Herbert Graf wrote:
> On Fri, 2006-05-05 at 18:20 -0700, Bob Axtell wrote:
>   
>> Nate, Dave, I stand in awe!.
>>
>> I have a number of tools driven by NiCAD packs, and a 4-phone system 
>> with 3-cel NiCAD packs in each
>> phone. Not one of these batteries lasted more than a year; the problem 
>> was advanced memory effect. I
>> replaced the phones with NiMH physical replacements; after 2 years they 
>> are still going strong. The tool packs
>> were all the long, round 3.6V packs from B&K (B&E?). They were wiped out 
>> after a year; the newer "GOLD"
>> (NiMH) replacements are still going; has been 3 years for them.
>> I'd really like to know what batteries are being used in space... I'd be 
>> truly amazed if NiCAD was used...
>>     
>
> I don't know about satellites, but a PROPERLY cared for NiCad lasts a
> LONG time.
>
> Both the things you've choosen as "NiCads are bad" examples are HORRIBLE
> to their batteries.
>
> Tools have fast charges that charge the battery in an hour, but charging
> at that rate will quickly destroy a battery.
>
> Cordless phone chargers trickle charge forever, often overheating the
> battery. Even worse they almost NEVER get deep cycled (necessary to
> avoid the memory effect).
>
>   
This may be just my experience. I have designed some commercial products 
with proper chargers
for NiMH and Li-Ion and never had any problems with lifetime.

--Bob


> Back in my school days I regularly used a walkman while traveling
> to/from school. I PROPERLY treated my NiCad batteries (mostly because,
> as a student, I was poor, and $10 for 2 batteries was a HUGE incentive
> to do things right). I regularly deep cycled them. I never left them
> with zero charge. I NEVER overcharged them, and I never used a fast
> charger. Those batteries lasted me well through my final years of high
> school and most of university. I don't have an exact figure in years,
> but I'd say 5 years is probably a good number. The only reason I stopped
> using them was because such high capacity NiMH came on the market and
> the NiCads just couldn't compete.
>
> If I had continued caring for those batteries I'm certain they would
> have lasted me a few years longer.
>
> TTYL
>
>   

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