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fuel cell battery buffer or cap?
hi
was wondering if someone had some thoughts on this and might be able to help me 'calculate' the value i need I was thinking of getting a jado fuel cell, it puts out 100w (about 8amps ?) @12vdc it's not totally regulated, at full output the volts dip a bit wanted to power a 2m rig at low power 5w out it falls w/in the spec's of the jado but i wanted a buffer at first i thought of a battery using the full cell to charge the battery during receive since tx is brief but how do i calculate how big a battery i need? i also wondering if perhaps a capacitor or a few of them might also do the trick and if so how to size them not sure the pro's /cons' of battery vs cap's naturally if i used the caps' i'd prob get a dc to dc regulator any help appreciated |
fuel cell battery buffer or cap?
On Thu, 26 Oct 2006 00:22:01 GMT, ml wrote:
I was thinking of getting a jado fuel cell, it puts out 100w (about 8amps ?) @12vdc Hi Myles, Fuel Cell??? That is a pretty pricey option. More than likely it is 100WH (Watt-hour, not Watt) rated. wanted to power a 2m rig at low power 5w out it falls w/in the spec's of the jado but i wanted a buffer Well, a 5W transmitter is not going to load it too heavily, but you have to figure that 5W out is a 10W demand on the battery. This means your battery will work 8 - 10 Hours continuous (you don't sit on the key, do you?). at first i thought of a battery using the full cell to charge the battery during receive since tx is brief but how do i calculate A battery - fuel cell - battery? how big a battery i need? At least 100WH, undoubtedly more. Why charge a fuel cell with a battery? Why not cut out the middle man and just run battery operation? i also wondering if perhaps a capacitor or a few of them might also do the trick and if so how to size them 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 |
fuel cell battery buffer or cap?
ml wrote:
hi was wondering if someone had some thoughts on this and might be able to help me 'calculate' the value i need I was thinking of getting a jado fuel cell, it puts out 100w (about 8amps ?) @12vdc it's not totally regulated, at full output the volts dip a bit wanted to power a 2m rig at low power 5w out it falls w/in the spec's of the jado but i wanted a buffer at first i thought of a battery using the full cell to charge the battery during receive since tx is brief but how do i calculate how big a battery i need? i also wondering if perhaps a capacitor or a few of them might also do the trick and if so how to size them not sure the pro's /cons' of battery vs cap's naturally if i used the caps' i'd prob get a dc to dc regulator any help appreciated I would use a small gel cell across the 12V output. I do have some worries since it says "nominal" 12V output and no better information than that seems to be available on the site. Except the prices. You must be quite well off to consider purchasing this, since the XRT is $7999 and does not include a refill station at $599 or $1799, so once your canisters are empty you are done. If you can afford this system, I would suggest you buy a nice top end deep cycle battery, $300 for 80 AH is in the correct range. Or you could just burn gasoline in a 2000W Honda which costs about $1000, makes almost no noise, is quite light, and will generate less CO2 than the fuel cell system will when you get down to reality since the fuel cell system is actually powered by the fairly inefficient electrical grid. And it will cost a ton less as well as delivering 20 times the peak power with commonly available fuel. tom K0TAR |
fuel cell battery buffer or cap?
Tom Ring wrote:
If you can afford this system, I would suggest you buy a nice top end deep cycle battery, $300 for 80 AH is in the correct range. My 115 amp hour deep cycle trolling battery only cost about $70 at Sam's Club. -- 73, Cecil http://www.w5dxp.com |
fuel cell battery buffer or cap?
Tom Ring wrote:
Or you could just burn gasoline in a 2000W Honda which costs about $1000, makes almost no noise, is quite light, and will generate less CO2 than the fuel cell system will when you get down to reality since the fuel cell system is actually powered by the fairly inefficient electrical grid. And it will cost a ton less as well as delivering 20 times the peak power with commonly available fuel. BTW, the 1000W EU1000i model will deliver 1000W at 3.8 gallons per day, and 250W at 1.7 gallons per day. The unit is listed at 790 USD. There are simple modifications to use a boat gas tank (usually about 6 gallons) with this unit which would make the run time 3 days for most emergency amateur use before refill. I would take this as a first responder system in a heartbeat. I also wonder where one would get the energy to refill the hydrogen for the fuel cell unit when in a place like New Orleans after Katrina. Gasoline would still need to be hauled in, and would probably be more efficiently used providing power directly from a smart generator than splitting water to make hydrogen which would then be used in a fuel cell. tom K0TAR |
fuel cell battery buffer or cap?
ml wrote:
hi was wondering if someone had some thoughts on this and might be able to help me 'calculate' the value i need I was thinking of getting a jado fuel cell, it puts out 100w (about 8amps ?) @12vdc it's not totally regulated, at full output the volts dip a bit wanted to power a 2m rig at low power 5w out it falls w/in the spec's of the jado but i wanted a buffer at first i thought of a battery using the full cell to charge the battery during receive since tx is brief but how do i calculate how big a battery i need? i also wondering if perhaps a capacitor or a few of them might also do the trick and if so how to size them not sure the pro's /cons' of battery vs cap's naturally if i used the caps' i'd prob get a dc to dc regulator any help appreciated If all you really need is 5W out I would spend my money on about 5 amps of solar cells at 12 volts nominal, a really good charge controller such as this one - http://store.solar-electric.com/sbchco2512vm.html - and a good 200 or 300 AH deep cycle, you would be well ahead of the fuel cell solution. And it would keep you in energy for a lot of dim days. tom K0TAR |
Gang fuel cell battery buffer or cap?
In article ,
Richard Clark wrote: On Thu, 26 Oct 2006 00:22:01 GMT, ml wrote: I was thinking of getting a jado fuel cell, it puts out 100w (about 8amps ?) @12vdc Hi Myles, Fuel Cell??? That is a pretty pricey option. More than likely it is 100WH (Watt-hour, not Watt) rated. wanted to power a 2m rig at low power 5w out it falls w/in the spec's of the jado but i wanted a buffer Well, a 5W transmitter is not going to load it too heavily, but you have to figure that 5W out is a 10W demand on the battery. This means your battery will work 8 - 10 Hours continuous (you don't sit on the key, do you?). at first i thought of a battery using the full cell to charge the battery during receive since tx is brief but how do i calculate A battery - fuel cell - battery? how big a battery i need? At least 100WH, undoubtedly more. Why charge a fuel cell with a battery? Why not cut out the middle man and just run battery operation? i also wondering if perhaps a capacitor or a few of them might also do the trick and if so how to size them 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 thanks to all that replyed\ Tom , you changed my equation, combustion generators and solar are not options or the question, it was a rather obvious choice but thanks not sure where everyone got their spec's from and pricing but your numbers are off and most likely i'd get a sample unit free , tom i also wouldn't be using it's charging canisters but sstraight into the tank the jado i mentioned list price is around 2k$$ and i can get it for less list and it is 100w it lit my 75w light bulb pretty steady and bright Question: i thought since my key down isn't steady that might be enough juice to then charge top off'' the battery but i didn't know how to size it i'd have x amps (or ah) from fuel cell x ammount of draw think my rig pulls 5amps? tx, x ammount capacity from batt,, so after say a min of key down the battery would be y drained, given a big enough battery Y (drain)would need to be small enough such that the 12/8amps out of the Jado fuel cell would be able /fast enough to top it back off 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 |
Gang fuel cell battery buffer or cap?
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 |
fuel cell battery buffer or cap?
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 |
fuel cell battery buffer or cap?
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 WOW! Infinite Watt Hours. I think we can walk away from the mid-east right now. |
Gang fuel cell battery buffer or cap?
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 |
fuel cell battery buffer or cap?
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 |
Gang fuel cell battery buffer or cap?
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 |
Gang fuel cell battery buffer or cap?
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 |
Gang fuel cell battery buffer or cap?
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 |
Gang fuel cell battery buffer or cap?
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 |
Gang fuel cell battery buffer or cap?
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. |
Gang fuel cell battery buffer or cap?
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 |
calculations/ fuel cell battery buffer or cap?
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 |
Gang fuel cell battery buffer or cap?
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 |
calculations/ fuel cell battery buffer or cap?
ml wrote:
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 Please pardon the dumb question, but if you have a 100 watt fuel cell why do you need a battery? 73, Jim AC6XG |
calculations/ fuel cell battery buffer or cap?
ml wrote:
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 I thought my statement was clear, but I will repeat it - "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." Float that across your fuel cell and you will be fine. Of course, if the fuel cell doesn't put out at least 13.5 vclts with your rig on receive, a "12 volt" float battery won't have enough charge in it to speak of. Then it would be back to capacitors and the interesting problem that they would bring along. Such as a 0 volt charge current that could possibly be damaging to your fuel cell. This whole thing seems a very expensive way to have not very good portable power. You have never stated why you must have a fuel cell. Would you care to enlighten us? tom K0TAR |
ans calculations/ fuel cell battery buffer or cap?
I thought my statement was clear, but I will repeat it - "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." Float that across your fuel cell and you will be fine. Of course, if the fuel cell doesn't put out at least 13.5 vclts with your rig on receive, a "12 volt" float battery won't have enough charge in it to speak of. Then it would be back to capacitors and the interesting problem that they would bring along. Such as a 0 volt charge current that could possibly be damaging to your fuel cell. OK, that was clear, i sorta thought it seemed a bit small, and figured you calculated at 100ah nnot 100w my bad This whole thing seems a very expensive way to have not very good portable power. You have never stated why you must have a fuel cell. Would you care to enlighten us? tom K0TAR well if one had to buy the jado it might be expensive, i can get one much cheeper than list and somone here posted an incorrect list price anyways , - then again if you add up the total cost of the competition you'd at worst case be in the ball park the goal was at first to power a hf/rig 100w tx for a few days on a backup power source looking at batteries/fuelcells i realized this is to much load so i figured my 2m righ on low pwr is a compramise @1week at 100w tx, i started to put together on paper what i need, a pretty big charger lots of very big heavy batteries , and they are VERY expensive, if the batteries went 'low' and the power wasn't restored say an extended blackout then the battery life goes down the tubes now i live in an apt, so too many batteries even if free arent practical code prevents me from using a generator in the building, so would the coop board, and the noise, smell vibration and mostly a generator running would attract 'undesiables' it would be kinda cheep and storing say desil wouldn't be a big deal if say i had a pvt house again thou getting extra fuel in a extended blackout would be an issue i had a demo of this fuel cell i was really impressed, is the cost and power output totally there no i guess not a few years from now prob but the cost of the fuel cell unit alone is comparable to the battery cost and i don't have to worry about the space, and other issues associated w/batteries i can get a small tank of hydrogen that would power the unit for longer than i was planning for it's cheep and i can get it very easy even if theyre was an extended blackout (details omitted) it's quite meets code, very small, very light dosn't pollute or stink seemed rather sexy the jado can also be powered from small cartridges making the unit selfcontained and very portable, however this isn't a requirement of mine but cool benni the only con for me, seems to be a)not totally going to give me 100w at full load b) i wish the unit was more than a puny 100w the larger units i would have to pay full list for and are therefore outta reach so solar /wind again might be nice in a pvt home but nothing i'd rely on it usually starts simple, i wanted somthing better than battery power much appreciation and mostly also because i like to tinker and learn seems like somthing cool to play with and experiment |
ans calculations/ fuel cell battery buffer or cap?
ml wrote:
well if one had to buy the jado it might be expensive, i can get one much cheeper than list and somone here posted an incorrect list price anyways , - then again if you add up the total cost of the competition you'd at worst case be in the ball park the goal was at first to power a hf/rig 100w tx for a few days on a backup power source looking at batteries/fuelcells i realized this is to much load so i figured my 2m righ on low pwr is a compramise @1week at 100w tx, i started to put together on paper what i need, a pretty big charger lots of very big heavy batteries , and they are VERY expensive, if the batteries went 'low' and the power wasn't restored say an extended blackout then the battery life goes down the tubes now i live in an apt, so too many batteries even if free arent practical code prevents me from using a generator in the building, so would the coop board, and the noise, smell vibration and mostly a generator running would attract 'undesiables' it would be kinda cheep and storing say desil wouldn't be a big deal if say i had a pvt house again thou getting extra fuel in a extended blackout would be an issue i had a demo of this fuel cell i was really impressed, is the cost and power output totally there no i guess not a few years from now prob but the cost of the fuel cell unit alone is comparable to the battery cost and i don't have to worry about the space, and other issues associated w/batteries i can get a small tank of hydrogen that would power the unit for longer than i was planning for it's cheep and i can get it very easy even if theyre was an extended blackout (details omitted) it's quite meets code, very small, very light dosn't pollute or stink seemed rather sexy the jado can also be powered from small cartridges making the unit selfcontained and very portable, however this isn't a requirement of mine but cool benni the only con for me, seems to be a)not totally going to give me 100w at full load b) i wish the unit was more than a puny 100w the larger units i would have to pay full list for and are therefore outta reach so solar /wind again might be nice in a pvt home but nothing i'd rely on it usually starts simple, i wanted somthing better than battery power much appreciation and mostly also because i like to tinker and learn seems like somthing cool to play with and experiment Ok, I have applied a simple power budget to what you stated your original desire was, as opposed to your cut down 2m 5W system. Using a rig I own, an FT-897, on HF. Assume 90% receive at 1 amp. Assume 10% transmit at 15 amps with 100 watts output, (measured as opposed to the 22 amps claimed in the docs) This gives 2.4 amps average consumption. (Check my math, the doctor did a lot during my pre-op today) 1 week is 168 hours which gives us 403 ampere hours. 100AH deep cycle batteries are around 100 each (or less), So that's about $400 for all the batteries you need for a week without sleep. A modern top of the line charger, such as produced by Schumacher, is less than $100, does automatic desulfation, will charge at 50 amps or greater, and weighs about 6 pounds. So now we are at under 500 dollars for an emergency power for any ham that needs to run an HF rig for a whole week. I just don't see why you want to use the fuel cell, it makes no sense. tom K0TAR |
ans calculations/ fuel cell battery buffer or cap?
Tom Ring wrote:
. . . 1 week is 168 hours which gives us 403 ampere hours. . . . which at 13.6 volts is about 5480 watt-hours. This is the energy storage requirement. The OP asked about using a capacitor. The energy stored in a capacitor is C * V^2 / 2. For capacitance in farads and voltage in volts, the result is joules, or watt-seconds -- you need 5480 * 3600 ~ 20,000,000 joules in round numbers. So suppose you wanted to store this same amount of energy in a capacitor, and you had a switching regulator which would handle 50 volts maximum input voltage. Solving for C, assuming it's charged to 50 volts, C = 20,000,000 * 2 / (50^2) = 16,000 farads. This assumes you can get all the energy out of the capacitor, which requires your regulator to work down to zero volts. But you'll get 3/4 of the energy out of it if your regulator cuts off at 25 volts, 7/8 if it cuts off at 12.5 volts, etc. How does that sound? Roy Lewallen, W7EL |
cap/ ans calculations/ fuel cell battery buffer or cap?
In article ,
Roy Lewallen wrote: Tom Ring wrote: . . . 1 week is 168 hours which gives us 403 ampere hours. . . . which at 13.6 volts is about 5480 watt-hours. This is the energy storage requirement. The OP asked about using a capacitor. The energy stored in a capacitor is C * V^2 / 2. For capacitance in farads and voltage in volts, the result is joules, or watt-seconds -- you need 5480 * 3600 ~ 20,000,000 joules in round numbers. So suppose you wanted to store this same amount of energy in a capacitor, and you had a switching regulator which would handle 50 volts maximum input voltage. Solving for C, assuming it's charged to 50 volts, C = 20,000,000 * 2 / (50^2) = 16,000 farads. This assumes you can get all the energy out of the capacitor, which requires your regulator to work down to zero volts. But you'll get 3/4 of the energy out of it if your regulator cuts off at 25 volts, 7/8 if it cuts off at 12.5 volts, etc. How does that sound? Roy Lewallen, W7EL well i guess it sounds like i wont have any 16,000 farad cap's stacked up in my myplace anytime soon, but i understand the math behind it now thanks perhaps i'll just get a small cap to handle a brief second keydown dip smooth things out a bit thanks |
preop/ ans calculations/ fuel cell battery buffer or cap?
In article ,
Tom Ring wrote: ml wrote: omitted) it's quite meets code, very small, very light dosn't pollute or stink seemed rather sexy the jado can also be powered from small cartridges making the unit selfcontained and very portable, however this isn't a requirement of mine but cool benni the only con for me, seems to be a)not totally going to give me 100w at full load b) i wish the unit was more than a puny 100w the larger units i would have to pay full list for and are therefore outta reach so solath and experiment Ok, I have applied a simple power budget to what you stated your original desire was, as opposed to your cut down 2m 5W system. Using a rig I own, an FT-897, on HF. Assume 90% receive at 1 amp. Assume 10% transmit at 15 amps with 100 watts output, (measured as opposed to the 22 amps claimed in the docs) This gives 2.4 amps average consumption. (Check my math, the doctor did a lot during my pre-op today) 1 week is 168 hours which gives us 403 ampere hours. 100AH deep cycle batteries are around 100 each (or less), So that's about $400 for all the batteries you need for a week without sleep. A modern top of the line charger, such as produced by Schumacher, is less than $100, does automatic desulfation, will charge at 50 amps or greater, and weighs about 6 pounds. So now we are at under 500 dollars for an emergency power for any ham that needs to run an HF rig for a whole week. I just don't see why you want to use the fuel cell, it makes no sense. tom K0TAR tom, am i to understand you had some surgery today? if so, i hope all is well with you and taking the time to write is appreciated i am guessing roy's calculation of the total ampre hrs needed is closer to being correct, but it's 5am and i kinda don't know how to calculate that so i dunno as stated in my earlier post i don't have the formulas so i can't act to confirm but i nod my head and presume it's all correct based on roys math you are correct about what the rig is doing mine is exactly simular i would calculate based on 20amps re your last comments on why i would want a fuel cell, it should be very clear in all my many posts 5480 watt-hours of battery is more $$ and large than i have practical room for i can get the fuel cell for practically nothing and i just thought it might be able to offer some useful power to top off a battery to provide some b/u power why not? and also be a fun experiment it runs quiet , clean and i can get all the fuel i want free always, i would never be able to get fossel fuels in a blackout or other emerg so now i inch a drop closer knowing how many what hours my original abandoned goal would draw , however my current stated goal is to just power my 5w tx output(draws4amps) 2m mobile rig and try to calculate how much the battery would be drained in a 1min tx and then see if the 12v 7amps comming out of the jado would recharge it fast enough i believe that is what must be calculated for just not sure how do it, unless you still say a 7amp battery is still 'ok' my goal was to be able to calculate so a 7amp battery(or what ever is needed optically this seems like a too low a #)) w/a 1min 4amp load would be ??%drained then based on manuf spec's for the battery we could calculate how much power &time would be needed to top it back off then it would be simple enough to see if the output of the jado is sufficient i think thats all thats needed i think that's simple but i dunno how to calculate it thanks all i really wanted to do |
ans calculations/ fuel cell battery buffer or cap?
"ml" wrote in message ... now i live in an apt, so too many batteries even if free arent practical code prevents me from using a generator in the building, so would the coop board, and the noise, smell vibration and mostly a generator running would attract 'undesiables' it would be kinda cheep and storing say desil wouldn't be a big deal if say i had a pvt house again thou getting extra fuel in a extended blackout would be an issue i bet you also find that storing explosive gasses in an apartment are also against code. and laywers would probably consider a fuel cell a generator also. your best bet is to just keep a few gell cells around to run your vhf on low power, you can get many hours on a charge... when one dies, swap for another one, take it out to your car, charge it from there, and bring it back in. remember, in an emergency you most likely won't be making long transmissions anyway, first because there won't be that many locals to talk to because most of them won't have power... repeaters will be tied up with emergency traffic, and unless you are a net control you should mostly be listening. |
ans calculations/ fuel cell battery buffer or cap?
In article ,
"Dave" wrote: i bet you also find that storing explosive gasses in an apartment are also against code. and laywers would probably consider a fuel cell a generator also. Well not really, as a lot of apartments have Explosive GAS piped right into them..... Never heard of Natural Gas, or even Propane, I guess.... Both are Extremely Explosive, when mixed with air in the correct ratio.... Duh..... |
ans calculations/ fuel cell battery buffer or cap?
Check a lease on an apartment, or the condo codes, storing propane on or in your
residence or even on your deck is a violation. You wrote: In article , "Dave" wrote: i bet you also find that storing explosive gasses in an apartment are also against code. and laywers would probably consider a fuel cell a generator also. Well not really, as a lot of apartments have Explosive GAS piped right into them..... Never heard of Natural Gas, or even Propane, I guess.... Both are Extremely Explosive, when mixed with air in the correct ratio.... Duh..... |
ans calculations/ fuel cell battery buffer or cap?
On Fri, 27 Oct 2006 01:59:24 GMT, ml wrote:
it usually starts simple, i wanted somthing better than battery power Hi Myles, You are suffering from easy access to an answer to the wrong question. First, investigate/research DC-DC converters. We've been through this once before, haven't we? The various storage methods you've been cycling through Cell/Battery/Cap all have different voltage parameters compared to the eventual load. True, the battery naturally fits that 13.6V requirement, but it eventually fades. With the right DC-DC converter, you can accommodate almost any scenario you've described and efficiently transform to a steady reliable voltage source capable of meeting the current load. With the right DC-DC converter, you can also meet the requirements for recharging a cap or a battery from any other source (Cell/Battery/Cap). Flexibility allows you to move from any power source to another and still supply your load reliably. 73's Richard Clark, KB7QHC |
preop/ ans calculations/ fuel cell battery buffer or cap?
ml wrote: In article , Tom Ring wrote: ml wrote: omitted) it's quite meets code, very small, very light dosn't pollute or stink seemed rather sexy the jado can also be powered from small cartridges making the unit selfcontained and very portable, however this isn't a requirement of mine but cool benni the only con for me, seems to be a)not totally going to give me 100w at full load b) i wish the unit was more than a puny 100w the larger units i would have to pay full list for and are therefore outta reach so solath and experiment Ok, I have applied a simple power budget to what you stated your original desire was, as opposed to your cut down 2m 5W system. Using a rig I own, an FT-897, on HF. Assume 90% receive at 1 amp. Assume 10% transmit at 15 amps with 100 watts output, (measured as opposed to the 22 amps claimed in the docs) This gives 2.4 amps average consumption. (Check my math, the doctor did a lot during my pre-op today) 1 week is 168 hours which gives us 403 ampere hours. 100AH deep cycle batteries are around 100 each (or less), So that's about $400 for all the batteries you need for a week without sleep. A modern top of the line charger, such as produced by Schumacher, is less than $100, does automatic desulfation, will charge at 50 amps or greater, and weighs about 6 pounds. So now we are at under 500 dollars for an emergency power for any ham that needs to run an HF rig for a whole week. I just don't see why you want to use the fuel cell, it makes no sense. tom K0TAR tom, am i to understand you had some surgery today? if so, i hope all is well with you and taking the time to write is appreciated i am guessing roy's calculation of the total ampre hrs needed is closer to being correct, but it's 5am and i kinda don't know how to calculate that so i dunno as stated in my earlier post i don't have the formulas so i can't act to confirm but i nod my head and presume it's all correct based on roys math you are correct about what the rig is doing mine is exactly simular i would calculate based on 20amps re your last comments on why i would want a fuel cell, it should be very clear in all my many posts 5480 watt-hours of battery is more $$ and large than i have practical room for i can get the fuel cell for practically nothing and i just thought it might be able to offer some useful power to top off a battery to provide some b/u power why not? and also be a fun experiment it runs quiet , clean and i can get all the fuel i want free always, i would never be able to get fossel fuels in a blackout or other emerg so now i inch a drop closer knowing how many what hours my original abandoned goal would draw , however my current stated goal is to just power my 5w tx output(draws4amps) 2m mobile rig and try to calculate how much the battery would be drained in a 1min tx and then see if the 12v 7amps comming out of the jado would recharge it fast enough i believe that is what must be calculated for just not sure how do it, unless you still say a 7amp battery is still 'ok' my goal was to be able to calculate so a 7amp battery(or what ever is needed optically this seems like a too low a #)) w/a 1min 4amp load would be ??%drained then based on manuf spec's for the battery we could calculate how much power &time would be needed to top it back off then it would be simple enough to see if the output of the jado is sufficient i think thats all thats needed i think that's simple but i dunno how to calculate it thanks all i really wanted to do If your rig draws 4 amps (I assume that's on transmit; it would be an awful lot of power for a modern receiver), and the fuel cell can put out 7 amps continuously albeit at slightly reduced voltage, and I assume it can put out 4 amps at less of a reduction, why are you worried about it? Unless you are VERY long-winded with your transmissions, a small 7amp-hour sealed lead acid battery would give you a couple hours operating time even if it wasn't being continuously recharged. I'd actually opt instead for some voltage stabilization at the fuel cell output: a buck-boost regulator would do it. If you trust the fuel cell to do its job, then trust it. If you don't, then provide a backup. So what I read between the lines you've written is that you're going to get this fuel cell, but you don't really trust it. You don't even trust it to come close to what are apparently its published ratings. Pretty much all the formulas you need to figure all this stuff out: power = voltage times current (watts = volts * amps) energy = power times time (joules = watts * seconds) -- total energy needed = sum of (each current times the length of time that current is drawn) amp-hours = amps * hours = amps * seconds / 3600sec/hr battery energy storage in watt-hours = amp-hour rating * volts (assuming full charge) battery energy storage in joules = amp-hour rating * volts * 3600 sec/hour capacitor energy storage = (initial charge voltage)^2 * capacitance / 2 joules = watt-seconds = volts^2 * farads / 2 watt-hours = joules/3600 = volts^2 * farads / 7200 Where is it that you can get a license without knowing at least this much? Why so much trouble with the concepts of power and energy calculated from current, voltage and time? (Why is this posted to an antennas newsgroup?) Cheers, Tom |
preop/ ans calculations/ fuel cell battery buffer or cap?
ml wrote: In article , Tom Ring wrote: ml wrote: omitted) it's quite meets code, very small, very light dosn't pollute or stink seemed rather sexy the jado can also be powered from small cartridges making the unit selfcontained and very portable, however this isn't a requirement of mine but cool benni the only con for me, seems to be a)not totally going to give me 100w at full load b) i wish the unit was more than a puny 100w the larger units i would have to pay full list for and are therefore outta reach so solath and experiment Ok, I have applied a simple power budget to what you stated your original desire was, as opposed to your cut down 2m 5W system. Using a rig I own, an FT-897, on HF. Assume 90% receive at 1 amp. Assume 10% transmit at 15 amps with 100 watts output, (measured as opposed to the 22 amps claimed in the docs) This gives 2.4 amps average consumption. (Check my math, the doctor did a lot during my pre-op today) 1 week is 168 hours which gives us 403 ampere hours. 100AH deep cycle batteries are around 100 each (or less), So that's about $400 for all the batteries you need for a week without sleep. A modern top of the line charger, such as produced by Schumacher, is less than $100, does automatic desulfation, will charge at 50 amps or greater, and weighs about 6 pounds. So now we are at under 500 dollars for an emergency power for any ham that needs to run an HF rig for a whole week. I just don't see why you want to use the fuel cell, it makes no sense. tom K0TAR tom, am i to understand you had some surgery today? if so, i hope all is well with you and taking the time to write is appreciated i am guessing roy's calculation of the total ampre hrs needed is closer to being correct, but it's 5am and i kinda don't know how to calculate that so i dunno as stated in my earlier post i don't have the formulas so i can't act to confirm but i nod my head and presume it's all correct based on roys math you are correct about what the rig is doing mine is exactly simular i would calculate based on 20amps re your last comments on why i would want a fuel cell, it should be very clear in all my many posts 5480 watt-hours of battery is more $$ and large than i have practical room for i can get the fuel cell for practically nothing and i just thought it might be able to offer some useful power to top off a battery to provide some b/u power why not? and also be a fun experiment it runs quiet , clean and i can get all the fuel i want free always, i would never be able to get fossel fuels in a blackout or other emerg so now i inch a drop closer knowing how many what hours my original abandoned goal would draw , however my current stated goal is to just power my 5w tx output(draws4amps) 2m mobile rig and try to calculate how much the battery would be drained in a 1min tx and then see if the 12v 7amps comming out of the jado would recharge it fast enough i believe that is what must be calculated for just not sure how do it, unless you still say a 7amp battery is still 'ok' my goal was to be able to calculate so a 7amp battery(or what ever is needed optically this seems like a too low a #)) w/a 1min 4amp load would be ??%drained then based on manuf spec's for the battery we could calculate how much power &time would be needed to top it back off then it would be simple enough to see if the output of the jado is sufficient i think thats all thats needed i think that's simple but i dunno how to calculate it thanks all i really wanted to do If your rig draws 4 amps (I assume that's on transmit; it would be an awful lot of power for a modern receiver), and the fuel cell can put out 7 amps continuously albeit at slightly reduced voltage, and I assume it can put out 4 amps at less of a reduction, why are you worried about it? Unless you are VERY long-winded with your transmissions, a small 7amp-hour sealed lead acid battery would give you a couple hours operating time even if it wasn't being continuously recharged. I'd actually opt instead for some voltage stabilization at the fuel cell output: a buck-boost regulator would do it. If you trust the fuel cell to do its job, then trust it. If you don't, then provide a backup. So what I read between the lines you've written is that you're going to get this fuel cell, but you don't really trust it. You don't even trust it to come close to what are apparently its published ratings. Pretty much all the formulas you need to figure all this stuff out: power = voltage times current (watts = volts * amps) energy = power times time (joules = watts * seconds) -- total energy needed = sum of (each current times the length of time that current is drawn) amp-hours = amps * hours = amps * seconds / 3600sec/hr battery energy storage in watt-hours = amp-hour rating * volts (assuming full charge) battery energy storage in joules = amp-hour rating * volts * 3600 sec/hour capacitor energy storage = (initial charge voltage)^2 * capacitance / 2 joules = watt-seconds = volts^2 * farads / 2 watt-hours = joules/3600 = volts^2 * farads / 7200 Where is it that you can get a license without knowing at least this much? Why so much trouble with the concepts of power and energy calculated from current, voltage and time? (Why is this posted to an antennas newsgroup?) Cheers, Tom |
preop/ ans calculations/ fuel cell battery buffer or cap?
K7ITM wrote:
-- total energy needed = sum of (each current times the length of time that current is drawn) You probably meant to say current times time is total charge. 73 de AC6XG |
ans calculations/ fuel cell battery buffer or cap?
Roy Lewallen wrote in
: Tom Ring wrote: . . . 1 week is 168 hours which gives us 403 ampere hours. . . . which at 13.6 volts is about 5480 watt-hours. This is the energy storage requirement. The OP asked about using a capacitor. The energy stored in a capacitor is C * V^2 / 2. For capacitance in farads and voltage in volts, the result is joules, or watt-seconds -- you need 5480 * 3600 ~ 20,000,000 joules in round numbers. So suppose you wanted to store this same amount of energy in a capacitor, and you had a switching regulator which would handle 50 volts maximum input voltage. Solving for C, assuming it's charged to 50 volts, C = 20,000,000 * 2 / (50^2) = 16,000 farads. This assumes you can get all the energy out of the capacitor, which requires your regulator to work down to zero volts. But you'll get 3/4 of the energy out of it if your regulator cuts off at 25 volts, 7/8 if it cuts off at 12.5 volts, etc. How does that sound? Roy Lewallen, W7EL Send that to me in CW and I'll have a look at it. SC |
preop/ ans calculations/ fuel cell battery buffer or cap?
Jim Kelley wrote: K7ITM wrote: -- total energy needed = sum of (each current times the length of time that current is drawn) You probably meant to say current times time is total charge. 73 de AC6XG Yeah, probably something like that. ;-) Actually, what I meant to write was more like: -- total energy needed = voltage * sum of (each current times the length of time that current is drawn. Lesseee...unit analysis...volts * amps * time. OK, that looks better. Thanks, Jim. Cheers, Tom |
ans calculations/ fuel cell battery buffer or cap?
You wrote:
Well not really, as a lot of apartments have Explosive GAS piped right into them..... Never heard of Natural Gas, or even Propane, I guess.... Both are Extremely Explosive, when mixed with air in the correct ratio.... Duh..... You will find that from a legal perspective that natural gas piped in is not at all the same as storing a tank of hydrogen. Natural gas and propane are very highly regulated as to installation, equipment attached, etc. Very different than your tank of H2 will be. tom K0TAR |
fuel cell battery buffer or cap?
On Thu, 26 Oct 2006 08:53:31 -0700, Jim Kelley
wrote: 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 Very interesting. But Seems like those fuel canisters are just a bit on the pricey side. And what fuel do they indeed use? Complete lack of info on that. I see the website mentions refill stations. What kind of power do those use? How do they work. Tony |
fuel cell battery buffer or cap?
On Sat, 28 Oct 2006 16:01:03 GMT, Tony VE6MVP
wrote: Seems like those fuel canisters are just a bit on the pricey side. When I run the numbers through I get N-Gen at $1000 and Honda EU1000i at $790. Close enough for now. But the fuel is much different. - N-Stor130 is 130 W-h for a cost of $450. But the Honda fuel consumption is 3.8 hours at rated continuous duty of 900 watts. Or a 0.6 US gal tank of gas produces 3420 W-h. That's about $2. So 130 W-h for $450 or 3420 W-h for $2. Unless you really, really need that absolute quiet of the fuel cell or have unusual conditions such as the space shuttle then it's a no brainer to me. Tony |
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