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[aprssig] flying digipeater?

Scott Miller scott at opentrac.org
Mon Apr 18 23:04:39 UTC 2005

True, but they've got some batteries for high-current pulse applications
that might be suitable...


I think SAFT and others have similar offerings.


----- Original Message ----- 
From: "Robert Bruninga" <bruninga at usna.edu>
To: <aprssig at lists.tapr.org>; <scott at opentrac.org>
Sent: Monday, April 18, 2005 3:55 PM
Subject: Re: [aprssig] flying digipeater?

> >(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

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