Introduction: Bring Dead Ni-Cad Batteries Back to Life

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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!

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!

Step 2: What You Will Need for Battery Zapping...

I recommend using capacitors as they give a powerful pulse discharge.
Other power source like car batteries and welders are not a good option. Because as they give out a continuous discharge, the wire can be accidentally get welded to the battery terminal and cause them to over heat and possibly explode... You can use car batteries or welder, just be careful what you are doing.

The capacitor type you should use is somewhere about 100,000uF 60v. Unfortunately, that capacitor with an extreme ratings are just way too expensive...

So in this case to avoid paying a chunk of change for a big capacitor, I use disposable flash camera's capacitor instead for this project. Why? Because they are suitable for pulse discharging, and best of all, they are FREE! But they are more dangerous...

So, what you will need for this project are...
  • A disposable flash camera
  • Dead Ni-Cad batteries
  • Wires
  • Battery holder for the dead Ni-Cads (You can use size AAA, AA, C, or D, depending what battery you want to zap. I am going to use an AA battery holder for this instructable.)
  • Small switch (I used a slide switch)
  • High power switch (I used a push-button switch)

You can get free disposable flash cameras from photo developing places like Wal-Mart and such.

And for the tools, you will need:

  • Soldering iron (You might be able to get away with out doing any soldering by twisting wires in place.)
  • Wire cutters
  • Wire strippers
  • Flat head screwdriver
  • Pliers

Right, hopefully, you got everything, so lets get to work!

Step 3: Slaughter the Camera!

Give a general description of the StepNow this is going to be a fairly dangerous part, open up the camera and get the circuit out safely without getting shocked by the capacitor...

(The capacitor in the camera is a large black cylinder thing, it is used for making flashes for the camera.)

First, pry open the camera's case apart with a flat-head screwdriver or just use your hands if you like, but you are more likely to get shocked by the capacitor.
After you taken the camera's case off, discharge the capacitor with a insulated screw driver, and you may get a big loud spark, and after that, the capacitor is discharged... (Use a screwdriver you hate so much, because a fully charged capacitor will leave a scar on the metal part of the screwdriver!)

Great! You had done the dangerous step on this instructable! (Some people say this is the fun part of the instructable because you get a loud spark from the capacitor.)

Step 4: Remove and Add Switch

After the camera's circuit is removed from the frame, we need to remove the surface-mounded charge switch and add an external switch. Doing so, you will have easier control of the circuit and less likely to get

Remove the top bit of the charge switch. It will have some tape on the top, so it shouldn't be too hard to remove.

Then solder two pieces of wire on both exposed metal tabs. And solder a 'new' charge switch onto the other ends of the wires.

Step 5: Add the Battery Holder an the Switch

Then we need to solder the battery holder and the high power switch together with the black capacitor.

Solder the black wire of the battery holder to the lead of the capacitor that is the closest to the grey stripe.

Solder a piece of wire to the other lead of the capacitor.

Then solder the push-button switch to the red wire of the battery holder and the other wire.

Also, the battery holder you just added, that is where you put the dead Ni-Cad battery to zap them.

Step 6: Insulate the High Voltage

Okay, you are almost done! All you need to do is somehow insulate all the high voltage parts...

You could put it in a nice project box... But I don't have a project box available, so I just put tape on all of the bare metal parts and taped the bottom of the camera's circuit.

And you are done!

Step 7: Zap the Hell Out of the Battery!

To zap a dead Ni-Cad battery back to life, put the Ni-Cad battery into the 'zapping' battery holder and a good alkaline battery into the battery holder on the camera's circuit.

The turn on the charge switch and wait for the neon/LED to glow. When it starts glowing, push the push-button switch and you may hear a loud 'POP'. That is OK for it to pop, it shows the battery has been zap an it is alive! But to be sure the sulfur crystals are really vaporized, zap the Ni-Cad battery one more time...

After zapping the Ni-Cad battery, charge it in its charger to really get it working again.

This works for me very well, I hope it works for you!

If you have any questions, or need help, or found an error, or anything, make a comment!
I like comments! :-)

Also, could you spare your few seconds on voting this instructable? Please?

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