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Nickel cadmium batteries

066logger

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Good evening everyone! Just thought I’d post an interesting thing I ran across today. We were dropping off some leftover metal roof scraps at a local scrapper and he mentioned some batteries he had tried to scrap but nobody would take them. I was curious as I had researched nickel iorn (iorn Edison) batteries before going lifepo4.

These batteries from a distance looked like them and I got excited for a bit. I had to take a closer look and snapped some pics. Nickel Cadmium ? haven’t heard of those before! Came home and did a very small bit of research. Looks like they’re toxic waste ??. Thought it was interesting to find them sitting around decomposing outside… the guy said he had them for several years because no one would take them. They seemed to still have some cells with electrolyte in them.

Anybody got any experience with this battery chemistry? I assume these cells are way too far gone. Do they share any of the same traits as nickel iorn batteries? I could probably have the whole batch if i wanted lol.
 

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"Ni-Cad was the "go to" for rechargeable small devices for many years. Harbor Freight still sells low end drills with Ni-Cad. These are the type that have "memory", if you ever heard of that.

Old paper about early Ni-Cad use. The Skylab had an interesting battery story when they tried to recover some control after it had been left to just drift for a time. Getting the batteries to stay on line and take a charge was a challenge, but they did it.
 
I have some experience with them but not with cells that large.

NiCads are nearly indestructible and are the only battery chemistry that I'm aware of that can actually be rejuvenated and brought back to life.

To fix a NiCad, you drain it to below 0.4 volts, let it rest for a few hours, then drain again to 0.4 volts. You keep repeating this process until it stays below 0.4. I like to wait 48 hours but I think the procedure actually calls for 4 hours or something.

This process breaks up the crystallization inside allowing for more charge surface area and brings the cell back to life.. You can usually get about 90% or more back.

Honestly though, I'm not sure I would want the responsibility of having to recycle them.. While you can drop off small NiCads at any Home Depot, those would have to be taken to a battery recycle center.

The Cadmium is almost as bad as plutonium as far as the environment goes.
 
"Ni-Cad was the "go to" for rechargeable small devices for many years. Harbor Freight still sells low end drills with Ni-Cad. These are the type that have "memory", if you ever heard of that.

Old paper about early Ni-Cad use. The Skylab had an interesting battery story when they tried to recover some control after it had been left to just drift for a time. Getting the batteries to stay on line and take a charge was a challenge, but they did it.
Oh I remember those old ni-cad batteries very well lol. We had a shop guy that loved to leave our drill batteries on the charger overnight. They wouldn’t hold a charge for anything!

I’ll have to read through that paper, thank you! I guess that’s what threw me off about these batteries, I thought of ni-cad as a small sealed drill/rc car battery. These have electrolyte and what appear to be fill caps up top. I assumed for water like a fla or nickel iron battery. I guess I need to research this chemistry better.
 
I have some experience with them but not with cells that large.

NiCads are nearly indestructible and are the only battery chemistry that I'm aware of that can actually be rejuvenated and brought back to life.

To fix a NiCad, you drain it to below 0.4 volts, let it rest for a few hours, then drain again to 0.4 volts. You keep repeating this process until it stays below 0.4. I like to wait 48 hours but I think the procedure actually calls for 4 hours or something.

This process breaks up the crystallization inside allowing for more charge surface area and brings the cell back to life.. You can usually get about 90% or more back.

Honestly though, I'm not sure I would want the responsibility of having to recycle them.. While you can drop off small NiCads at any Home Depot, those would have to be taken to a battery recycle center.

The Cadmium is almost as bad as plutonium as far as the environment goes.
I guess I have experience with ni-cad as well but I just didn’t even realize I was looking at the same beast here. I used to have to deal with ni-cad drill batteries that left a sour taste in my mouth from improper charging.

But those I thought didn’t have liquid in them. These have electrolyte in them of some sort…. And with cadmium being as toxic as it is that seems a bit concerning. Especially with these battery cases having sat in the sun and degraded as they have. I assume a breach and spilling of electrolyte would probably be a small scale Chernobyl? After dealing with fla batteries and seeing how nasty they were corroding everything. I can only imagine the daily change and discharge cycles of a bank like this would probably contaminate the entire area….
 
I guess I have experience with ni-cad as well but I just didn’t even realize I was looking at the same beast here. I used to have to deal with ni-cad drill batteries that left a sour taste in my mouth from improper charging.

But those I thought didn’t have liquid in them. These have electrolyte in them of some sort…. And with cadmium being as toxic as it is that seems a bit concerning. Especially with these battery cases having sat in the sun and degraded as they have. I assume a breach and spilling of electrolyte would probably be a small scale Chernobyl? After dealing with fla batteries and seeing how nasty they were corroding everything. I can only imagine the daily change and discharge cycles of a bank like this would probably contaminate the entire area….
Plutonium is a bit of hyperbole, I was trying to make a point.

Apparently, the cadmium leaches through soils quite easily for some reason.. gets into ground water and can travel.
 
Plutonium is a bit of hyperbole, I was trying to make a point.

Apparently, the cadmium leaches through soils quite easily for some reason.. gets into ground water and can travel.
Oh I totally understand, it may as well be to me though. The static water level in my well is 11’. Too close for comfort to bring anything like that around. And to be honest I was just excited if they were nickel iorn batteries. They interest me just for the long life span and their ability to survive mistreatment. Just for the end of the world scenario where there would be no more batteries available so some power would be better than none. But they’re dang expensive for the amount of power they store…
 
Nickel Iron batteries have the robustness and lifecycle rating advantage.. The problem with them is that they are only about 65 to 70 percent efficient.. If you pump 100kWh of energy into them, you only get back 65 to 70 kWh of energy back.. They also have a high self-discharge rate at some crazy figure like 0.5% every day.. so in a month, they're down 15% just sitting there.

But they do last a long time.

If I was willing to spend the money on the Nickel Iron cells, I'd be more likely to go with an LTO (Lithium Titanate Oxide) cell... Lithium LTO cells can be charged up to 30,000 times... and are stupid safe.
 
NI-CDs are definitely worthwhile if you can get them for next to nothing and if they have life left in them. They are not economical to manufacture for consumer use anymore and some places like EU, possibly US as well ban use in consumer products and EVs because of lack of disposal and recycling options, for environmental reasons. If they are already available and you are giving them a new home, you're probably doing nothing wrong, I would just ensure you mount them on a sealed surface to avoid contamination if they do leak and work on them with the appropriate PPE. From what I hear they don't have as much risk of explosion and fire as lithium. They are still manufactured for emergency back-up and aviation use which does have exceptions in the laws where they are otherwise banned for unsustainability.

I have picked up around 30KWH of brand new emergency lighting NI-CDs from a lighting auction clearance here in Australia. I'm currently examining best charging methods and connecting them. It's a bit more complicated because they can't be paralleled when charging, and in order to fast charge them you can't rely on a particular voltage to determine full charge detection, you need to either use a thermistor on the cells, or a circuit that detects when voltage drops off again when fully charged. You can also trickle charge them over about 16 hours which may work best for solar power. A system may have to be split and switched to have one pack in use and one pack charging at any time. If there is the need to parallel them to provide more current, apparently complete series strings can be top end parralelled, by paralleling an entire series string, instead of paralleling every set in a series string like what is done with lithium ion. This is because they only charge with a voltage a bit higher than the voltage that each string would supply so not much chance of one complete series string draining into another. They do have to be separated from being in parrarel when charging so switching them apart with one relay per string to charge them would work like this. With the size of the cells in the picture, you would probably get away with sufficient size packs with one only in parallel so wouldn't have to worry about this.

I've heard mixed reports about whether or not the memory effect is actually an issue or not, but it was originally discovered in satalites that were being charged from solar power, and then discharge at the same rate with every orbit of the earth, so may be something to take into account with solar power.

From what I've read, they are a good robust battery with a similar lifespan to Lithium Ion, people just remember how much they failed in power tools because manufacturers didn't provide a decent charger and cordless drills etc. often used after a only a few hours of charging because needed straight away, when the simple plug pack trickle charger provided required 16 hours, an overnight charge to charge the battery fully. Things have changed now with Lithium, A BMS and a decent charger is required for safety reasons so manufacturers have been forced to incorporate a decent standard of quality into batteries and charging, so have incorporated accurate charge level displays and other features which have not cost a lot extra than this.

Fast changing of NI-CD batteries only became popular when NI-MH Came along in the 90s, since the overnight trickle charge method with no full charge detection that was widely accepted by Manufacturers using NI-CD cells until then damaged NI-MH cells. Apart from that, both types of cells charge mostly the same using the fast charge voltage drop detection method for full charge.

There are some reports that NI-MH cells might be making a comeback with some manufacturers, NI-MH along with NI-CD have been largely known to be superceded by lithium in recent years, but with current issues with cost and safety of lithium ion, as well as possible improvement in NI-MH cell technology since they were popular, and hopefully an improved cell lifespan over the 500 cycle that they were previously commonly rated at (about half of NI-CD lifespan), some manufacturers are reported to be giving them a second look and considering going back to them in some applications. It is highly unlikely that NI-CD will make a comeback though, with the exception of the limited applications that they currently are still used for because of sustainability and environmental reasons of limited disposal and recycling options and the increased cost of manufacture now.
 
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NI-CDs are definitely worthwhile if you can get them for next to nothing and if they have life left in them. They are not economical to manufacture for consumer use anymore and some places like EU, possibly US as well ban use in consumer products and EVs because of lack of disposal and recycling options, for environmental reasons. If they are already available and you are giving them a new home, you're probably doing nothing wrong, I would just ensure you mount them on a sealed surface to avoid contamination if they do leak and work on them with the appropriate PPE. From what I hear they don't have as much risk of explosion and fire as lithium. They are still manufactured for emergency back-up and aviation use which does have exceptions in the laws where they are otherwise banned for unsustainability.

I have picked up around 30KWH of brand new emergency lighting NI-CDs from a lighting auction clearance here in Australia. I'm currently examining best charging methods and connecting them.
I should probably point out - My experience is with sealed NI-CD, The ones I've bought are strings of 4 - 6 D sized batteries joined together with heat shrink and nickel strips in 4.8 - 7.2 volt packs for emergency lighting. With the large unsealed cells you're looking at in the picture, you would really need to look into the safety side of things with the location you would use them, and disposal when they do come to end of life, which I guess is unknown with the condition of them.
 
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I've just bought 30kWh Nickel Cadmium cells in terrific order. They've been kept charged and maiintained and seem perfectly good for another 20 years. I've just contacted the French/German manufacturers SAFT for a current value and maintenance instructions.
I had some used open/vented/flooded Ni-Cd batteries 60 years ago and they outlasted my interest in electronics in my youth.... They are indeed almost indestructible, which is why they are used extensively in aviation and in spacecraft. The downside is that they are monstrously expensive....
 
Does anyone know where I might find another 5 cells for my battery in Australia? These are wet vented nickel cadmium cells with 625AH. About the size of 2 large car batteries each cell and around 30kg ....
I have 5 spare, but would need 10 to make a 12V system.
 
I have a bunch (about 100 cells or 10 banks of 12 volts) of nicad batteries. I got them for nothing from a railroad company that was upgrading there signaling system. They seem to have big potential but I'm lacking knowledge. I hope someone can help.
They seem to charge fine and will hold a charge of 13 plus volts but don't seem to hold it for very long before dropping to 10 volts. I feel like there might be bad cells in the mix. I understand they can be repaired by discharging.

My first question is: how do I test these cells to see if they are good?
Also, how would I charge or discharge individual cells (1.2 volts each)? The smallest charges I can find is 6 volt.

Any help is appreciated.
 

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Can't help with charging single cells but replacing the electrolyte brought mine back to life. I had a hard time finding potassium hydroxide 25 years ago when I had those cells.
 
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