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[aprssig] flying digipeater?

Gerry Creager N5JXS gerry.creager at tamu.edu
Tue Apr 19 13:34:37 UTC 2005


Tell that to Cows In Space.  Our first iteration batteries were 
lithium-thionyl chloride cells we obtained from NASA.  We got stellar 
performance (10-15 days) using them with TNC, radio and GPS.  We only 
stopped using them because our source dried up (NASA safety concerns) 
and similar batteries were too expensive commerically.  We went to an 
alkaline technology and changed the batteries every 3 days.

gerry

Robert Bruninga wrote:
>>(non-rechargable) Tadiran 3.6V AA, 2400mAh,
>>The D cells offer (19 amp hours), albeit at $18 each.
> 
> 
> But these cells have very high internal resistance and wont
> even power an HT on transmit.  We are using 112 of
> these D cell lithiums on our ANDE satellite to get a year
> life for our flying digi...  But to get rated life, you cannot 
> draw more than 50 mA per cell..
> 
> We series them four high to get over 12 volts and then
> 28 strings IN PARALLEL. to get life and to also get enough
> transmit current to drive 500 mA 2m transmitter.
> 
> Think of these very high density lithiums as just very-big
> watch batteries.  They have tremendous capacity but
> only if you draw a few milliamps..
> 
> Bob
> WB4APR
> 
> 
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