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NiCd Battery question

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I know batteries are rated by amp-hour or milliamp-hour. Is the rating perfectly linear or is there a fudge factor? In other words, with a 2000 mAhr battery is the usage 10 hours at 200mA as well as 2 hours at 1000mA. Or will the usage realized be closer to something like 10 hours at 200mA as well as 1.25 hours at 1000mA?
 
You really have to consult manuafacturer's data for the said battery. Here https://www.electro-tech-online.com/custompdfs/2011/06/Nicad_vs_LeadAcidBatteries_TechBulletin.pdf is just a brief discussion of lead acid and Nicad and doesn't quite address what your asking.

Temperature and self-discharge play a part too. I know the AHr rating is dome at a specific rate or discharge, but I don't know what that is and it allows comparisons. At either extremes there will be issues. At high rates, temperature may increase and decrease available capacity. At extremely low rates, storage time may prevail. The internal condition of the battery will be an issue too. Charging rates are often based on capacity.

CCA or cold cranking amps is a metric used for lead acid automotive batteries.
 
Generally the higher the discharge rate, the lower the amp-hr value you will measure. I believe the posted rating is typically for a 10Hr discharge rate (1/10 the Ah rating)
 
Ni-Cad batteries are obsolete and are very poisonous. They have been replaced by Ni-MH cells for many years and the Ni-MH cells have a much higher Ah rate and no "memory" problem.

Energizer have a Ni-MH battery tutorial and datasheets on their website that show almost the same Ah rating at a high current and at a low current.
 
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audioguru, NiCad's are NOT obsolete by any stretch of the imagination, let alone yours even though you KEEP saying this every time the topic of NiCad's come up. NiMH's are more commonly used and in general should be used unless Lithium cells are practical, NiCad's still have niche markets and cost benefits which makes them still practical.

The toxicity of the Cadmium is irrelevant as ALL batteries must be disposed of according to local laws, and must never be thrown in the trash. While Cadmium itself is considered toxic (poisonous) The bulk of the environmental consequences come from all the other active chemistry that goes along with it, and most Cadmium poisoning occurs from mining contamination. NiMh's still contain a huge amount of active compounds and Lithium's aren't any better. Cadmium is picked on because it is a toxic metal IN ITS IONIC STATE, as a solid metal it's as harmless as any other.

Not sure why you don't pick on Lithium more as it's a psychoactive compound, with pretty serious effects.

No battery will exhibit a linear capacity with different discharge rates unless they are very close. It's physically impossible; with increased current comes increased ohmic losses in the cell itself as heat which degrades the battery chemistry over time. NiMh's have come a long way, but will never overcome these INHERENT issues with all battery chemistry.
 
Ni-MH cells are sold in grocery and department stores. Cheap Chinese solar garden lights come with a Ni-Cad cell that retails for about $1.00.
AA size Ni-MH cells have a stainless steel case and a capacity of 2300mAh. The Ni-Cad cells have a steel case that rusts away outdoors and a capacity of only 400mAh to 600mAh.
Model racing cars use Ni-Cad cells for the weight on the wheels.

My electric RC airplanes use lightweight and powerful rechargeable Li-Po cells. This evening the connector on one broke, the wires shorted together and the battery began smoking. I burnt my fingers separating the wires but now the insulation on them is burnt away and the battery is destroyed.
 
AG lithium batteries for airplanes have nothing to do with NiCd's being obsolete or even useless, the energy density of a NiCd is so low that the only worse chemistry for a battery I can think for an RC plane is lead acid batteries. I don't however hear you complaining about the toxicity of lead acid batteries on the forums, you do however seem hell bent on spreading misinformation about NiCd chemistry.

And it's not so much the weight for RC cars that's the advantage, it's the control of the center of balance. The main body of the car tends to still be made out of high strength light weight composites, the cars weight is brought up with the batteries but the real advantage is that the extra weight of a flat pack NiCd pack for an RC car moves the center of gravity so low in the car that it dramatically increases handling, otherwise you'd just use lithium batteries and lead weights. The peak power put to the ground on an RC car is vastly larger than for an RC aircraft so the NiCd chemistry as well along with the weight makes it the ideal solution, even the best of the best of the BEST Lithium packs can't hold a shadow to the short circuit current of the same capacity NiCd. The only use I could think of Lithiums for in RC cars would be for endurance races... which is really a boring sport from an RC perspective.

And the chinese solar lights again? Really what does that have to do with anything? The Chinese still make products with lead based paints for children's goods, you can't blame stupidly poor application for a flaw in the inherent usefulness of the chemistry itself.

AG, the proof is in the pudding so to speak. Even within the European Union (2006/66/EC) so called ban on NiCd batteries there are exceptions, like medical uses, alarm systems, emergency lighting and power tools. So again your statement of NiCd's as being obsolete is completely out of place. They're still used in those types of devices because for their particular needs NiCd's fill the roll required.

Hopefully this doesn't derail ADW's question too much but I feel someone has to set the record straight about audioguru's statements which differ so very much from reality. This is not the first time he's posted in this manner as well on this topic.

For actual information purposes I would like to reference this thread. As I described how to go about testing individual cells for pack matching and determining the condition of pretty much any cell. As Kiss said you really need to consult the graphs provide from the maker of the battery, however in many cases such information is not available so empirical testing (as described in the thread) is the only way.

https://www.electro-tech-online.com/threads/nicad-battery-testing.116620/
 
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Funny that you link back to that thread. I am putting the finishing touches on the tester now and in doing so, was pondering some of the design features.
 
Please link details.
 
AG ...... your statement of NiCd's as being obsolete is completely out of place. They're still used in those types of devices because for their particular needs NiCd's fill the roll required.
I used Ni-Cad cells in my radios and cassette players in the '70s.
They were Energizer (previously called Eveready) and Dynacharge (made by Duracell). In the '90s I began using Ni-MH cells.
Today Energizer marks all their Ni-Cad datasheets with OBSOLETE so they agree with me.

I walk my dogs on a boardwalk beside Lake Ontario. There is a marina where many private boats go. One guy is always sitting there dressed like a sailer and playing a portable 45 RPM record player that sounds awful. For 45 years I have said that the 45 RPM record player is obsolete. But since one is still being used today, you say it is not obsolete.
 
Obsolete is relative. NiCads have their nitche. They also have their draw backs, ie. the memory effect. Unfortunately, my chargers won't charge rebuilt packs made with NiMH batteries (either home made or professionally), so the majority of this discussion is pointless. I can't buy new equipment and what I have works great (better than the old guys record player).

Unless you're using Li-Ion (and a few select others which I can't recall off the top of my head). They are ALL hazardous waste with the expection of the Li-Ion. Li-Ion has the advantage of breaking down into salts when exposed to water.
 
Not considered hazardous but still considered highly reactive.
https://yosemite.epa.gov/OSW/rcra.nsf/Documents/CC7D81DF307086C085256611005AC8EC


These problems are going to grow as Lithium batteries take over more and more of the market and have a chance to build up in waste streams.

Also AG Energizer doesn't make many NiCd's anymore and I'm not sure what PDF you're referring to but if anything was obsoleted it was that specific NiCd chemistry. New anode/cathode materials membranes and variations on electrolyte chemistry have been developed, just not be Energizer. Sanyo has something like 4-5 different specialized NiCd cells currently in production.
 
Energizer has most of their Ni-MH cells made for them in Japan, maybe by Sanyo. Their Ni-MH 9V battery is made for them in Germany.
They mass produce their own alkaline cells in USA. I don't know about their tiny cells for watches and hearing aides.

They haven't sold a Ni-Cad cell for about 14 years when their much better Ni-MH cells were introduced and obsoleted the old Ni-Cad cells.
 

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ag, please refer to the following links.

https://www.electro-tech-online.com/custompdfs/2011/06/nickelcadmium_appman.pdf
That's the last reference to an Energizer product that I can find that includes information about NiCd's, and it's 10 years old.

They might not produce them anymore, probably never did as you said Sanyo produces their NiMh line, Sanyo still produces NiCd's, Energizer just stopped selling branded NiCad's publicly.. Oh wait....

**broken link removed**
That's current..

Before posting again I would strongly recommend doing some research on the subject.
 
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The Energizer cordless phone battery using only 3 obsolete low capacity Ni-Cad AA cells is a ripoff.
4 Ni-MH AA cells with a capacity of 2300mAh (over 3 times better than those old Ni-Cads) cost much less.
 
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