That's fascinating, but the best part was that laugh of pure joy when you found the whole idea a tally worked. They have a transparent panel that apparently uses available IR and UV in daylight to generate electricity, while visible light passes through. They are using it mostly for greenhouses, if I am not mistaken, but this could be applied to house windows as well.
Yellow is interesting because IIRC photosynthesis operates off of red and blue. So this could lead to solar electric that does not interfere with agriculture, and greenhouses that produce both plants and electricity.
Acrylic can be bought in two ways. Light hits surface and directs out the edges, or the opposite where light enters the edges and the surface illuminates. Like fiber optics for hunting in low light. That big surface area is collecting all that light and concentrating it to the edges. Maybe try LED strips along all edges or reflective foil on the 3 other edges?
@Fl4ppers I was thinking the source video used 36 x 72 leds, after finding an astonishing voltage by our T&T😅 mate using just 20 on the short edge of the panel, while possibly adding a Fresnel panel collector front & or back panel. Thank T&T and You, and Merry Christmas lights to All.
Polar of spectrum is yellow, reverse of blue and wave-length is a wave and particle absorption and in series will add current and parallel will add volts when worked reversed...
The reason for the low voltage when LEDs are in series is that the LEDs only produce a fraction of a uA which is not enough to operate a meter even with its high input resistance. In parallel all the uA start to produce enough current to operate the meter. If you open a 2N3055 transistor the small 1mm square silicon can get as much as 2mA from the silicon which is thousands of times as much current. Solar cells from LEDs are not very efficient.
Please do more like this with LEDs / SMDs it's really fun stuff! Maybe see how many you need to power 1 LED fully and try different configs with capacitors etc. Keep it up mate
I've played with these. The colour of the light applied makes a change to the readable output. Blue light is higher than red light for example. I've always wondered if polarised/phased light makes a difference. I've been reading about growing plants and how they grow better if the microwave radiation is blocked. I wonder if the LEDS do the same. Thanks as always mate. Love seeing your stuff. Have a wonderful Christmas bro.
One of my favorite ideas of yours from past videos. Was considering adding a mirrored finish to the other edges, such as a mylar space blanket or aluminum foil, to increase the power generation, while minimizing the quantity of solar cells required.
One consideration I've found for reflectors on solar panels are heat spots. If the surface is highly reflective (like a space blanket) and it is not perfectly flat the light will become concentrated in areas which could cause degradation to the lifetime of the panel.
@@ThinkingandTinkering I'm not real familiar with that material, I haven't taken apart a computer screen for a long time. Was also thinking about the white paint that tech ingredients did, or the one that Nighthawkinlight did, but I think those convert light into thermal frequencies to radiate heat back out. Maybe a pure white latex paint would work, without generating the hotspots that @robrocker7 mentioned? The texture should distort any concentrations of light. Or white UV reflective paint. Someone has to have made that for a blacklight party.
I was thinking the same. Then I wondered if cutting a series of reticules into the side pieces would work better? Like a Fresnel lens angled to reflect the light up and down rather than side to side. Mirrors are highly reflective 98%+ and if the grooves are cut well they should have as similar level of refraction!
Interesting prototype, couple of ideas: 1. SMD LEDs may let you increase the light collecting surface area (packing more in a smaller space). 2. Could you control the refraction inside the light pipe to have different frequencies come out the the different sides and optimise the receiving "panel" for that frequency range?
personally i would try and find long thin solar cells - the main point here is the light guide - i suppose you could control the guide for frequency out put - interesting - cheers
@ThinkingandTinkering I got the impression you were targeting LEDs, guessing to to with the bandgap and the refractive index of the perspex. True solar panels are likely to be more effective yes.
@@andrewharpin6749 No mate i only used yellow LEDs because they are cheap, easy to get hold of and quite good if folks want to replicate and experiment with - but there are better alternatives - the main point of the video is the effect of the light guide
Using the coloured perspex demonstrates that the perspex redirects the same amount of light from it's sides as it does from the more concentrated end points, meaning that we could have solar electricity generating windows and even more solar light concentration for regular solar panels themselves possibly? Your videos are great and your continued work is appreciated, thank you, keep them coming :)
Polish and apply a mirror onto the other edges of the plexi! Maybe even just putting some aluminum foil or silver spraypaint along the edges that the LEDs are not occupying. I'd be curious to see how much of an improvement it makes. Thanks Robert!
One little tweak that could help is to somehow bond the LEDs to the edge of the acrylic with either a clear resin or Chloroform based Acrylic welding fluid, you may need to flatten the ends of the LEDs. It would be interesting to use and energy harvesting IC to charge a small battery or supercap, then at night have a PIR sensor to send the power back to the LEDS to create a nice light.
I think I'm going to have to try this with a bunch of SMD LEDs mounted to a few PCBs. But the best first step might be investigating the series behavior of the setup you've made.
The light guide was transparent, however I wanted to point out how reflective it was as well. I could see the chair across the table and a spray can in the reflective yellow. I wonder how much light it is blocking if so reflective. 3:04
And yet it's still better than the same LED strip without it. Might it be more efficient if it had a matte finish? Or would scattering the light be worse than reflecting it?
@brandonmack111 it's exactly my thoughts, matte finish. Thank you! Yes we are super smart 🧠. I was trying to think of ways to cut the gloss. The yellow works so well for being transparent and reflective it made me think and then I stopped thinking about it..
FYI, the reason why you got only a small voltage increase on the in-series strip is because *you are not illuminating all the LEDs equally.* It's important to understand that photovoltaic devices like this *are not voltage supplies, they are **_current_** supplies.* That means that you need to think about how they work in terms of the amount of current flow they produce (or allow), not voltage. If you only illuminate some of them, those LEDs will produce more current, but all of the other ones in series will not, so that extra current will not be able to flow anywhere, and will not result in any increase in voltage. It is only if _all_ of the LEDs are producing the same current that you will get more voltage/power out of a series-connected string like that. (Basically, the whole strip is limited by the lowest-producing member, so all of the darker LEDs in that string are "holding back" the lighter ones and preventing them from contributing any more to the total output.) (Also, keep in mind that phtovoltaics have a non-linear current-to-voltage relationship, which means that the amount of current (and power) you get out of them will depend on what voltage range they are allowed to operate at, which can also change depending on how much light they're getting. This is why most commercially-made solar setups employ things like MPPT (Maximum Power Point Tracking) controllers to try to get the best efficiency out of the solar panels at all times. Just measuring open-circuit voltage, or even voltage/current under a fixed load, doesn't necessarily tell you how much power you can actually potentially get out of different configurations).) Putting solar cells on the edges of fluorescent acrylic like this is actually not a new idea, and has been used in some types of commercial solar applications in the past, I believe. The main issue is that it is still nowhere near as efficient as just covering the whole plastic surface with solar cells would be, so it's really only useful in specific situations where you really need to be able to see through it, etc (and then you still have the issue that these sorts panels are still always going to be tinted, etc, to work, so it's not even like you get a clear window out of it or anything). More recent advancements in clear solar cell technology have made other ways to make things both more efficient and more transparent, which is why I think there is not as much interest in this sort of design anymore (commercially, at least)).
I'm sure you can really pack in the LEDs to boost the voltage much higher as well as placing them on all four sides. It's something worth looking into. I doubt people would want to look out yellow windows, though.
I first encountered this idea in the early '80s, promoted by a physicist James Odom. His idea was to use fluorescent perspex to down-shift light to wavelengths favored by silicon, and channel it via total internal reflection to the edges, as here.
I get higher series voltage by placing small capacitors in parallel with each led. My theory is that the capacitors serve as buffers for the electrons. When individual electrons emitted from individual LEDs can't force their way through the other LEDs, they accumulate in a capacitor instead of being lost. I like the idea of collecting and redirecting light with acrylic, but LEDs are very poor as photovoltaic cells. I'd like to see you try the same experiment with thin solar cells in place of the LEDs.
A very curious direction of thought, one that I myself have pondered at times. Light guides seem to address some of the unsightly presentations of solar power by condensing them into window frames and not block out the beauty of nature. All too many times advancement stifles nature.
In theory, if you glue or tape a mirror on the "back" side and mirror strips along the remaining three edges, there "should" be a slight increase in power output. Which also begs the question, could the blades of a wind generator be made from a similar variety of plexiglass ? That way, even if the wind dies down, it would still be generating some power. I think the vertical cupped or vaned wind turbines would be best.
I would think the lens architecture would have some affect. As for tree lights, I enjoy those flat top ones because they seem to shoot laser beams around the room. A 3m style led strip without weather proofing has no lens at all.
Bravo, sir. You truly are, in my mind, one of the greatest men of our age. I say this not just in relation to this video, but as a long time viewer. I found you many years ago when looking into graphene, and have seen much of your work since. May your name go down in history as one of the Greats.
The lower output on the series LEDs might be due to the D in LED. They might be acting as diodes and preventing current flow in the desired direction, or the voltage drop across the diodes might be adding, or they could be consuming power from their neighbors.
This is a very interesting effect. As said in other comments an optimized solar cell is far more efficient than an LED cell. This experiment is collecting light/energy from a considerable area. Savings can be made mirroring the edges of the Plexiglass. The real questions seems to be how much light energy is collected from the same area the Plexiglass presents to the sun compared to the same area of solar cells. The other matter will be the cost of this style of collector compared to solar cells and the area of light collection needed to collect say 1 Kilowatt of energy per hour.
very neat, thanks for sharing. I'm curious to see the data about the radious of deminishing returns IOT determin the best pane width before one would need to add another row of LEDs. I suppose one could build a sort of fibinachii spiral and by lighting the center the V could be measured along the outer edge to find out. I look forward to further videos on this very neat tech. !
Great video. I think that wired in series, LEDs will be limited by the greatest resistance in the circuit. Not like batteries at all. The panel might benefit from charging capacitors in series and discharging n parallel as you did in one of your prior videos.
Add mirror surfaces to the three exposed edges of the fluorescent panel to reflect back the escaping light. I'm not sure it would help or not, but it seems like it should.
Try the gallium arsenide green ones. They put off enough voltage to turn on a NPN transistor. You can make your own solid state relay that way. If I remember correctly they put off more than 1 volt 1.2 possibly.
So, this is the same for solar as the darwin collector for wind, collect a big chunk of input on a large surface and process it on a small device. I've seen a lot of very good suggestions on improving it with reflection. In this topic i would try to paint the back of the sheet with the brightest white paint possible as - instead of mirrors or foils - it would - if i am correct - filter out on the reflection stage unwanted frequencies (???) that interfere with those one, that are actually processed by the leds. On the other hand, what if we drill small concave "beds" where the leds contact the sheet? What i mean here is create small lenses on the sheet to focus the guided light towards the the leds.
I never thought of it that way but i think you are right it is kind of a Darwin for light - don't get tied up with the LEDs mate - the LEDs are a solar to electricity convertor - of which there are quite a few - what's important here is the light guide
Hi Robert. Your multimeter has a 10 MΩ or >10 GΩ selectable input impedance for 0.2 and 2V range. If you set it to 10G your series led's should match your expectations. I think 10V at least it can produce.
@@ThinkingandTinkering It worked ? I only later realised you can only measure up to 2V with that impedance. Any range above 2V will have 10M input impedance. Anyway, overrange for the 2V range is what you'll get. Does it ?
Yellow LEDs have an activation voltage of 2.1V Maybe with the LEDs in series, the voltage gets high enough to "activate" the LEDs & emit the energy back out as light. Might be able to see a very fast flicker with a high speed camera. You could try 2 or 3 LEDs in series & then in parallel to see if the results are consistent with your expectations, making sure to keep the total string voltage < 2.1
I worked on g-2 at Brookhaven on the position sensitive detector. The detecter was layers of optical fibers placed in rows perpendicular to each other. The fibers were doped with the same dyes as your sheet. When a muon beam passed through the fibers light woud be produced and you could make a rough map of the beam profile.
Once I took a strip of red LEDs, exposed it to bright sunlight, also got a minuscule increase in the voltage produced by the whole strip compared to individual LEDs in the strip. Never figured out why voltages do not add up. (Thought maybe the electronic voltmeter draws too much current, has low internal resistance, and drops overall voltage.) I also tried to connect one red LED to a series of LEDs, and power it up. Didn't work that either. Finally gave it up, but clearly it's a interesting question and requires a research.
I have a feeling for these as shutters of the american not german style, but I had a thought for future tests...aluminum foil backed, so that if they were open the light would shine, but they could close and have the foil "protect" things beneath them.
I have seen other playing with solar panels when one section is in shadow. Its output dropped similar to the weakest link. I suspect if you had a flashlight that hit all LEDs (in the series configuration) you would have seen a significant voltage increase.
Brilliant channel! How efficient are the LEDs in converting light to electrical power? What does voltage vs load resistance look like? Can a prism be used to separate sunlight into RGB then use colour LEDs to improve efficiency? Genuinely saddened to hear about your loss, and glad you're finding the inner strength to keep inspiring us to do better with the environment & CO2 reduction. This channel convinced me to think about and tinker with air-to-air heat pumps to stay warm in winter - and I have now switched off my gas forever... 👍
thank you for taking the time write and say that about Patti- I am impressed by you gas switch off mate - As for your other questions - i don't really know the answers this is early days - but you could give it a go too and see what happens
Have a thought Put the florescent around the perimeter of a glass window with the LEDs around the perimeter. You may get the same performance and have a clear window.
Would be interesting to know if you could put a "normal" solar cell behind the sheet, to collect the energy that goes "straight" through the sheet and does not bounce out to the sides.
Yes this works, but is quite inefficient compared to other forms of solar per metre squared. You could improve this with COB led strips instead (say 5 or 6 in parallel, as there are more LEDs over the same surface area compared to single diodes). Might also be an idea to experiment with lenses over the perspex. I wouldnt recommend doing too many in series as each diode can only take a small voltage, and exceeding that will burn them up. You always want the voltage and current to be under the diode array's tolerances.
I am sorry mate - you are guessing - COB doesn't work - but it doesn't really matter the main point of the video is the effect of the light guide - focus on that not the LEDs
Will you be testing the impact of the size of the acrylic panel? That is, does it take a large panel to boost the output, or can a narrower strip of plastic be just as effective?
that's a good idea - i always assumed it was an area thing - you make a good point - how ever I am unlikely to do that - just not enough time - you could try it though and let everyone know how it goes
Current solar panels are large area, computer chip quality (without all the millions transistors) and can't stand hail or other impacts. That panel is likely cheaper and easier to replace when damaged leaving the generator led/silicon along the edges where they can be protected better.
I would imagine the type of LED would make a big difference. Some are listed as bright, ckt board mounted, and different shapes. And we would have to check the different colors again against the different parameters of shape and sizes.
i only used yellow LEDs because they are cheap, easy to get hold of and quite good - but you are right there are better alternatives - the main point of the video is the effect of the light guide
I've heard that solar panels in partial shade produce almost no power for similar reasons to your series LEDs. A shaded cell is more like a break in the wire than a wire that's just not producing power.
I immediately wondered if pre drilled holes along the edge of the Perspex so the LED’s could ‘plug into’ the Perspex would have a better and less production and material intensive result.
Thank's it's a nice idea ! You can try with a optical fiber's to have a maximum of light on the leds with the good orentation of the light. So i understand it's not transparent. And i think you can use too a fresnel lens to concentrate more light on it. Can you try this ^^ ?
I think Oxford PV started with this idea that solar PV could be harvested from glass panels beyond the visible spectrum. Any materials with minimal visible impact but guide IR & UV to edge-mounted cells/diodes?
Nice video, do you remember the fibre optic lamps imagine 1 led per 1 fibre. Could be like artificial pampus grass in the garden. Maybe capture some motion energy aswell.
heres an idea, get the plexiglass the size of a picture frame, then put the led's mounted into the picture frame and all the wiring can be cut into the panel, but an additional wonder, will a reflective surface work for additional light into the plexiglass?
I guess this might be useful in an apocalypse if you live near an LED factory and all the proper Silicone or Perovskite panels were out of stock. As an experiment though, it is fascinating to see the effect of light guides and material absorption of EM spectrum... Not sure of practical use, might as well file under "interesting".
don't fixate on the LEDs mate - I only used them because they are easy to use and get hold of - the important thing is the light guide - imagine that with a standard solar cell
That's fascinating, but the best part was that laugh of pure joy when you found the whole idea a tally worked.
They have a transparent panel that apparently uses available IR and UV in daylight to generate electricity, while visible light passes through. They are using it mostly for greenhouses, if I am not mistaken, but this could be applied to house windows as well.
it was amazing when it worked lol - just cobbled together from everyday stuff - i love it when that works out
Yellow is interesting because IIRC photosynthesis operates off of red and blue. So this could lead to solar electric that does not interfere with agriculture, and greenhouses that produce both plants and electricity.
that is intereting and something i didn't know - thanks for sharing mate
It is good to see you posting again, sir. Thank you
cheers mate - thank you for taking the time to say that
Hi Robert. Good to see you back. Love the picture behind. Bless her. Keep going mate!
Thank you mate and bless you too - all the best
Acrylic can be bought in two ways. Light hits surface and directs out the edges, or the opposite where light enters the edges and the surface illuminates. Like fiber optics for hunting in low light.
That big surface area is collecting all that light and concentrating it to the edges.
Maybe try LED strips along all edges or reflective foil on the 3 other edges?
This whole design needs to maximise surface area to work its best. And it still wont compete with sand on price to metre squared.
@@Bloor005 sand??
@@joshuafoster8976 I think they just mean conventional photovoltaic panels made with silicon
I was thinking the stuff they put around the screens of laptops
@Fl4ppers I was thinking the source video used 36 x 72 leds, after finding an astonishing voltage by our T&T😅 mate using just 20 on the short edge of the panel, while possibly adding a Fresnel panel collector front & or back panel. Thank T&T and You, and Merry Christmas lights to All.
This is the first video I have seen from the channel and I am thoroughly impressed. Instant new subscriber. Can't wait to see what else is hidden here
I love how you explain things and how your genuine pleasure in what you do comes over in your videos. Thank you.
White is the worst because they have a phosphor layer in between. They use a blue or UV led that causes the phosphor to emit longer wavelengths.
cheers mate
@@ThinkingandTinkeringwhat if you use a clear panel and yellow LEDs (for windows that charge)?
I like to think of white LEDs as fluorescent LEDs.
Polar of spectrum is yellow, reverse of blue and wave-length is a wave and particle absorption and in series will add current and parallel will add volts when worked reversed...
The reason for the low voltage when LEDs are in series is that the LEDs only produce a fraction of a uA which is not enough to operate a meter even with its high input resistance. In parallel all the uA start to produce enough current to operate the meter. If you open a 2N3055 transistor the small 1mm square silicon can get as much as 2mA from the silicon which is thousands of times as much current. Solar cells from LEDs are not very efficient.
don't forget though mate this is not about LEDs - it's about the effect of the light guide
@@ThinkingandTinkering but trying to use what has just been said with the light guide might be an additional experiment, maybe?
Please do more like this with LEDs / SMDs it's really fun stuff! Maybe see how many you need to power 1 LED fully and try different configs with capacitors etc. Keep it up mate
You are a vision of intellect. Thank you for doing these.
wow - cheers mate
I've played with these. The colour of the light applied makes a change to the readable output. Blue light is higher than red light for example.
I've always wondered if polarised/phased light makes a difference. I've been reading about growing plants and how they grow better if the microwave radiation is blocked.
I wonder if the LEDS do the same.
Thanks as always mate. Love seeing your stuff. Have a wonderful Christmas bro.
cheers mate - thanks for the post and you have a great xmas too
A bloody brilliant and good man, that Robert!
cheers mate
One of my favorite ideas of yours from past videos. Was considering adding a mirrored finish to the other edges, such as a mylar space blanket or aluminum foil, to increase the power generation, while minimizing the quantity of solar cells required.
One consideration I've found for reflectors on solar panels are heat spots. If the surface is highly reflective (like a space blanket) and it is not perfectly flat the light will become concentrated in areas which could cause degradation to the lifetime of the panel.
what about that stuff they put around the acrylic of a computer screen? that should do a good job
@@ThinkingandTinkering I'm not real familiar with that material, I haven't taken apart a computer screen for a long time. Was also thinking about the white paint that tech ingredients did, or the one that Nighthawkinlight did, but I think those convert light into thermal frequencies to radiate heat back out. Maybe a pure white latex paint would work, without generating the hotspots that @robrocker7 mentioned? The texture should distort any concentrations of light. Or white UV reflective paint. Someone has to have made that for a blacklight party.
A brilliant idea, Robert! Happy Holidays...Merry Christmas🎄🎄
You look well sir, now to the point.
Experience of attempting a diy isolated solar light battery, gold is the most reflective.
Bright idea!
lol - i see what you did there lol - nice one mate
Simply illuminating!
lol - cheers mate
Great as usual! 👍
What about covering the 3 "unused" edges with mirrors?
Came here to make same suggestion.
Reflective aluminum tape.
On the back side of the panel as well would be worth testing.
I was thinking the same. Then I wondered if cutting a series of reticules into the side pieces would work better? Like a Fresnel lens angled to reflect the light up and down rather than side to side. Mirrors are highly reflective 98%+ and if the grooves are cut well they should have as similar level of refraction!
i was thinking the stuff they put around computer screens
@@ThinkingandTinkering Only one way to find out ;o)
Brilliant - merry Christmas Robert and family and thanks for all the fun and inspiration all year round. May 2025 be healthy and prosperous for you.
Thank you mate and merry xmas and a happy new year to you too
Interesting prototype, couple of ideas:
1. SMD LEDs may let you increase the light collecting surface area (packing more in a smaller space).
2. Could you control the refraction inside the light pipe to have different frequencies come out the the different sides and optimise the receiving "panel" for that frequency range?
personally i would try and find long thin solar cells - the main point here is the light guide - i suppose you could control the guide for frequency out put - interesting - cheers
@ThinkingandTinkering I got the impression you were targeting LEDs, guessing to to with the bandgap and the refractive index of the perspex.
True solar panels are likely to be more effective yes.
@@andrewharpin6749 No mate i only used yellow LEDs because they are cheap, easy to get hold of and quite good if folks want to replicate and experiment with - but there are better alternatives - the main point of the video is the effect of the light guide
@ThinkingandTinkering no problem, I read too much into it.
Have a good evening :)
Using the coloured perspex demonstrates that the perspex redirects the same amount of light from it's sides as it does from the more concentrated end points, meaning that we could have solar electricity generating windows and even more solar light concentration for regular solar panels themselves possibly? Your videos are great and your continued work is appreciated, thank you, keep them coming :)
Polish and apply a mirror onto the other edges of the plexi! Maybe even just putting some aluminum foil or silver spraypaint along the edges that the LEDs are not occupying. I'd be curious to see how much of an improvement it makes. Thanks Robert!
it might be worth looking at what it is they put around computer screens mate
@@ThinkingandTinkeringor coatings used on eye glasses lenses
thanks for your fun and engaging videos, Merry Christmas to you good sir!
Awesome, one of the best ideas, I'd say.
Wow, thanks!
This also should mitigate some of the issues with solar panels efficiency dropping when getting hot from the direct sun!
yes it would! - nice point mate
Years ago I was experimenting with LEDs in this way and the IR ones were the best.
cheers mate
One little tweak that could help is to somehow bond the LEDs to the edge of the acrylic with either a clear resin or Chloroform based Acrylic welding fluid, you may need to flatten the ends of the LEDs.
It would be interesting to use and energy harvesting IC to charge a small battery or supercap, then at night have a PIR sensor to send the power back to the LEDS to create a nice light.
A really great experiment. Bundling at the edges. Thanks Robert 👍💪✌
cheers mate
Top quality content right here. We have a whole avenue opened for technology to travel that wasn't there before
cheers mate
I think I'm going to have to try this with a bunch of SMD LEDs mounted to a few PCBs. But the best first step might be investigating the series behavior of the setup you've made.
I think you are right mate - to be honest i just glossed over that and right now i have no idea what's going on there - but well worth looking at
Enjoyed the experiment. Solar energy calculations should include the surface area used to gather X energy.
The light guide was transparent, however I wanted to point out how reflective it was as well. I could see the chair across the table and a spray can in the reflective yellow. I wonder how much light it is blocking if so reflective. 3:04
And yet it's still better than the same LED strip without it. Might it be more efficient if it had a matte finish? Or would scattering the light be worse than reflecting it?
@brandonmack111 it's exactly my thoughts, matte finish. Thank you! Yes we are super smart 🧠. I was trying to think of ways to cut the gloss. The yellow works so well for being transparent and reflective it made me think and then I stopped thinking about it..
with some materials you just have to accept the trade off mate - if you stop it reflecting it may stop it being transparent
@@ThinkingandTinkering have you tried UV ultraviolet light? 🙏
@@aaronbaca that is a good point mate - i haven't tried it but i will - cheers
FYI, the reason why you got only a small voltage increase on the in-series strip is because *you are not illuminating all the LEDs equally.* It's important to understand that photovoltaic devices like this *are not voltage supplies, they are **_current_** supplies.* That means that you need to think about how they work in terms of the amount of current flow they produce (or allow), not voltage. If you only illuminate some of them, those LEDs will produce more current, but all of the other ones in series will not, so that extra current will not be able to flow anywhere, and will not result in any increase in voltage. It is only if _all_ of the LEDs are producing the same current that you will get more voltage/power out of a series-connected string like that. (Basically, the whole strip is limited by the lowest-producing member, so all of the darker LEDs in that string are "holding back" the lighter ones and preventing them from contributing any more to the total output.)
(Also, keep in mind that phtovoltaics have a non-linear current-to-voltage relationship, which means that the amount of current (and power) you get out of them will depend on what voltage range they are allowed to operate at, which can also change depending on how much light they're getting. This is why most commercially-made solar setups employ things like MPPT (Maximum Power Point Tracking) controllers to try to get the best efficiency out of the solar panels at all times. Just measuring open-circuit voltage, or even voltage/current under a fixed load, doesn't necessarily tell you how much power you can actually potentially get out of different configurations).)
Putting solar cells on the edges of fluorescent acrylic like this is actually not a new idea, and has been used in some types of commercial solar applications in the past, I believe. The main issue is that it is still nowhere near as efficient as just covering the whole plastic surface with solar cells would be, so it's really only useful in specific situations where you really need to be able to see through it, etc (and then you still have the issue that these sorts panels are still always going to be tinted, etc, to work, so it's not even like you get a clear window out of it or anything). More recent advancements in clear solar cell technology have made other ways to make things both more efficient and more transparent, which is why I think there is not as much interest in this sort of design anymore (commercially, at least)).
I'm sure you can really pack in the LEDs to boost the voltage much higher as well as placing them on all four sides. It's something worth looking into. I doubt people would want to look out yellow windows, though.
Just the look of this is so cool. Like a 90's version of future tech, but it actually works.
lol - you are spot on there mate now you mention it it does remind me of 90s Sci-Fi
Man, I love this. Thanks for sharing your inspiration ✌️
Glad you enjoyed it!
Well explained and presented !
cheers mate
Awesome video. All your videos are amazing, thx u so much ❤
I first encountered this idea in the early '80s, promoted by a physicist James Odom. His idea was to use fluorescent perspex to down-shift light to wavelengths favored by silicon, and channel it via total internal reflection to the edges, as here.
I had a book light that was a plastic sheet like that with a light on the edge. Loved it.
they are cool
Looking forward to seeing what comes of this
me too
another unique expirement as usual ,it will come in handy .terry
cheers mate
I get higher series voltage by placing small capacitors in parallel with each led. My theory is that the capacitors serve as buffers for the electrons. When individual electrons emitted from individual LEDs can't force their way through the other LEDs, they accumulate in a capacitor instead of being lost.
I like the idea of collecting and redirecting light with acrylic, but LEDs are very poor as photovoltaic cells. I'd like to see you try the same experiment with thin solar cells in place of the LEDs.
nice tip on the caps - but you are right LEDs aren't the best - but they are available if anyone wants to experiment themselves
A very curious direction of thought, one that I myself have pondered at times. Light guides seem to address some of the unsightly presentations of solar power by condensing them into window frames and not block out the beauty of nature. All too many times advancement stifles nature.
for sure mate
Great work advancing DD technology's investigative insights
cheers mate
This is fantastic!
cheers mate
This is excellent. Looking likely that solar panels can give more. 👍❤️😇
I think so too
Awesome! 🎉
cheers mate
Thank you very much....
You are most welcome
In theory, if you glue or tape a mirror on the "back" side and mirror strips along the remaining three edges, there "should" be a slight increase in power output.
Which also begs the question, could the blades of a wind generator be made from a similar variety of plexiglass ?
That way, even if the wind dies down, it would still be generating some power.
I think the vertical cupped or vaned wind turbines would be best.
I think you are right mate - that would work
I was waiting for you to shine the light on the yellow plexiglass.
I would think the lens architecture would have some affect. As for tree lights, I enjoy those flat top ones because they seem to shoot laser beams around the room.
A 3m style led strip without weather proofing has no lens at all.
thanks for the heads up on that mate - i will try them
Interesting. Thanks for the video.
Bravo, sir. You truly are, in my mind, one of the greatest men of our age. I say this not just in relation to this video, but as a long time viewer. I found you many years ago when looking into graphene, and have seen much of your work since. May your name go down in history as one of the Greats.
LOL!!!!!!
The lower output on the series LEDs might be due to the D in LED. They might be acting as diodes and preventing current flow in the desired direction, or the voltage drop across the diodes might be adding, or they could be consuming power from their neighbors.
Condolences for Patti :(
Thank you for taking the time to say that - it really is well appreciated
This is a very interesting effect. As said in other comments an optimized solar cell is far more efficient than an LED cell. This experiment is collecting light/energy from a considerable area. Savings can be made mirroring the edges of the Plexiglass. The real questions seems to be how much light energy is collected from the same area the Plexiglass presents to the sun compared to the same area of solar cells. The other matter will be the cost of this style of collector compared to solar cells and the area of light collection needed to collect say 1 Kilowatt of energy per hour.
I don't know why people fixate on the LEDs - it's all about the light guide
I love this channel❤
cheers mate
happys seasons to you and all :)
And to you too mate - all the best
Merry Christmas
very neat, thanks for sharing. I'm curious to see the data about the radious of deminishing returns IOT determin the best pane width before one would need to add another row of LEDs. I suppose one could build a sort of fibinachii spiral and by lighting the center the V could be measured along the outer edge to find out. I look forward to further videos on this very neat tech. !
Great video. I think that wired in series, LEDs will be limited by the greatest resistance in the circuit. Not like batteries at all. The panel might benefit from charging capacitors in series and discharging n parallel as you did in one of your prior videos.
Great point!
Add mirror surfaces to the three exposed edges of the fluorescent panel to reflect back the escaping light.
I'm not sure it would help or not, but it seems like it should.
mate! this is fantastic.
Very interesting! You probably want to put a load on there, so you are measuring closed circuit voltage and current. Perhaps a 1K resistor?
I think you are right mate - cheers
Du hast Recht.
Wenn du Reihenschaltung machst, müssen alle LAD's auch die gleiche Beanspruchung erfahren.
Try the gallium arsenide green ones. They put off enough voltage to turn on a NPN transistor. You can make your own solid state relay that way. If I remember correctly they put off more than 1 volt 1.2 possibly.
So, this is the same for solar as the darwin collector for wind, collect a big chunk of input on a large surface and process it on a small device.
I've seen a lot of very good suggestions on improving it with reflection. In this topic i would try to paint the back of the sheet with the brightest white paint possible as - instead of mirrors or foils - it would - if i am correct - filter out on the reflection stage unwanted frequencies (???) that interfere with those one, that are actually processed by the leds.
On the other hand, what if we drill small concave "beds" where the leds contact the sheet? What i mean here is create small lenses on the sheet to focus the guided light towards the the leds.
I never thought of it that way but i think you are right it is kind of a Darwin for light - don't get tied up with the LEDs mate - the LEDs are a solar to electricity convertor - of which there are quite a few - what's important here is the light guide
@ThinkingandTinkering i guess making the sheet longer and comparing the outputs would give the answer
Hi Robert. Your multimeter has a 10 MΩ or >10 GΩ selectable input impedance for 0.2 and 2V range. If you set it to 10G your series led's should match your expectations. I think 10V at least it can produce.
brilliant mate - thank you for that
@@ThinkingandTinkering It worked ? I only later realised you can only measure up to 2V with that impedance. Any range above 2V will have 10M input impedance. Anyway, overrange for the 2V range is what you'll get. Does it ?
Yellow LEDs have an activation voltage of 2.1V
Maybe with the LEDs in series, the voltage gets high enough to "activate" the LEDs & emit the energy back out as light. Might be able to see a very fast flicker with a high speed camera.
You could try 2 or 3 LEDs in series & then in parallel to see if the results are consistent with your expectations, making sure to keep the total string voltage < 2.1
I worked on g-2 at Brookhaven on the position sensitive detector. The detecter was layers of optical fibers placed in rows perpendicular to each other. The fibers were doped with the same dyes as your sheet. When a muon beam passed through the fibers light woud be produced and you could make a rough map of the beam profile.
nice!
You should have a Maker fair and the trophy should be made out of recycled parts lol 😂 please keep TNT on
I like that idea!
Once I took a strip of red LEDs, exposed it to bright sunlight, also got a minuscule increase in the voltage produced by the whole strip compared to individual LEDs in the strip. Never figured out why voltages do not add up. (Thought maybe the electronic voltmeter draws too much current, has low internal resistance, and drops overall voltage.) I also tried to connect one red LED to a series of LEDs, and power it up. Didn't work that either. Finally gave it up, but clearly it's a interesting question and requires a research.
I have a feeling for these as shutters of the american not german style, but I had a thought for future tests...aluminum foil backed, so that if they were open the light would shine, but they could close and have the foil "protect" things beneath them.
Better would be the white plastic used behind laptop screens - However, remember it is meant to be see through
At last, a use for the led tapes I’ve been hoarding.
awesome lol
I have seen other playing with solar panels when one section is in shadow. Its output dropped similar to the weakest link.
I suspect if you had a flashlight that hit all LEDs (in the series configuration) you would have seen a significant voltage increase.
cheers mate
Brilliant channel! How efficient are the LEDs in converting light to electrical power? What does voltage vs load resistance look like? Can a prism be used to separate sunlight into RGB then use colour LEDs to improve efficiency?
Genuinely saddened to hear about your loss, and glad you're finding the inner strength to keep inspiring us to do better with the environment & CO2 reduction. This channel convinced me to think about and tinker with air-to-air heat pumps to stay warm in winter - and I have now switched off my gas forever... 👍
thank you for taking the time write and say that about Patti- I am impressed by you gas switch off mate - As for your other questions - i don't really know the answers this is early days - but you could give it a go too and see what happens
What do you think the stained glass windows are in old churches and cathedrals?
Behind the plate with fluorescent filler, a mirror should be placed to reuse the transmitted light by reflecting it back.
Better would be the white plastic used behind laptop screens
Have a thought
Put the florescent around the perimeter of a glass window with the LEDs around the perimeter. You may get the same performance and have a clear window.
cheers mate
Would be interesting to know if you could put a "normal" solar cell behind the sheet, to collect the energy that goes "straight" through the sheet and does not bounce out to the sides.
i love ur vids! keep posting
cheers mate
Yes this works, but is quite inefficient compared to other forms of solar per metre squared. You could improve this with COB led strips instead (say 5 or 6 in parallel, as there are more LEDs over the same surface area compared to single diodes). Might also be an idea to experiment with lenses over the perspex. I wouldnt recommend doing too many in series as each diode can only take a small voltage, and exceeding that will burn them up. You always want the voltage and current to be under the diode array's tolerances.
I am sorry mate - you are guessing - COB doesn't work - but it doesn't really matter the main point of the video is the effect of the light guide - focus on that not the LEDs
This concept has already been invented in 1977, and was used for wall clocks ('Fluko Solar') from 1987.
Will you be testing the impact of the size of the acrylic panel? That is, does it take a large panel to boost the output, or can a narrower strip of plastic be just as effective?
that's a good idea - i always assumed it was an area thing - you make a good point - how ever I am unlikely to do that - just not enough time - you could try it though and let everyone know how it goes
Current solar panels are large area, computer chip quality (without all the millions transistors) and can't stand hail or other impacts. That panel is likely cheaper and easier to replace when damaged leaving the generator led/silicon along the edges where they can be protected better.
nice point mate - cheers
I would imagine the type of LED would make a big difference. Some are listed as bright, ckt board mounted, and different shapes. And we would have to check the different colors again against the different parameters of shape and sizes.
i only used yellow LEDs because they are cheap, easy to get hold of and quite good - but you are right there are better alternatives - the main point of the video is the effect of the light guide
I've heard that solar panels in partial shade produce almost no power for similar reasons to your series LEDs. A shaded cell is more like a break in the wire than a wire that's just not producing power.
I immediately wondered if pre drilled holes along the edge of the Perspex so the LED’s could ‘plug into’ the Perspex would have a better and less production and material intensive result.
good idea cheers
Thank's it's a nice idea !
You can try with a optical fiber's to have a maximum of light on the leds with the good orentation of the light.
So i understand it's not transparent.
And i think you can use too a fresnel lens to concentrate more light on it.
Can you try this ^^ ?
I think Oxford PV started with this idea that solar PV could be harvested from glass panels beyond the visible spectrum. Any materials with minimal visible impact but guide IR & UV to edge-mounted cells/diodes?
Nice video, do you remember the fibre optic lamps imagine 1 led per 1 fibre. Could be like artificial pampus grass in the garden. Maybe capture some motion energy aswell.
i like that idea mate
GOOD JOB !!!
cheers mate
heres an idea, get the plexiglass the size of a picture frame, then put the led's mounted into the picture frame and all the wiring can be cut into the panel, but an additional wonder, will a reflective surface work for additional light into the plexiglass?
nice suggestion mate - cheers
You invented a window pane that can be put in buildings that will produce electricity
I guess this might be useful in an apocalypse if you live near an LED factory and all the proper Silicone or Perovskite panels were out of stock. As an experiment though, it is fascinating to see the effect of light guides and material absorption of EM spectrum... Not sure of practical use, might as well file under "interesting".
don't fixate on the LEDs mate - I only used them because they are easy to use and get hold of - the important thing is the light guide - imagine that with a standard solar cell
Each LEDs in series would have to generate a high enough voltage, so they beginn to conduct. With 0,3V this is not the case.
cheers mate
sometimes you just have to say - very cool
The difference in parallel and series is most likely internal resistance of the LED elements.
yes i thought that - nice to have someone agree