[amsat-bb] Ni-Cd's on Satellites and MASS advantage!

[Jim White]

This is a good catch Mike.  I'm saving it to provide to the uni's I work 
with.

Jim

On 3/15/2020 9:47 PM, Mike Wilhelm via AMSAT-BB wrote:
> Stumbled on this paper by accident:
>
> http://adsabs.harvard.edu/full/1998ESASP.416..715C
>
> -Mike
>
> On Sat, Mar 14, 2020, 10:02 PM Jerry Buxton via AMSAT-BB <amsat-bb at amsat.org>
> wrote:
>
>> Amen.
>>
>> Jerry Buxton, NØJY
>>
>> On 3/14/2020 11:53, Robert Bruninga via AMSAT-BB wrote:
>>> We have used NiCds on all of my 4 satellites with no battery problems.
>>>
>>> They are robust, and survive all student mistakes and require no Battery
>>> management system when paired with a matching solar panel design.  IE, as
>>> th batteries approach full charge is the same point where the solar panel
>>> voltage maxes.  Also NiCd's can be safely overcharged at 10% indefinitely
>>> with no concern. (you only get an hour in the sun and then 35 minutes
>>> eclipse)...
>>>
>>> Yes, they are twice as heavy as Lithium, but the advantages FAR outweigh
>>> the criticality of Lithium concerns and complexity of the BMS and total
>>> failure on overcharge or undercharge.
>>>
>>> And MASS is an advantage!   PSAT and BRICSAT-1 are identical 1.5U
>> cubesats
>>> launched at the same time in May 2015.  But PSAT with big C cell NiCd's
>> was
>>> made heavier with lead ballast to 2.3kg.  BRICSAT (1.7 kg) with
>> lightweight
>>> Lithiums has already decayed in November.  PSAT is predicted to last 2
>> more
>>> years!  Same thing for identical RAFT and MARSCOM cubesats back in 2006.
>>> RAFT was ballasted up and lasted TWICE as long as MARSCOM.
>>>
>>> For comm satellites, there is no reason to come in under mass.  Always
>>> ballast up  to the maximum the launcher will allow!
>>>
>>> Bob, WB4APR
>>>
>>>
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> _______________________________________________
> Sent via AMSAT-BB at amsat.org. AMSAT-NA makes this open forum available
> to all interested persons worldwide without requiring membership. Opinions expressed
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> Not an AMSAT-NA member? Join now to support the amateur satellite program!
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