[amsat-bb] Re: 20-year Li-Ion Packs
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. Bob N4HY 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! 73, 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 Active: Facebook,Twitter,LinkedIn ___ Sent via amsat...@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: 20-year Li-Ion Packs
... Hey, dude, '16 and '26 have some booty-kickin' batteries in 'em ... I meant no slight to any person nor project. Just thought this would be a positive (pun intended) post to go into the weekend ... (grin) Clint, K6LCS NOTE: Opinons expressed are those of Clint's only - as if anyone else thinks like him, anyway. ___ Sent via amsat...@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: 20-year Li-Ion Packs
Yes, I concur! At 04:13 PM 2/5/2010 -0800, Clint Bradford wrote: ... Hey, dude, '16 and '26 have some booty-kickin' batteries in 'em ... I meant no slight to any person nor project. Just thought this would be a positive (pun intended) post to go into the weekend ... (grin) Clint, K6LCS NOTE: Opinons expressed are those of Clint's only - as if anyone else thinks like him, anyway. Mark L. Hammond [N8MH] ___ Sent via amsat...@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: 20-year Li-Ion Packs
On Friday 05 February 2010 18:31:08 Clint Bradford wrote: Japanese research and development firm Eamex claims to have found a new way to increase the typical average life of a high-capacity lithium-ion battery. Eamex's new technology will allow the demanding batteries to sustain over 10,000 recharges over the course of 20 years. http://tinyurl.com/20yrbatt I remember just a few years ago how thrilled we consumers were with 1200-1400mAH in NiMH AA cells. Now we have twice that capacity ... It's very exciting seeing both consumer and commercial-grade battery technology mature. Clint, K6LCS Thank you for posting this Clint -- I'd heard of this from a friend but he could not give me the link, but now I have it. I am happy to hear of this, but I take it with some skepticism, in that this is a projected life time, not a real one. While I would *love* for this to be true, I wonder what un-thought of chemical reactions there might be, affecting the battery some years down the road. To give an example that fuels my skeptic tank, consider recent disk drives and the enormous published mean time between failures for them. They were garbage, and looking at WD disks (scorpio blue), they don't publish MTBF any more. So while I want aa batteries with 13.1AH capacity and 12,000 recharge cycles, I'm going to have to wait for them... ;-) --STeve Andre' wb8wsf en82 ___ Sent via amsat...@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
