[amsat-bb] Re: 20-year Li-Ion Packs
rwmcgwier at gmail.com
Sat Feb 6 19:55:42 PST 2010
Jon Bloom and the ARRL labs did a great job with the BCR. While we are
no longer optimizing the set point for maximum power transfer, the
batteries do appear to have been a very good choice and the BCR and
solar panels are working in those which are still talkative. The South
Atlantic anomaly appears to be the death bringer.
I personally no longer fear batteries as the likely failure mode over
the reasonable lifetime of our satellites when designed by someone who
knows what they are doing. What these lithiums offer us is much great
energy density than we can get with NiCad chemistry. Now it appears the
first shots have been fired in making them last a long time. What we
don't know yet is how structurally sound these new cells with increased
lifetime will be. What will temperature cycling and vacuum do to them, etc.
I hope that this progresses and ends any and all speculation about the
wasted effort (my view alone) on capacitors which do not seem to be
approaching the energy density of bad batteries. The density curves
with caps is looking pretty asymptotic to me. A big leap is needed to
make them competitive.
On 2/5/2010 7:04 PM, Mark L. Hammond wrote:
> Hey, AO-16 and IO-26 still have some decent batteries, even after 20 years or so :)
> Check their orbit numbers (80k-100k), and that's very close to the number of time they have been charged/discharged! hehe
> Neat on the new technology...but our buddies that built those birds picked some good batteries too!
> Mark N8MH
(Co)Author: DttSP, Quiktrak, PowerSDR, GnuRadio
Member: ARRL, AMSAT, AMSAT-DL, TAPR, Packrats,
NJQRP, QRP ARCI, QCWA, FRC.
“Our beds are empty two-thirds of the time. Our
living rooms are empty seven-eighths of the
time. Our office buildings are empty one-half
of the time. It’s time we gave this some
thought.” -- R. Buckminster Fuller
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