Bringing dead nickel-cadmium batteries back to life

Electronics / DIY electronics 102 616 11

Very often, nickel-cadmium batteries refuse to charge at the moment when it is so necessary. They are especially capricious and do not tolerate neglect. They may fail for the following reasons:

-Recharge.
-Were in a discharged state for too long.
-Exposed to excessively high temperatures.
-Temporary effect.

Bringing dead nickel-cadmium batteries back to life

But it's not that scary. And at least half of all batteries can be brought back to life and made to work again. To do this, you can assemble a recovery installation from an old camera. It just has a high-voltage generator with a storage capacitor. The point is to “puncture” the battery with a very high current pulse, which will “stir up” the internal processes and force the battery to take and release its charge again.

Will need

ni-cd batteries.
Old film camera with working flash
Wires
Switch.
Button.
Battery holder.

The process of creating a device for restoring ni-CD batteries

We disassemble the camera and remove the cover.

We separate the board from the case.We solder pre-tinned wires to the button that fires the flash.

And then we solder these wires to the switch.

This switch will be needed later to completely discharge the internal capacitor with the flash.
We also solder wires to the output of the storage capacitor. Before this procedure, be sure to make sure that there is no charge on it - shorten it with a screwdriver, for example.

Next, we solder these wires in series with the button and the battery holder. The plus from the capacitor goes to the plus of the battery.

The recovery process itself

So, we insert the batteries for power into the board holder - the converter will be powered from them. And we insert the ni-cd battery into the holder for restoration.

Reconditioning process of nickel cadmium batteries

Then turn on the board's power. Usually you can hear the squeak of the transformer operating. You need to wait until the capacitor is fully charged (for this, most models have a special Light-emitting diode). As soon as everything is charged, press the button connecting the battery and capacitor circuit. You will hear a strong click - this is normal. It even happens that the button contacts may stick.
You can repeat this procedure 1-3 times in a row and then immediately put the battery on charge.

Conclusion

As I already said, most practically dead batteries can be brought back to life. Be careful: the capacitor charges up to 300 V, which is definitely life-threatening.
You should also not use very thin wires, since the peak current can reach 1000 A, because there is practically a short circuit.
After all the procedures, close the flash switch and turn off the power to the entire board.
Original article in English

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Comments (11)

#1 Guest Valery Guests 7 June 2019 21:12
13

Why do you need a camera? You can simply charge the capacitor from the mains, turn it off, and then discharge it through the button.
- Answer
#2 Guest Vitaly Guests 8 June 2019 15:17
2

The camera is needed because the article is intended for people who are superficially familiar with radio engineering, for their own safety, because it contains a ready-made circuit that increases direct current. It’s still very easy to find an old camera; it’s probably lying around idle at home or someone you know.
The proposal to charge the capacitor directly from the network is very dangerous. Electrolytic capacitors should not be simply stuck into a socket, as they may cause injury.
- Answer
1. #3 Alexander Stepano Guests 22 March 2020 13:13
  5
  
  Why plug the capacitor directly into the socket? A current-limiting resistor is also needed through the diode. Everything is easier than using a camera.
  
  Answer
#4 Guest Victor Guests 8 June 2019 19:03
6

I bought a charger for AA and AAA batteries on Ali; even ancient batteries (they are yellow in the photo), which are 15 years old and have never been used, were charged. Charging cost approx. 700 rub. If you buy a handful of batteries of both types there, then you can completely abandon the batteries.
- Answer
1. #5 Guest Andrey Guests 18 June 2019 23:51
  3
  
  Don’t flatter yourself, from Ali Akomas come every 5 times with a reduced capacity, tested, measured
  
  Answer
#6 Guest Vlad Guests 18 June 2019 09:07
3

Just a miracle :) What if the Akum has already lost capacity due to the number of cycles. Will it be like new too?
- Answer
#7 Tolya Guests 25 June 2019 18:02
8

Guys, don't be stupid. Nothing good will come of this.
- Answer
1. #8 ILYA Guests 3 July 2019 12:09
  2
  
  I agree, at current prices for batteries, it is not very profitable to restore, it is easier to buy. But as information for general development, it is not bad.
  
  Answer
#9 Guest Andrey Guests 23 July 2019 21:08
9

I bent about 1000 amperes.
- Answer
#10 Guest Pavel Guests 11 April 2020 12:05
6

The fact that Ali... may have batteries with a lower capacity than stated, yes!!! But the goods in the store are also not American, German or Japanese.
- Answer
#11 Victor Guests 23 November 2021 16:40
2

Guest Andrey
Don’t flatter yourself, from Ali Akomas come every 5 times with a reduced capacity, tested, measured
It depends on which one to buy. I have already bought analogue little fingers 2 times. What is stated is what is there. The quality matches the price, and it doesn’t hurt to read the reviews. And under no circumstances should you peck at aa and aaa with a capacity of 3000-4000 mah.
- Answer