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[aprssig] flying digipeater?

Robert Bruninga bruninga at usna.edu
Mon Apr 18 22:55:05 UTC 2005


>(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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