Need assistance selecting a battery
Need assistance selecting a battery
(OP)
Hi,
I need a battery that can provide 11.3W at 12VDC for less than a second, and it only needs to be used once. It will be used on a sattelite, so it needs to be able to survive the trip. Also size and mass area a huge factor, we are working on only a 4"x8" board and it is nearly full.
Any suggestions? I was thinking watch battery, but I doubt I can get the power I need from it.
I need a battery that can provide 11.3W at 12VDC for less than a second, and it only needs to be used once. It will be used on a sattelite, so it needs to be able to survive the trip. Also size and mass area a huge factor, we are working on only a 4"x8" board and it is nearly full.
Any suggestions? I was thinking watch battery, but I doubt I can get the power I need from it.






RE: Need assistance selecting a battery
Sounds like a detenator to me.
RE: Need assistance selecting a battery
Could you supply a little more information, what will the 11.3W at 12V trigger?, what is the birds power bus system rated for?, what are the specs., and standards you are required to meet?, what power system did the project systems engineer, approve for your assembly.
RE: Need assistance selecting a battery
Theoretically speaking,
E = 0.5CV^2
C = (2 * 11.3W * 1s / 12V^2 ) = 0.16F
RE: Need assistance selecting a battery
Aleham's value needs to be increased by about a factor of 3 for a 2V droop. However, you'd need a capacitor with very low ESR, otherwise, you'll need a higher voltage to accommodate the series resistance. A single AAA has a short circuit current in excess of 1 A, so a charging circuit built around a AAA cell would charge up in a relatively short time, but you'll need a minimum of 15x boost.
TTFN
RE: Need assistance selecting a battery
RE: Need assistance selecting a battery
Thanks for the ultracapacitor idea, we thought capacitor but I guess whoever looked into it, didn't find anything.
RE: Need assistance selecting a battery
Is this for an explosive fastener?
RE: Need assistance selecting a battery
The super capacitor looks really promising. Does anybody know if they are space rated? And how can I tell if they are capable of putting out the current I need?
Also, an update, I was informed at todays meeting the requirements are now known exactly. They are 1A at 28VDC for 15 seconds. (By my calculations I'll need just over a farad).
RE: Need assistance selecting a battery
http://www.tiniaerospace.com/fbfc2-16-31sr2.html
Based on that, you'd need to maintain 28V continuously for the time required.
TTFN
RE: Need assistance selecting a battery
http:
http://www.avxcorp.com/docs/catalogs/bestcap.pdf
The higher voltage ones are significantly lower capacitance:
http://www.evanscap.com/THQA2-FSpec.PDF
Although, there's this one:
http://www.tavrima.com/pub01a.html, oops, it weighs 35 kg!!
TTFN