well, here is the best solution, bring your dead batteries back to life that can save you a chunk of change - By zapping them!
Here is one great instructable, Revive Nicad Batteries by Zapping with a Welder. Of course, you will need a welder, and not many people has one... So I came up with this idea that almost anyone can build!

UPDATED: This instructable has been featured in hackaday!

DISCLAIMER:
This instructable involves hacking a device that operates on 300 volts and can be dangerous if not handled correctly. So, I am NOT responsible whatever happens to you using this information.

Step 1 So, Why do Ni-Cad batteries die?

Why do Ni-Cad batteries die?

They don't exactly 'die', it is the sulfur crystals that is causing the problem.
The crystals are formed and begin growing caused by:

• Overcharging the cell
• Leaving the cell in the discharge state for a long time
• Memory effect
• Being exposed in high temperature

After the crystals has begin growing inside the cell, it eventually touch both ends of the cell terminals. This shorts out the cell and preventing it to be recharged again...

But, the good thing is the sulfur crystals can be easily destroyed, by putting a hefty surge current through the cell... This vaporize the crystals and the battery should be good as new again!

Comments

[luig]

hey could this be used on bigger batteries eg. NiCd rc batteries 7.2 volts.

[timmartha]

Back in 1992 when i first recived my ham radio ticket My instructor told my class that you can strike a rechargeable battery with a car battery charger 15 times and it would bring most of them back to life. I have sucsesfully done this many times. All have come back to life. I hope this helps.

[bricabracwizard]

I took your advice and used a car battery charger - it worked a treat!

[Plasmana]

You mean short out the battery 15 times with a car battery?

[timmartha]

Yes. Put the pos from the car bat to the rechargeable battery pos, (using jumper cables) then strike the neg 15 times. Do not hold it to the battery just strike it. If you hold it to long it can explode.

[Plasmana]

Ahh okay, I have been told that is it very dangerous to even strike an ni-cad battery with an car battey, I guess they are wrong :P

[bricabracwizard]

I think he meant car battery charger, not the battery itself. This works I used it to bring back an old dead cordless drill.

[timmartha]

What happens over time is the polarity in the batterys revers and this will realign them. After you strick them put them in a charger for the length of time it would take to charge them. Glad that i could help.

[Plasmana]

Thanks for your advice, I will try that when i get more dead batteries :-)

[matstermind]

do you know if that would work with electric scooter batteries?

[timmartha]

As far as i know it will only work on any 1.5 or 1.2 volt batteries. It may work up to 6v small ones but not sure.

[matstermind]

ok, thanks

[pteranosaur]

Still looking for an answer to whether or no this works with NiMh batteries...promt response appreciated !!!

[bricabracwizard]

There is an answer of sorts by Unit042 above to zack247's question Jan 6

[dmcdonell]

Anybody with success restoring Ni-cad batteries live in the Buffalo, NY area? I would pay to restore a Craftsman power tool battery, let me know, [e-mail].

[codongolev]

if I can track down a disposable camera (I think we have a few from when we cleaned out my grandmother's house), I'm totally doing this to my roomba's battery. it'll save me 25 bucks. (I believe, based on others' stories, that the first battery on the positive side is usually the bad one [they're in series]. however, I'll probably zap all of them just in case.)

[codongolev]

alright, folks. here's what just went down. I was thinking about this instructable, and I really wanted to do it. however, the only disposable cameras in the house were ones that my mom was keeping for some reason, and I'm sure it wasn't for me to take them apart. so I thought about it a while, and I remembered playing around with this AC adapter (that's a pretty old instructable, by the way, so keep in mind if you decide to read it that at the time I was still around middle school/high school freshman age). I thought, "that produces high voltage!" so I tried it. my setup was three nine volts in series to create 27 volts, which was then fed backwards (as per the instructable) through the transformer, then over to the battery. by the way, you can't just connect the nine volts then shock the batteries. to create the high voltage pulse, you have to attach the battery to the transformer, then repeatedly connect and disconnect the batteries so you get a spark. otherwise there will be no flow and you'll be wasting your time.

thought I'd share this, as it was very helpful to me (ran my roomba today for about an hour or so, so I'd say it worked especially seeing as before it couldn't even make the startup noise).

[middlenamefrank]

Nice 'ible, I've been doing this for years to bring NiCad batteries back to life (and no, it doesn't work on other chemistries, like NiMH). Usually I just turn on my 12V power supply, which charges up the output caps, turn off the power supply, then quickly zap the battery with the stored charge in the output caps. 12V is plenty when backed up by nice big caps (like on the output of most power supplies).

Don't think your batteries are going to be "good as new" afterwards though. Yes, you can get some more life out of the battery, but I've found they never have the same capacity afterwards (apparently it does some irreversible damage) and it only works a few times on a battery before it's gone for good. For this reason, I don't like to do it on a battery from a multi-cell pack -- then you just wind up with a weak battery in series with stronger ones, which is doomed to be overworked by the stronger cells and will die very soon anyhow.

[azmatanwar]

Can we use this trick on 12 V car battery??? regards.

[MandingaRes]

Excelente!! Gracias por compartirlo.
Saludos.

[aduy]

i just made this instructable about soldering onto batteries http://www.instructables.com/id/Soldering-Directly-Onto-a-Battery/
and i saw this it looks very interesting. will this work with multi-cell batteries, like those from cordless drills, rc cars, and nicad laptop batteries?

[sasrf]

an idea !! would it be possible for electricals in a domestic fluorescent tube lamp to be modified to supply the high voltage ?? it's just an idea, I am not an engineer, maybe someone can comment !!

Thank you .....
sasrf 04/03/11

[craneum]

or how about a laptop or pc power supply? Most laptop ps are 12-20 volts and a Pc ps supplies 5v and 12v.
Only thing I'm wondering is amps... seems like thats the key to the whole thing. Perhaps for single 1.2v cells it would be fine but for a larger bank of cells you may need something that supplies 30+ amps when it delivers the voltage? You know they always say its not the volts that kill ya, its the AMPS.

[Shaji47]

It is a nice tip..... but an disposable camera is not available in our village. How to make that high voltage circuit? lol, hlep me please....

[techno guy]

So the negative of the cap goes to the negative of the battery and same with positive?

[m1sterb0b]

Now, I've done some researc hof Ni-Cad batteries and some on NiMH batteries and I still have yet to figure something out. a NiCd battery is a dry cell battery. Which means that the only "chemicals" involved here are Nickel and Cadmium. When the cell is fully charged the cathode is composed of Nickelic Hydroxide, it will either get +3 or +4 (lose 3 or 4 electrons) and become either NiOOH (+3) or Ni(OH) (+4) and When one connects a load to the cell the anode is oxidized and the cathode is reduced. Electrons leave the anode where the cadmium is oxidized and forms Cd(OH) , plus 2 free electrons. These two electrons go to the cathode where they reduce the Nickelic Hydroxide to form nickelOUS hydroxide or Ni(OH) (where the nickel has a charge of +2). In all the stuff I've studied show that theres no way for sulfur (S) to exist in a NiCd battery. The only chemicals I've noticed are nickel (Ni), cadmium (Cd), oxygen (O) and hydrogen (H). If I'm missing something if someone could shed some light on it for me, I'd appreciate it. but as far as I know, and have seen, no sulfur exists in a NiCd battery! (to cite a source, one place i copied and pasted info from was: http://www.wppltd.demon.co.uk/WPP/Batteries/Chemistry/chemistry.html)

[Unit042]

I think the author of this instructible confused the NiCd whiskers with sulfation in lead-acid batteries (a similar concept, old battery not taking a charge, zap it, and it lasts a bit longer). The sulfur is not, to my knowledge, involved in NiCd batteries in any way.
A lot of electronics beginners on this website like to use disposable cameras without understanding what they are playing with. :(

[jerry0]

I've been zapping nicds for many many years and it works about 90% of the time.

[Unit042]

I was not doubting the results or workability of using a disposable camera to zap batteries to make them work again. What I meant was, NiCd batteries don't have sulfur in them. Lead acid batteris do.
NiCd batteries do grow crystals, but they are not sulfur, because there is no sulfur in NiCd batteries.
Lead acid battery plates get covered by sulfur (sulfation), because their electrolyte is sulfuric acid.
Both are typically zapped one way or another to revive them, and it may or may not work, depending on your setup. Mine have often worked.
Similar concepts, incorrect wording in instructible.

A large number of people on this site who do not have the electronics knowledge needed to A: build a high voltage power supply, and B: keep them safe from high voltage, oftenly use disposable cameras as a high voltage source. Not that their safety is my problem, but still....

Sorry for any misunderstandings or ambiguities.

[buteman]

It's certainly the case that NiCd's do not contain Sulfur ( which is an insulator anyway and would not cause a short.) But it is lead sulfate, not sulfur which causes the problem in lead/acid batteries.

[zack247]

i have the same question as pteranosaur,
Does this work with nimh batteries?
or is there a different chemical composition in nimh's that makes this not work?

[Unit042]

Yes, they are slightly different chemically, but they are still pretty close. Probably close enough for this to work. If you try it, be sure to post the results! :)

[Schober]

Can this be done with batteries larger than AA's? Say, something like a 7.2v or 8v r/c battery or would you need to increase the power?

[Lee Wilkerson]

The problem with the higher voltage batteries is the fact that they are comprised of quantities of AAA, AA, C, or D NiCD batteries (A fully charged NiCD cell is 1.2V. Ex: 6 x 1.2=7.2V). That in itself is not the problem - the problem is that those cells all deteriorate at different rates. This means you MUST disassemble the battery packs or at least compromise the packaging to get access to each individual cell. Once you have done so, check each cell with a voltmeter. You will likely find one or two cells in the pack which either have very low or reversed voltage. Those are the ones which you will need to address.

~/Lee

[zack247]

hi, you seem to know what youre talking about...
will this work with nimh batteries? i have 12 of them and if i can do this to them then i can use them again.

so does it work on nimh's?

[Plasmana]

That will burn out the transistor...

[Schober]

Is there another setup that would make it possible to zap a larger battery in a similar manner?

[Plasmana]

This would probably help.

http://www.instructables.com/id/Revive-Nicad-Batteries-by-Zapping-with-a-Welder/

[drbill]

I did an 18v drill motor battery that was dead as they come with an auto transformer and a fully buffered bridge rectifier. I ran it up to 40vDC for 3 seconds two times and the thing was like new !
We call it "Blowing Off The Wiskers".

[backscan]

I have some battery marked Ni-Mh  will this work on them? Also can I just use my mothers stun gun? It puts out 150k volts. If your not sure I'll just wait to a better day and run a looooong set of wires to the battery outside : )