On Thu, 26 Oct 2006 09:37:27 GMT, ml wrote:

question is what is that value how do i calculate how big a battery i
need at the know constants?

Hi Myles,

It is a matter of three things:
1. Amp-Hour or Watt-Hour capacity;
2. Demand for Amps or Watts;
3. Duty ratio.

Based on your specification for a 5W rig (I assume it is a hand held,
a small mobile would be more like 20-35W) and an efficiency during
transmit of 50-70%, then your demand would be at least 10W during
transmit. Receive would require some baseline power, my guess would
be 2W, maybe less. If you listen more than you talk by a factor of 5,
then you could count on an average demand of 2W.

Divide this 2W into the Watt-Hour capacity (I will assume 100WH) and
your power source should last two days continuous use (do you plan on
sleeping?) or 50 hours of on time over any more extended period. That
is, if you sleep 12 hours, you can stretch the service time out to 4
days. If you operate only 2 hours a day, you can stretch the service
time out over a month an a half.

73's
Richard Clark, KB7QHC

Richard Clark wrote:
On Thu, 26 Oct 2006 08:53:31 -0700, Jim Kelley
wrote:

Richard Clark wrote:


Hi Myles,

Fuel Cell??? That is a pretty pricey option.

More than likely it is 100WH (Watt-hour, not Watt) rated.

https://jadoopower.com/fuel_cell.html


Which reports:
Output: 12 VDC Nominal
Wattage: 100 W Continuous

So apparently your correspondent was correct after all.

WOW! Infinite Watt Hours. I think we can walk away from the mid-east
right now.

No, actually when you take time to understand the literature (like
Myles evidently has), it becomes quite clear that the limit to the
rate at which energy can be extracted from the power unit is 100
watts, and that the total amount of energy which can be extracted is
determined by the capacity of the fuel cannister; either 130
watt-hours or 360 watt-hours.

So it seems that if you want to be able to rely on this power source
for any extended length of time, 5 watts would not be an unreasonable
load. I'll wager it would even count for 100 extra points at Field
Day - albeit at a cost of $15-$20 a point.

73, Jim AC6XG

Always wanted a 1 FARAD (or bigger) capacitor!
Where can you buy one?? (Short of buying a
"Charged "one, I.E. Storage Battery)? Oh
well only 6 Months to April First!
Jim NN7K


Richard Clark wrote:



Not unless you can assemble a couple hundred Farads (note the complete
absence of pico, nano, or micro in that Farads). The short version is
DON'T GO THERE.

73's
Richard Clark, KB7QHC

Jim - NN7K wrote in QE90h.22140$e66.18599
@newssvr13.news.prodigy.com:

Always wanted a 1 FARAD (or bigger) capacitor!
Where can you buy one??

Try your local car stereo place. About the size of a tennis ball can.
Best Buy has some on their website. Search for capacitor.

--
David
KR7DH

Jim - NN7K wrote:
Always wanted a 1 FARAD (or bigger) capacitor!
Where can you buy one?? (Short of buying a
"Charged "one, I.E. Storage Battery)? Oh
well only 6 Months to April First!
Jim NN7K


http://www.radioshack.com/search/ind...ad%20capacitor


73, Jim AC6XG

On Thu, 26 Oct 2006 21:20:48 GMT, Jim - NN7K wrote:

Always wanted a 1 FARAD (or bigger) capacitor!
Where can you buy one?? (Short of buying a
"Charged "one, I.E. Storage Battery)? Oh
well only 6 Months to April First!

Hi Jim,

1 FARAD (or bigger) capacitors have been around for YEARS. Go to any
Hi-Fi shop and spend as much as you want. Be warned that cost is
proportional to breakdown voltage rating.

Or try:
http://www.hobbyengineering.com/Sect...tml#CatPSSUPER

73's
Richard Clark, KB7QHC

Jim - NN7K wrote:
Always wanted a 1 FARAD (or bigger) capacitor!
Where can you buy one?? (Short of buying a
"Charged "one, I.E. Storage Battery)? Oh
well only 6 Months to April First!
Jim NN7K


Richard Clark wrote:



Not unless you can assemble a couple hundred Farads (note the complete
absence of pico, nano, or micro in that Farads). The short version is
DON'T GO THERE.

73's
Richard Clark, KB7QHC

Why settle for a measly 1 F when you can have 50 F?

Go to www.digikey.com and search for 283-2511-ND.

--
Jim Pennino

Remove .spam.sux to reply.

On Thu, 26 Oct 2006 15:02:55 -0700, Richard Clark
wrote:

Or try:
http://www.hobbyengineering.com/Sect...tml#CatPSSUPER

Or for up to 50F for less than 50 Cents a Farad:

http://www.newark.com/NewarkWebComme...comSearch=true

Interesting to note this one of the few, practical (meaning making
money in a commercial market) Nanotech applications of an aerogel.

73's
Richard Clark, KB7QHC

In article ,
Tom Ring wrote:

ml wrote:


question is what is that value how do i calculate how big a battery i
need at the know constants?



Rich the reason i thought of cap's was both the short key down time and
the article in cq of this new powersupply that uses a few 5farads it
got me thinking if it could be modified to do dc to dc regulation
rather than 120v ....maybe i was pushing it, then i thought of
supercapacitors i dunno

I got the pricing from jadoo's site for the unit plus 6 container combo.
And you will still need something to refill.

On the battery, when we used to VHF contest with a light (600W)
generator and power supplies, we would put a 25AH battery across each 15
amp supply and we could draw 40 or 50 amps on CW/SSB peaks with no
issues. So you would probably be well served by one of the 7AH UPS
batteries from a place such as Batteries Plus. They cost about $25 and
are about 7"Lx2"Wx4"H.

tom
K0TAR

gosh, i sure do appreciate everybody's help, sincerely, but alas, i
still have no concise way to calculate what size battery or cap i need

but i can add a few things, even thou it's sorta a different topic
many here seem concerned about the size of the canisters and refilling
them, this is not a concern as the unit will be feed directly off a
large Hydrogen tank, not the little canisters i do not need to
calculate how long the unit(jado) will run at load vs fuel supply this
is already a known constant and published thats the easy part

the unit does 12v unregulated at about 7amps if you hit 7amps for long
voltage goes down to 10v so i will add some regulator if needed

when i said my radio(2m mobile) will be ""putting out 5w on low pwr""
i ment 5w rf output not current draw sorry

so rich since your calculation was for ah what would it be for for
the correct above spec's?? amps or 100w (no ah)?

i would have to have a battery big enough to be -drained little enough
so that the jado would be able to recharge it during the rx time(least
load) from what tx drained the battery obv if the battery is too
big then the jado wouldn't be able to recharge it or float it

right now i have 2 G27(parallel) and i float them at less than 1amp

naturally when i say recharge i don't mean from anything other than a
slight drain as in normal tx /rx

so the question become how do i calculate that? and would a ultra cap
fit in ?

i thought it would be kinda simple, gut wise i can guess but what i
was hoping for here was a more precise calculation of what would do
the trick

again thanks all for taking the time to respond , i always learn
something


ml

Jim - NN7K wrote:

Always wanted a 1 FARAD (or bigger) capacitor!
Where can you buy one?? (Short of buying a
"Charged "one, I.E. Storage Battery)? Oh
well only 6 Months to April First!
Jim NN7K


Check with your local high power car audio shop. They carry them.

I have one, but it's only half a farad at 30 volts.

tom
K0TAR