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Electronics => Repair => Topic started by: pcmad on April 14, 2021, 08:43:12 pm

Title: do freezing NiCad rejuvenate them or what would you recommend
Post by: pcmad on April 14, 2021, 08:43:12 pm
do freezing NiCad rejuvenate them or what would you recommend
Title: Re: do freezing NiCad rejuvenate them or what would you recommend
Post by: wraper on April 14, 2021, 08:48:30 pm
Quote from: pcmad on April 14, 2021, 08:43:12 pm
do freezing NiCad rejuvenate them
Why some random action should restore them?
Quote
what would you recommend
Disposing them.
Title: Re: do freezing NiCad rejuvenate them or what would you recommend
Post by: joseph nicholas on April 14, 2021, 09:33:44 pm
Everything wears out, get use to it.
Title: Re: do freezing NiCad rejuvenate them or what would you recommend
Post by: RoGeorge on April 14, 2021, 10:19:27 pm
Ni-Cd rechargeable batteries have memory.  Try a few cycles of discharging them to zero volts then charging, in order to remove the unwanted memorized discharge level.

Another common mode to fail is they grow dendrites internally and short circuit themselves.  This fail mode can be removed by braking the dendrites with a very high current pass through the battery.  It works but soon the dendrites will grow again, so this kind of recovery is not very useful.

NiCd technology was replaced long time ago by NiMH or Li based rechargeable batteries, so long ago that most of the times it doesn't worth trying to recover NiCd.
Title: Re: do freezing NiCad rejuvenate them or what would you recommend
Post by: Monkeh on April 15, 2021, 12:41:19 am
Quote from: RoGeorge on April 14, 2021, 10:19:27 pm
Ni-Cd rechargeable batteries have memory.  Try a few cycles of discharging them to zero volts then charging, in order to remove the unwanted memorized discharge level.

Not on planet earth they don't.
Title: Re: do freezing NiCad rejuvenate them or what would you recommend
Post by: RoGeorge on April 15, 2021, 01:03:11 am
https://www.electronics-notes.com/articles/electronic_components/battery-technology/nicad-nicd-nickel-cadmium-memory-effect.php (https://www.electronics-notes.com/articles/electronic_components/battery-technology/nicad-nicd-nickel-cadmium-memory-effect.php)
Title: Re: do freezing NiCad rejuvenate them or what would you recommend
Post by: Monkeh on April 15, 2021, 01:06:12 am
Quote from: RoGeorge on April 15, 2021, 01:03:11 am
https://www.electronics-notes.com/articles/electronic_components/battery-technology/nicad-nicd-nickel-cadmium-memory-effect.php (https://www.electronics-notes.com/articles/electronic_components/battery-technology/nicad-nicd-nickel-cadmium-memory-effect.php)

Which references my point.

You need consistent charge/discharge cycles to see the memory effect, far more consistent than you'll see in consumer use. It was discovered on satellites.
Title: Re: do freezing NiCad rejuvenate them or what would you recommend
Post by: MikeK on April 15, 2021, 01:31:33 am
The "memory" effect originated with satellite use, having very specific and regular charging circumstances.  See the wikipedia page on it.  Most people won't experience it.

Anywho...

Why are these NiCads being rejuvenated?  Are they old and at the end of their life?  Or something else?
Title: Re: do freezing NiCad rejuvenate them or what would you recommend
Post by: Circlotron on April 15, 2021, 03:32:04 am
https://batteryuniversity.com/learn/article/how_to_restore_nickel_based_batteries (https://batteryuniversity.com/learn/article/how_to_restore_nickel_based_batteries)
Title: Re: do freezing NiCad rejuvenate them or what would you recommend
Post by: james_s on April 15, 2021, 05:45:29 am
I've managed to squeezer a little more usable life out of tired NiCd batteries but generally speaking it isn't really worth it. At some point they're just worn out and the only thing you can do is replace them.