Re: [amsat-bb] PCSAT2 high-beta-angle shut-down

["Robert Bruninga" <bruninga@xxxxxxxx>]

>If your PCSAT2 LiIon battery is the same as used 
>for scale-models, they you have to assume Cell 3 
>(1.52V) as dead. These type of batteries are very  
>sensitive to being discharged below 3V. 

Yes, we have observed cell imbalance since our
charging is very simple system.  These are first-time
in space for these types of cells.  But they are 
very big 55 Amp Hours (about 100 times bigger
than we needed), because NASA required us to
survive 5 full days in constant shadow AND
with heaters ON to keep from going below -60C.

It has been a luxury not to worry about battery
capacity.  But now we are in an ISS attitude that
has the sun hitting our solar arrays at an angle 
of about 15 deg and this is not enough current 
to maintain us.  So PCSAT2 shut down on 
under voltage.  We should get her back when sun
angles improve again.

thanks
Bob
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