> From: Moose <olymoose@xxxxxxxxx>
>
> On 12/15/2010 11:00 AM, Jan Steinman wrote:
>> Although it's open on my desktop, I've not looked at the
>> BatteryUniversity.com site yet, but my understanding of classic NiCd is that
>> repeated incomplete discharging to about the same level causes a crystalline
>> precipitate to form at a certain location related to the discharge depth,
>> therefore causing the mis-named "memory effect." (It should really be called
>> the "forget effect." :-)
>>
>> Memory effect is not a problem when the cell is repeatedly discharged to
>> different levels. Classic case: a cop runs a walkie-talkie for eight hours a
>> day and drops it in the charger overnight -- bad news for NiCd cell life.
>> But memory effect is not likely if you're using a flash or motor drive for
>> various periods of time and then topping off on a charger.
>
> "Among rechargeable batteries, nickel-cadmium remains a popular choice for
> two-way radios, "
>
> Since what you say here doesn't agree with what's on that site, perhaps you
> might read it and resolve the differences.
Yea, I'll have to check that out, because it doesn't go along with my
experience as a ham-radio operator, my work as a repair tech in a two-way
communications shop, nor my stint as an RF engineer.
I don't know of any hams who still use NiCd cells in their two-way radios, but
note that the OEM battery packs you get from Icom for older radios still have
them. Perhaps its just because NiCd's are still cheaper. (New hand-held ham
gear is almost all lithium powered.)
NiCds do have lower internal resistance than NiMH, which might make them
preferable in high-current applications -- like photo strobes. But that
wouldn't explain hand-held radios, which have relatively moderate current
needs. And if they're so good for hand-helds, why don't you ever see them in
cell phones? Puzzle.
But such fun has to wait. I have to go pick up a buck to romance our four
Nubian goats today.
Obligatory camera content: I need to take some photos of our zero-mile raw goat
milk ice cream... if there's any left...
----------------
Religions are the great fairy tales of conscience. -- George Santayana
:::: Jan Steinman, EcoReality Co-op ::::
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