Revive Nicad Batteries with a Welder

WOW! Not for the faint of heart.

why mig welder charge the battery with 12 volt charger for some time (before it become hot)

Use a mig welder not a good idea!! Average max output volts about36, minimums around 18 Volts will deliver a hefty continuous current into the cell shorted dendrites or not,you might want to wear goggles and a hard hat.

Best method is a reasonably high capacity capacitor charged to 90 volts approx discharge through the cell via an SCR to save burnt contacts etc. Hit it as many times as is reasonable if cell volts start to pick up it might come good again.

Back in the 70's when NiCd's were expensive, we used a car battery (12Volts) to flash the half dead NiCd cells back to life...

Worked a treat!! But I wouldn't do it for a battery pack as in the video, the good working cells in the pack must get a nasty shock having multi tens of amps banged through them, just to get to the one cell that needs the amps to burn away the dendrite crystals!!

As others have said, not to be tried without safety equipment - besides the explosive risk there is the danger of cadmium particles being released as well...

John.

At message text says "zap tired old Nicad tool batteries back to life with a mig welder"

'mig' is usually short for metal inert gas, a particular type of welder that's generally used for stainless steel or aluminium, that deposits metal during the welding process.

I do not think that a mig welder results useful to the proposed object.

I should better use a regular arc welder.

Greetings

The use of a mig welder allows a variation of the output voltage since it is a "CV" constant voltage power source. The speed of the wire into the puddle determines the amout of current and penitration during welding.

A conventional stick welder is a "VV" variable voltage power source, thus the "OCV", open circiut voltage, is typcally high, approx 60 to 90 volts DC. This may cause an explosion of the battery due to the high voltage on an 18 volt battery.

The mig is definitly more desireable due to the control of the voltage.

Sure! you are correct.

Sorry, I don't think from that point of view.

Merry X'mas and Happy New Year.

Carlos

The best way to revive single cell 1.2 ni cad ni mh

Use a coarse metal file and use is as a switch.

the process:

1- if in a battery pack

a- identify the bad cell by first recharging than take a voltage measurement to identify the bad cell

B- use 2 wires with alligator clips on each end

one to positive one to negative of the cell

C- connect the cell's positive (+) to to a 12 or 24 volts DC source of any kind

D- connect the negative (-) of the power source to the coarse metal file

E- now the trick -> brush the negative (-) lead of the 1.2volt cell on the metal file

you will see a lot of sparks

what this does is frequence the high voltage into voltage/current spikes and vaporizes the the specs that was shorting the cell,

I have done this since 1990 with geat success, do not do this more than 4 times rapidly.

the battery will actually show a charge after complition

Hope this help

Let me know of your successes

regards

You obviously haven't watched the video or read the posts on here...

That's exactly what he does in the video and what I said we used to do in the 70's...

Please keep up! John :-)

Hello Electroman

I did not find the reference you mentioned please let me know of the link for the video

Thanks

During WWII when spares for radios were almost impossible to source we used similar techniques to get short circuited electrolytic capacitors back in service.

Hi Stclair... I didn't mean to sound rude...

The video link is in the first post just above the 'Digg this' and 'Delicious' buttons//

If someone knows what those buttons do tell me eh??

John.

Hello Electroman

Got to see the video interesting, and I did read the posts before I commented/shared my metal file switch approach, what method did you use to switch the 12 volts into the dead cell ?

Oh in the Marconi labs we just used to use a wire to flash against the battery terminal...

Could get quite worrying when the wire welded itself to the battery and we had to frantically pull it off before an explosion resulted!!

John.