@mopowah How much extra power would you get for what extra increase in lens thickness and collection surface area? Like it or not, some things are just not technically feasible.
One aspect not mentioned, is that the light spectrum of a neon tube and the sun are not the same. That is paramount to know which spectrum your solar device can use.
Low power solar devices like calculators tend to use amorphous cells. I'm intregued by the claims that amorphous panels don't need sunlight, just daylight! Sounds like nonsense to me so I need to do some comparisons between silicon wafer and amorphous at different light levels. Maybe at low light levels amorphous really does beat crystalline.
Oh OK! Maybe you could someday run a video blog about these super capacitors (1Farad and beyond), their features and tradeoffs. They could be useful for ultra low power applications I think.
Yes, that's possible, but then it's not a practical product. What happens when it's FLAT and you want to use it right away? Calculators are only useful when they are instantly available, and no one wants yet another device they have to remember to charge.
The amount of power that a PV module can generate is directly related to the intensity of the light incident on the module. As the intensity of the light under a streetlight is a VERY tiny fraction of that in full sun, a PV module can only produce a correspondingly tiny fraction of it's rated power. There will also be additional power reduction due to the inhomogeneity of the light.
I think part of the problem is also that spectrum of fluerescent tubes (and LEDs) isn't good for Si cells. They like more the infrared part, so it should work better under incandescent sources.
Hi Dave, this is an idea... you can still use the solar cells and add a huge capacitor to store energy. Just use the same cells and charge the capacitor with direct Sun light outside. You can get a 1 Farad capacitor from some web sites. Yes, there are 1F capacitors :D
@mopowah It is a credit card sized scientific calculator, there is no stand, there is no cabinet. If you had a battery in the stand you would NEVER need solar. A couple of AA cells would last their shelf life, so solar would be pointless. You need more than just the right frame of mind, you need to meet technical power consumption specifications using available technology. It is simply not feasible.
You could increase the available area for a solar panel by using capacitive buttons behind a large array of solar panels and then put some perspex over the solar panels with the button outlines printed on them. I think this would give you the grunt needed to run the LCD.
Dave, you should look for PV cells that are optimized for indoor use, rather than high efficiency in sunlight. I think there are some PV cells that are designed to use the wavelengths put out by fluorescent lamps.
I think I've found my next project. Some of those solar cells in parallel with some AA batteries with a usb connector to charge my cell phone and tablet. I haven't played with solar cells since I was a kid. Thanks Dave for these informative videos. I haven't seen them all but I plan to.
I do not expect the absolute maximum efficiency cap of 100% to go away any time soon.
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Well maybe you can use some buffer, like slim supercap, or li-poly battery, that can be really all shapes and flexible. If the life on fully charged acu can be up to hours, adding usb cable to charge + some solar cells at the back side of science calc is a good idea. But no cheap i guess. Still better to invest in regular standards. I'm a huge fun of eco-power myself, I'd problably buy one if constructed like this ;-)
Perhaps 25% of the compact flourescent lamps I have purchased recently have failed within a couple of months. Considering how much energy must go into manufacturing one, I would like to know at what lifetime the "energy saved versus normal bulb" crosses the "energy consumed to make it versus normal bulb".... I suspect it's pretty far out meaning these only make sense for long-burning applications, but they also have to stay cool, or else they fail. A difficult combination.
For a similar system I found a rechargeable button cell 1.2V 300maH. I cant remember what it was. But I used a DC/DC converter to go from the solar cell to the battery... in parallel with the circuit... it worked for a bit (cheap IC's)... but then the project was scrapped
In my experience, solar calculators need incandescent light to work properly. That one you have that's working might be specially tuned to fluorescent lighting though.
@EEVblog Depending on the size of the screen you could use a cabinet or a stand and integrate the battery and solar cells into the stand or cabinet it is possible I have no paper to certify me as much of anything but I am perfectly capable of deriving solutions for things with my limited knowledge. I would almost like to prove this thing is possible but do not have the faintest on what the best hardware to accomplish the task is or the code that would be required...
Hello Dave, A small error of unity i think. You should use lux unity and not lumen unity when speaking about the sun, as lumen is related to total flux getting out of a luminous source regarding to human eyes sensibility (let's say infinite for the sun ;)), and lux is simply related to a flux of light that a surface receives (lumen/m2). The best way should be to use a power meter device that gives light power received by meter square and relative to the spectrum of sun. As the power of your solar cell is given for a power illumination of 1000 W/m2 at 25°C and 45° of light angle, just use the hypothesis of a linear relation, and make the calculation to get an assessment of the power you could get. An other remark, i think that amorphous technology absorbs better diffused light, like indoor light, than mono and polycristalline.
For better indoor collection organic PV (DSSC Dye Sensitized for one)is supposed to perform better with indoor light, given the correct chemistry inside. I am curious on weather you are still interested in this project I want to see it done I know it is possible how many cells and how much surface area would you need?
You've also just demonstrated one of the most important reasons for using decibel units, which I don't think you mentioned in your decibel video, it's that our senses and many other biological processes, work at the decibel, or log, scale. Basic example, octaves in music--spectrums plotted on linear scale don't seem right, on a log scale, it does.
@mopowah Nope, sorry, it's just not possible, regardless of how much you hope it might be. If you have a way to magically increase the output from the same surface area solar cell with the same thickness, by at least an order of magnitude or more, please share it. Some things just just aren't technically possible using current technology, and you can do the basic math and measurements to easily prove that.
@EEVblog This is a practical product it could be made to work I think you need to investigate this one how big is the dot matrix LCD you are using I'd really like to know I think this project is indeed a work in progress with the right frame of mind it could be done. If you sold it with a cabinet that collected the solar or a stand it was on where the stand was collecting the solar and integrated a battery into the stand I think it is without a doubt instant and possible!!!
I understand the lumen to current calculation (i.e. 1000x more lumen outside than inside, so 1000x more current ), but where does the 90db (30000 to 1) math factor in?
I am curious if you have tried any daylight spectrum cfls to see if they make a difference due to the higher color temperature. I type this from my solar powered keyboard the Logitech K750 as I speak and realize that anything indoor solar could be made a possibility with a little thought here is another suggestion sell the TV with a that has a frame that it mounts to built with an enclosed cabinet for your bluray the top will be covered by solar cells and have an XL TV frame covered in them 2
Would it be possible to use something like 2x 5v 1F capacitor in conjunction with the solar cells then an on off switch so it would leave the cap charged? If you left the calculator on a desk or table ect the cap would slowly charge, or would leakage ect prevent that from being practical?
great video would really like to get some of those mono solar strips . I can't find them . keep up the good work . would very much like to meet you in person I'd pay to listen to you tell us interesting things . thanks man . from the UK
Unless the laws of physics change, it will still be impossible to get more energy than is available in the light that hits the module. The module would just convert more of the light hitting it into electricity.
they will of course. its not the efficiency that counts, its the cost. oil costs permanently but light is free. Id rather get 100w for nothing than 250w for money.
Based on the power output of the Saturn V's F1 engines, you'd need 17.088955375 Gigavolts to equal that power with a current of 0.012 Amps to get to the moon.
Have you also thought of the possibility of using a bunch of nano sized magnifying glasses and setting the solar cells a bit deeper if you could use nano sized magnifying glasses to amplify and concentrate more of the observed light to be projected at the cells you could likely increase your output and wind up getting a nice increase in power collected who knows use some of these last 3 ideas or all together and bingo your project is possible once again! Don't give up practicality 4 technicality
That would be impossible as there is only a tiny fraction of the available light energy available in moonlight as there is in sunlight. If the light on a PV module is only 1/10,000th that of sunlight, then said module can only produce 1/10,000th its rated power. This means that your 300W module can only produce 30mW (0.03W). To say otherwise is to get into the realm of free energy bullshit.
Not sure about all details of your project, what about having a small decent rechargeable battery? Then the solar to charge it? Does it need to be solar only? I assume you want it to be used even while charging which I assume would be an issue again
The automated youtube captions on this video had me rolling.
@mopowah How much extra power would you get for what extra increase in lens thickness and collection surface area? Like it or not, some things are just not technically feasible.
Yes, it does. All solar cells shipped to Australia must have the positive & negative leads reversed by law. Beware gray market imports!
wtf?
Dave's nuggets of wisdom... Thanks for making great videos! :) Greetings from germany.
Incandescent bulbs are now BANNED in Australia! Oh boy, I feel a rant coming on!
How do you feel now, almost a decade later?
One aspect not mentioned, is that the light spectrum of a neon tube and the sun are not the same. That is paramount to know which spectrum your solar device can use.
Low power solar devices like calculators tend to use amorphous cells. I'm intregued by the claims that amorphous panels don't need sunlight, just daylight! Sounds like nonsense to me so I need to do some comparisons between silicon wafer and amorphous at different light levels. Maybe at low light levels amorphous really does beat crystalline.
Oh OK!
Maybe you could someday run a video blog about these super capacitors (1Farad and beyond), their features and tradeoffs.
They could be useful for ultra low power applications I think.
Yes, that's possible, but then it's not a practical product. What happens when it's FLAT and you want to use it right away? Calculators are only useful when they are instantly available, and no one wants yet another device they have to remember to charge.
The amount of power that a PV module can generate is directly related to the intensity of the light incident on the module. As the intensity of the light under a streetlight is a VERY tiny fraction of that in full sun, a PV module can only produce a correspondingly tiny fraction of it's rated power. There will also be additional power reduction due to the inhomogeneity of the light.
I think part of the problem is also that spectrum of fluerescent tubes (and LEDs) isn't good for Si cells. They like more the infrared part, so it should work better under incandescent sources.
Hi Dave, this is an idea... you can still use the solar cells and add a huge capacitor to store energy.
Just use the same cells and charge the capacitor with direct Sun light outside.
You can get a 1 Farad capacitor from some web sites. Yes, there are 1F capacitors :D
@mopowah It is a credit card sized scientific calculator, there is no stand, there is no cabinet. If you had a battery in the stand you would NEVER need solar. A couple of AA cells would last their shelf life, so solar would be pointless.
You need more than just the right frame of mind, you need to meet technical power consumption specifications using available technology. It is simply not feasible.
You could increase the available area for a solar panel by using capacitive buttons behind a large array of solar panels and then put some perspex over the solar panels with the button outlines printed on them. I think this would give you the grunt needed to run the LCD.
Since the surface of the watch is a PCB if you are willing to re design the PCB bit you can solder the Solar cells around the perimeter.
Digikey are out of stock :(
Show more of your project! Take us along the journey as you've started too with the solar idea. So whats your next step?
"You can fly to the moon on 12mA!"
Dave, you should look for PV cells that are optimized for indoor use, rather than high efficiency in sunlight. I think there are some PV cells that are designed to use the wavelengths put out by fluorescent lamps.
Would be really cool if you did a video on a low power project like a thermostat with an LCD that can run for years on a AA batt.
I think I've found my next project. Some of those solar cells in parallel with some AA batteries with a usb connector to charge my cell phone and tablet. I haven't played with solar cells since I was a kid.
Thanks Dave for these informative videos. I haven't seen them all but I plan to.
I seem to remember from where that the old school light cells work better in lower light conditions compared with the new one. Could be wrong.
I do not expect the absolute maximum efficiency cap of 100% to go away any time soon.
Well maybe you can use some buffer, like slim supercap, or li-poly battery, that can be really all shapes and flexible. If the life on fully charged acu can be up to hours, adding usb cable to charge + some solar cells at the back side of science calc is a good idea. But no cheap i guess. Still better to invest in regular standards. I'm a huge fun of eco-power myself, I'd problably buy one if constructed like this ;-)
Perhaps 25% of the compact flourescent lamps I have purchased recently have failed within a couple of months.
Considering how much energy must go into manufacturing one, I would like to know at what lifetime the "energy saved versus normal bulb" crosses the "energy consumed to make it versus normal bulb"....
I suspect it's pretty far out meaning these only make sense for long-burning applications, but they also have to stay cool, or else they fail. A difficult combination.
Colleague of mine had one like that. Plug into the cigarette lighter nothing happens. We tested it and they wired it the Australian way!
Just connect the solar cell directly to the LED, do no use any resistor.
3mA and 2V should be enough to see a little light coming from the LED.
For a similar system I found a rechargeable button cell 1.2V 300maH. I cant remember what it was. But I used a DC/DC converter to go from the solar cell to the battery... in parallel with the circuit... it worked for a bit (cheap IC's)... but then the project was scrapped
In my experience, solar calculators need incandescent light to work properly. That one you have that's working might be specially tuned to fluorescent lighting though.
@EEVblog Depending on the size of the screen you could use a cabinet or a stand and integrate the battery and solar cells into the stand or cabinet it is possible I have no paper to certify me as much of anything but I am perfectly capable of deriving solutions for things with my limited knowledge. I would almost like to prove this thing is possible but do not have the faintest on what the best hardware to accomplish the task is or the code that would be required...
Hello Dave,
A small error of unity i think. You should use lux unity and not lumen unity when speaking about the sun, as lumen is related to total flux getting out of a luminous source regarding to human eyes sensibility (let's say infinite for the sun ;)), and lux is simply related to a flux of light that a surface receives (lumen/m2). The best way should be to use a power meter device that gives light power received by meter square and relative to the spectrum of sun. As the power of your solar cell is given for a power illumination of 1000 W/m2 at 25°C and 45° of light angle, just use the hypothesis of a linear relation, and make the calculation to get an assessment of the power you could get.
An other remark, i think that amorphous technology absorbs better diffused light, like indoor light, than mono and polycristalline.
For better indoor collection organic PV (DSSC Dye Sensitized for one)is supposed to perform better with indoor light, given the correct chemistry inside. I am curious on weather you are still interested in this project I want to see it done I know it is possible how many cells and how much surface area would you need?
Hello after 11.5 years.
You've also just demonstrated one of the most important reasons for using decibel units, which I don't think you mentioned in your decibel video, it's that our senses and many other biological processes, work at the decibel, or log, scale. Basic example, octaves in music--spectrums plotted on linear scale don't seem right, on a log scale, it does.
@mopowah Nope, sorry, it's just not possible, regardless of how much you hope it might be. If you have a way to magically increase the output from the same surface area solar cell with the same thickness, by at least an order of magnitude or more, please share it.
Some things just just aren't technically possible using current technology, and you can do the basic math and measurements to easily prove that.
@EEVblog This is a practical product it could be made to work I think you need to investigate this one how big is the dot matrix LCD you are using I'd really like to know I think this project is indeed a work in progress with the right frame of mind it could be done. If you sold it with a cabinet that collected the solar or a stand it was on where the stand was collecting the solar and integrated a battery into the stand I think it is without a doubt instant and possible!!!
I understand the lumen to current calculation (i.e. 1000x more lumen outside than inside, so 1000x more current ), but where does the 90db (30000 to 1) math factor in?
I am curious if you have tried any daylight spectrum cfls to see if they make a difference due to the higher color temperature. I type this from my solar powered keyboard the Logitech K750 as I speak and realize that anything indoor solar could be made a possibility with a little thought here is another suggestion sell the TV with a that has a frame that it mounts to built with an enclosed cabinet for your bluray the top will be covered by solar cells and have an XL TV frame covered in them 2
For a minute, I was puzzled by what new technology a Flu-row tube was (I'm American).
Would it be possible to use something like 2x 5v 1F capacitor in conjunction with the solar cells then an on off switch so it would leave the cap charged?
If you left the calculator on a desk or table ect the cap would slowly charge, or would leakage ect prevent that from being practical?
oil is about 80% efficent and until solar panels reach around that level they will not be a real competiter
great video would really like to get some of those mono solar strips . I can't find them . keep up the good work . would very much like to meet you in person I'd pay to listen to you tell us interesting things . thanks man . from the UK
You can buy them from Digikey.
itd be cool to make a circuit that charged up, and once it got high enough power it powers the cpu for one operation, and uses E-ink for the screen.
Unless the laws of physics change, it will still be impossible to get more energy than is available in the light that hits the module. The module would just convert more of the light hitting it into electricity.
Nice to see a hit n miss. Coming from software side transitioning to the hardware. Nice to see some of the different things are just the same. >;)
The answer is simple, a solar powered device with a small rechargeable battery that you can charge outside!
Can a Li-Ion battery output energy and be recharged at the same time?
Shouldn't solar power in Australia generate negative voltage? Cause, you know, it's down under.
why don't you run your LCD with an arc reactor
great video
@EEVblog but just think all the extra mercury in the environment from the CFL bulbs!!!! we wont be able to eat any sea food at all soon =)
they will of course. its not the efficiency that counts, its the cost. oil costs permanently but light is free. Id rather get 100w for nothing than 250w for money.
My thoughts across the same line...
Based on the power output of the Saturn V's F1 engines, you'd need 17.088955375 Gigavolts to equal that power with a current of 0.012 Amps to get to the moon.
Haha, this old video applies perfectly on the recent solar roadways bullshit project.
Hahaha, yeah you are right :D
Have you also thought of the possibility of using a bunch of nano sized magnifying glasses and setting the solar cells a bit deeper if you could use nano sized magnifying glasses to amplify and concentrate more of the observed light to be projected at the cells you could likely increase your output and wind up getting a nice increase in power collected who knows use some of these last 3 ideas or all together and bingo your project is possible once again! Don't give up practicality 4 technicality
That would be impossible as there is only a tiny fraction of the available light energy available in moonlight as there is in sunlight. If the light on a PV module is only 1/10,000th that of sunlight, then said module can only produce 1/10,000th its rated power. This means that your 300W module can only produce 30mW (0.03W). To say otherwise is to get into the realm of free energy bullshit.
If it's worth doing, it's worth overdoing... slap ten of those on and call it good. ^_^
Not sure about all details of your project, what about having a small decent rechargeable battery? Then the solar to charge it? Does it need to be solar only? I assume you want it to be used even while charging which I assume would be an issue again
Moonlight is more like 1/100,000th as bright as full sun.
You can't. Those solar pannels are about 2 volts and only a few milliamps
90dB is a billion to one ratio
@SPLEclipse It's ok, we can forgive you :->
@EEVblog well there banned for household use anyway
SUPER CAPS, or ULTRA CAPS
europe follows... 1 september 2012
Go to inplix page if you'd like to know how to build it. Great solutions for everyone I think