Comments on: Zap new life into Ni-Cads

By: LR

LR — Tue, 20 Oct 2009 15:04:36 +0000

Oops, with the camera I guess you don’t have to worry about pulling the connection apart. But you do with a 12V battery or a 12V car battery charger.

By: LR

LR — Tue, 20 Oct 2009 15:01:46 +0000

If you do this, be ready to PULL the connection apart instantly as it can weld itself! For a pack with a lot of cells, reverse the polarity or, if it has some decent voltage in it, just short it. I’ve never seen an explosion but I suppose it’s possible. Then again, I never let it go on as much as one second.

The batteries will NOT be like new, but they may work for quite a while. I do this for my cordless phone packs, as they go bad often. In that case, I have to be careful to do one cell at a time so as not to blow the built in fuse that’s in the pack.

The use of a disposable camera is a neat trick, though.

By: Ronnie

Ronnie — Fri, 28 Nov 2008 14:44:02 +0000

As long as the cells in the pack are NiCd you should be able to try this with a drill pack if you open the case and zap each cell individually. Doing the whole pack wouldn’t be a good idea since some packs might take more of a hit than others depending on their state. You wouldn’t need to break the welds on the cells, just contact each cell for zapping individually and reassemble the pack.

By: Adam

Adam — Fri, 28 Nov 2008 13:16:26 +0000

@ first poster: learn how to spel. can’t stand seeing “pracicle” any more. and stop advertising your site.

By: Ed

Ed — Fri, 28 Nov 2008 08:48:40 +0000

A more professional method which I’ve tried: http://www.tunecharger.com/

This guy took pulse charging to more extreme conditions and managed to make it work with many battery technologies. I’ve used this for portable solar packs with great success, as it lends itself very well to unstable power sources.

By: h_2_o

h_2_o — Fri, 28 Nov 2008 02:57:17 +0000

most drill battery packs are made up of sub c’s of some sort. they could be nicd, nimh, or lithium. I know nicd’s can be revived sometimes, it really is hit and miss. DO NOT try that with lithium ion battery’s you will regret it and end up hurt. i have never really tried it with nimh so i can not answer there. however there is a larger issue with zapping drill battery packs, they are normally packs that are normally spot welded so rebuilding them if you tear them down can be a pain. also getting them hot is not the best idea in the world either but that is a discussion for another day.

By: atrain

atrain — Fri, 28 Nov 2008 02:54:15 +0000

So I decided to try this out. I checked my target battery for polarity, but found it had 0V. I plugged it into my charger, and it ended up shorting out the charger, blowing up a resistor and melting parts of the case and pcb.

Is this battery in too bad condition to be recovered?

By: atrain

atrain — Fri, 28 Nov 2008 01:58:18 +0000

I’ve heard of zapping NiCd’s with HV before, but never with high-current sources (eg: car batteries)
Can you use a 12V car battery to zap a 12V drill battery back to life, or does it have to be a larger voltage? (like in the case of normal charging)

By: space

space — Thu, 27 Nov 2008 23:16:45 +0000

this method ( high voltage pulsed zapping ) is usually used to revive lead-acid car batteries that have lost capacity and power but still have good voltage. have no idea if it will work on nicd batteries, but if you want to try to revive car battery do it outside, and please use the eye protection gear. batteries are sealed containers and they can explode if overheated or overloaded.

By: O Mattos

O Mattos — Thu, 27 Nov 2008 22:00:28 +0000

This method is for fixing batteries where an internal piece of metal “dust” shorts between the anode and the cathode. A small high current “zap” should be enough to burn out that particle meaning you can now go ahead and charge the battery.

You shouldn’t do it for more than about 2 secs, certainly not enough for the whole battery to get noticably hot, since then yes, like h20 said it could explode.

By: BattGuy

BattGuy — Thu, 27 Nov 2008 21:45:00 +0000

Actually, what’s being done here, AIUI, is the burning out of the dendrites that form in NiCd batteries (and *only* NiCd batts!).

Instead of a high-volt source I was taught to use a high-AMP source, like a car battery or other 12V source – anything larger than a housebrick should be big enough. One would then just momentarily (as in brushing a wire to complete the circuit for, like, a ms) complete the circuit where you’d have the + of the BigBatt connected to the + if the NiCd, and the – of the BigBatt connected to the – of the NiCd.

This high-amp short circuit tends to burn out the dendrites that prevent the NiCd from accepting a charge.

Cautions:
Beware hydrogen gas from Lead Acid (BigBatt) type batteries, esp during/after charging them.

When you brush the wire to complete the circuit you’ll get a spark. This is part of the fun.

If the NiCd begins to feel warm then stop immediately.

I sometimes brush a few times, for good measure.

This ‘revival’ process works very well to revive a dead NiCd that won’t accept a charge from its charger. After reviving charge as per normal.

Wear eye protection.

By: D.

D. — Thu, 27 Nov 2008 20:13:54 +0000

This does work, but can give mixed results.
The info in the instructable is a bit off, sometimes the reason a cell is “dead” is due to a tendril of fine metal that forms over time and shorts the cell. Putting a quick, hefty voltage through blows the tendril up (like blowing a fuse), allow the cell the charge normally. But, sometimes the tendril has punctured the insulation in the cell, allowing the cell to discharge more quickly, so a revived pack may hold a decent charge if used quickly, but die much more quickly on the shelf.

By: ngth

ngth — Thu, 27 Nov 2008 20:10:51 +0000

Take note: *** THIS IS VERY HAZARDOUS ***

Zapping or charging anything with a higher than rated voltage is not recommended. And of course, instructables does not actually tell you to take any precautions (e.g. facemask, gloves, etc).

By: h_2_o

h_2_o — Thu, 27 Nov 2008 20:07:45 +0000

well yeah that might be part of my problem, normally i’m good enough that i don’t blow them up, but then again i go a little overboard. normally i just use a dead mans cord and hit it quick. gets the job done and i don’t have to go looking for all sorts of things.

By: cooldemo

cooldemo — Thu, 27 Nov 2008 19:24:23 +0000

For these purposes I always use 12V 7Ah SLA battery. I never had a single cell explode, though you are just supposed to connect it for a fraction of a second, not till it is charged :) And observe polarity …