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Re: NiCd Battery PCsat



Bob:

 >>The real issue is what
 >> is the  temperature of the battery in PCsat please?

 >Per orbit, they cycle maybe 5 degrees from about 3 to 8 deg C now. With
 >the LOWER temp being when they will see the deep cycle... (that sounds
 >like thats good news)...

Yes, my suggestion to you is think only of 3 C, focus on 3 C at this time.

 >> [cold for a NiCd in my terms is 5c and below, hot is above 25c.

 >Wow, sounds like we nailed it!

Well were not getting rushed with offers of insurance policies yet, but it 
is a lot better than 25C would be......

 >> You alone have to cut this one, I offer that keeping
 >> things cold and minimizing the range of voltage swings are the things to
 >> focus on.

 >Yep, I had that suspicion as well.  Since it goes against the
 >first order conventional wisdom, that is why I wanted a second opinion

The risk remains however we are dealing with unknown variability of each 
cell in the battery, but I agree it seems there is some improvement.

 >Yep, thank goodness it is only a binary decision, since weighing even a
 >few more control options (if such were available) maes for LOTS and LOTS
 >of more possibilities and all with imprefect infomration.... <grin>

We would of course have more options if we had more information......

A further question of academic interest to me please, what cells are you 
using please in the battery?  I don't know what is going on in this field 
at this time so if you can give me any on line reference or a specification 
reference it would be appreciated.

 >THANKS!  Perfec answers!

Well lets hope for positive results, that will be a good sign of some level 
of success.  Please focus on 3C, that as I see it is your hook to the best 
success you can have under these circumstances.

Please keep me in the loop as you make progress here.  I am getting older 
now, and things don't come back as fast as I might like after nearly 30 
years since I started on this journey of trying to understand NiCd 
cells.  I had 5 years to watch the battery in OSCAR VI die, I almost had an 
obsession with trying to understand why single NiCd cells almost always 
worked great, but when you put two of them in series things started going 
wrong more quickly than they would if the cells were kept separate.  If I 
keep this up front for a while I may well remember other things that might 
prove useful.  In the interim the wood pile here on this small island home 
is not getting any larger while I am in here banging away at this keyboard 
- back to work I go, and it has just moved above 3C here in the last hour 
hi.......

73

Larry
VA3LK

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