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Re: super capacitors



>  But, it would seem to me that the best use of a Super cap 
> would be for power situations like we have on PCSat-1, 
> where there is enough power on average, but not enough for 
> the peak draw.  

Yes, that is exactly the application.  And that is why PCSAT or
any other packet Satellite can have a 10 dB stronger downlink
than any other FM satelillte, because the transmitter is only
on for 1 second at a time and the average TX power even under
full load of users is less than 10% of peak power.

But I am very leary of these super caps in space....

1) New technology, (not space proven for 10 years)
2) Based on chemical deposition (think electrolytics?)
3) Extremely small barriers between the plates
4) tremendous energy storage, and also then
    tremendous energy burnthrough in case of something
    getting "between" the "plates"
5) Radiation damage putting a hole in the "plates" causing
    tiny, then massive current short.

But then, I know NOTHING of these capacitors, but to get
1000 Farads, think ACRES of surface area and remember that
the slightest imperfection or radiation hit, will cause an avalanche
destruction.   A hit on a silicon chip is one thing, each gate is only
a few microns across.  And we KNOW that a hit will occur.

But multiply that square footage cross section by several billion
to make a capacitor and it just seems to me that there is a lot
more that can go wrong in space.

Again, I know nothing about these super caps.  But the
concerns above come to mind...

Remember, if these new capacitors are not space proven and
guaranteed to last 10 years or more, then it is not even worth
doing, since Nicads at 10% depth of discharge can easily
last that long.

Again, purely an opinion.  Just thinking out loud.

Bob, WB4APR
----
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