This thing is huge and bright. It runs at around 12V, but has no integrated current regulation. This means that if connected directly in a vehicle application the current could be very high and the voltage drop across the supply cable will be a factor in limiting the current.
The circuitry is basically four large parallel arrays of LEDs connected in series to make up roughly 12V combined forward voltage. I did some voltage/current tests as follows:-
10V 7mA 70mW
10.5V 170mA 1.8W
11V 790mA 8.7W
11.5V 1.72A 19.8W
12V 2.85A 34W
12.5V 4.2A 52W
12.8V 5.2A 66W Current Limit of bench supply.
As you can see form the voltage to current ratio the current increases significantly with a small voltage change.
A typical eBay search for this might be:-
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Sorry I am new to electronic fabrication, Is there a way to solder a connector to the board I would like to experiment with rigging 4 boards and I would not want to re-solder connections all the time. I am assuming that if the boards are wire serially I would need to provide n*12v where n is the number of panels linked in series.
I remember the first intensely blue and red LEDs of any worth coming out in the late 90's as cellphone antenna tip add ons...they were a fad for those early rich kid phones but inspired me to build my first LED growlight in 1997 for the low cost of $900 for the bright white, blue, and red plastic q tip sized LEDs found through research on Sierra Online...although my memory is a little fucked from all the high quality Cannabis I bred using that light and the 600 watt Gavita mirrored bulbs....ahhh the 90's
This looks like a really neat idea. Some vendors are now selling an impossibly small looking LED dimmer for this COB array that they say can handle up to 12A and deliver 244 watts(!) on 5-24V DC -- all for $2.75 delivered. Ooooookaaaaaay, lets see if it works. If it does the lamp should work well mounted on a homemade aluminum slide suspended underneath the top equipment shelf of my new electronics bench. Thanks, Clive!
If we can use these panels for video shots, we do not have to use LED strips to crate a panel. This is a panel ready for the job. We just need a dimmer, a power supply, etc. However, I could not find the CRI information on the product pages. Is there anyone who can inform us if these panels are suitable for video shots?..Will this panel give us good image quality? Please enlighten us.
These work VERY well used on a three-cell Lithium battery pack.
The full battery voltage is at the full drive voltage of the light.
Then, as the battery runs down, the light will gradually dim, giving you a handy indication that your battery's running low.
The LED cutoff is just above the safe minimum voltage of a 3-cell pack, so even if you set it and forget it, it shouldn't over-discharge.
Only complication is that you may need some way to cool the panel at full power/full charge, until the battery runs down a little. Fortunately though, you have 12v right there if you wanted to connect a fan and heat sink system ....
Fair enough. Still I guess it's the only way to see how things work, though, to be honest, I stopped taking things apart about 4 years ago as the art of putting them back together again, successfully I found almost impossible. Though I did manage to change my laptop processor on Monday, without too much damage. Thanks for the reply, Clive. I will definitely come to your next re-union if you can have it in Cheltenham. (Perhaps you could come for the races!)
My name is Lloyd Stovall I live in the u.s., I have some questions for you they're quite unusual because we are experimenting with different designs. Can you give me a call at 313-651-5349, I'm a talk so maybe you should find some time
@BIGCLIVE years ago i saw a simliar that scrolled with the name of what you desired to say thru inpur with a vga adapter what i was wondering is if it can be made big enough to say the words that were input ed example maybe 3 feet across 1 foot top to bottom , i have the original input device but not the screen can you or someone help with where to get it made already or design a simple one
Hey Clive, thanks for sacrificing your unit so we don't have to! Your videos are great!
I've bought 2x of these to make a large portable floodlight. I calculated that they draw about 5.8A (max) each and I want to power them both off a single rechargeable battery, for about 60-90 mins. So I assume I need about a 18-20Ah battery? Is that correct? Also, would it be safe to power the panels straight off the battery, or would I need some kind of current/voltage limiter - I noticed that you never took your panel up that high! (And if I do need to limit current/voltage what should I use?)... Many thanks in advance for your help! -Alasdair
Thumbs up for your videos! I really enjoy watching them.
I bought six smaller COB LED panels with each 50 watts to give my pepper plants a little boots of light for winter time.
But they heat up quite fast and i got about 70°C after 7 minutes with one of them mounted to a passive cpu cooling unit.
Could you make a video how to build a passive cooling unit for serveral of those in a row? I was thinking about some kind of aluminium plate.
I bought one of these cobs, but I have a driver that is constant voltage rated for a DC output of 12v +/- 5% and 6.2 amps. 72 watts basically.
Shouldn't this setup work, or will I end up burning out my cob?
I figured it would be alright because it can't draw more than 6.2 amps, but am not sure if I will be killing the panel or if it'll be alright.
Actually this array consists of twelve rows that each contain twenty-eight individual chips which makes for a total amount of 336 of em. Instead of twelve times twenty, which by the way would add up to 240 and definitely not 346 even though that number which in itself is quite close to the actual number counted correctly. IF this thing would consume 70 Watts indeed, that would mean a consumption of 70 / 336 = 0.208 Watts per chip , and when we would devide that by 3 as if we supposing
the applied voltage per individual LED would ideally be 3 Volts, that gives us a power consumption of 0.06ö4 (say 0.07 Amps or 70 MilliAmps per chip. And as each chip contains three individual, actual LEDs apiece, that gives us an outcome of 0.0231 A or 23 milliAmps per LED. There possibly is a few percents of that that are absorbed by wiring, a few micro components for voltage /surge protection and tp smoothen things out on the circuit and / or on the individual chips as well; taking that on account we still come up with a final actual power consumption that is close to a nice, round 20 milliAmps each LED gets. By the way, I do have a question about this: when the temperature inside the LEDs goes up, does the conductance and with that its own consumption as well as what it can pass through drop as a result? I am aware changes relating to temperate development in the LED /~ chip would need to be measured in nanoseconds. The way LEDs work is they get so hot the variety of individual metallic molecules (for composing the right part of the light spectrum) that are mounted on the tiny little pieces of silicon carrier in them, gets so hot that they start emitting light as a result, uv light which is passed through a layer of phosphorus to give out the right light colour. The LED works basically must like an incandescent light bulb did, but is much more efficient cause it only powers light producing molecules that lay directly on the surface all of which can emit light that can travel into (reach) the outside world ndeed, minimalising the losses in by molecules that are powered and produce loads of heat but are not in a position to bring forth light. Also the conduction is way more stable af sturdy, al the stuff being mounted on a plate that is surrounded by glass and encased / enclosed and it doesn't contain a wobbly filament that dangkes inside and can break by the slightest tremble. Apart from that some of the LEDs adjust to an output of the right (desired) visible light frequency by running the primarily created waved form of the photos it produces (uv) through a layer of phosphorus just like in the fluorescent light sources of the previous generation (tl) and the cathode ray tube in colour tvs (containing the separate photon sources scanning the inside of the tube creating the subpixels and three different types of phosphorus, one for each colour of 'dots' on the screen.. One for red, one for green, and one for the blue ones. It is what the modern ultra-flat LED tv for in common with the old one. Another thing, I do not know what the difference between power consumption and dissipation is, can somebody enlighten me.? Thanx !
It's just sad that people that know nothing about tech, even the manufactures of infomercial flashlights are so ignorant, that they can't even pronounce the name of the device. It is NOT a "cob L.E.D.", it is a C.O.B. L.E.D. Do you pronounce "U.S.A." as "usa (oosa)? Or I.B.M. as ibm (ibem)? Why would you be able to say "L.E.D." correctly (not lead), but not "C.O.B."? It is an acronym for Chip On Board, and it's pronounced "C. O. B.". It has nothing to do with a corn cob. I thought it was bad when that flashlight commercial was doing it, but come on, a lot of your videos are nice, and I was very surprised to hear you do that. lol, sorry, but it just sounds so wrong.
Clive... bought this right after your video was released. Could you please tell me how to make it chooch with a 12V car battery? Do I connect it directly or do I need some sort of a driver?? Links to that, please. DIMMABLE would be mandatory. It's 4 months now I have it, and haven't seen it lit yet. THANKS.
Thanks so much for your reply Clive. Sorry just saw it today. I set it up for a street-side fruit vendor's stall today, whom I'm helping out. It does not get hot at all on a 12V car battery. Will put in the 1 Ω resistor soon. So far it has run ok for an hour.
Thanks a million again.
For dimming you could use one of the 12V DC dimmers available on eBay or just use a series of switchable resistors. For running it from a car battery I'd suggest at least a 1 ohm resistor with a high power rating.
Just got one of these - amazing - running it with 4x18650's a 3A PWM controller ($2.00 ebay) and normal thin wires - it's blazing on full power, well worth getting!! Didn't bother with a heat sink - just glued the 4x18650 holder on the back of the panel - and glued the PWM on there also so it's one unit - super handy! There's enough room on the back of the panel for three 4x18650 holders (if u want longevity) and a PWM controller.
Ive purchased 4 of these already. And I've no idea what to do with them 🤣i put 14 volts throu a mini rf 12volt 19amp ( hah) controller and this thing gets so damn bright and the led was stable (as the led controller was smoking and melting down) the entire panel got hot as hell instantly, as opposed to previously on 12 volt 4 amps it took about an hour and a half to reach any type of temp like this. I don't know what kind of power I was putting to it when it got super bright and heated up the entire panel instantly. But I'm guessing you was closer to about 12 amps. Much higher than the rating. I can't find anything that's that powerful to push to this led. Ive burned throu all my controllers. I mean sure are you go online and spend like $80 on something good but i just bought a 12-volt 8 Amp power supply and the bastard only puts out 6 amps. 😒. Can't win for losing 🤣
bigclivedotcom im trying to think of a way to use a pelter thermo..whatever it is as a heatsink. Ive just now been seeing the 12volt ones on ebay for like 2 dollars. Is it the heat that shortens the LEDs life or the current?
So I bought a couple of these. As usual one of the sellers who sells everything and has no clue what they selling. They arrived in a simple plastic bag with zero padding and as they put the metal backings to each other, I assumed the worst. Although there are some marks in the yellow silicon, all LEDs are working (surprise, surprise). I had no problems soldering on a cable, set my Hakko to 800F and although the solder was sluggish it made good contact.
Powering them on I saw the same issue Clive saw with so many of the larger panels, LEDs are not matched. These are sold as 12V/70W, yet when applying 12V directly they only drew about 1.6A or just under 20W. So I wonder if they should actually run at a higher voltage than 12V, but I haven't found any other listing which doesn't list them at 12V. I am tempted to run them at a higher voltage to see ...
As said, soldering wasn't a problem. The cable lead I used is 18 or 20 AWG, it should not have a problem with the current. My bench power supply isn't good enough to drive much more (listed at 18V 3A, but cut out at 13.2V 3A). I am actually perfectly find running them at 12V 1.6A, they only got up to about 45C in a 15 minute run. Light output was good for the intended use as a table lamp (my wife wants bright lights for beading).
They do get shipped in a plain bag. I guess the thickness of the aluminium backplate is what saves them from mutilation in the post. For easy soldering to the panel heat the whole LED panel uop first. I put a clothes iron in a vice with the plate facing up and at a low setting to preheat the panel. If the current draw is low at 12V check the actual voltage at the panel connections. You may find there's a significant voltage drop across the cable.
I ordered eight of these at the beginning of the month, and they arrived today (here in Texastan). Two of the panels (the ones at the top of the stack) were all 100% uniform tested at 9.5V drawing 2 mA. Two had severe non-uniformity, and interestingly both tested drawing 3 mA. Four had mild to moderate non-uniformity, and all but one tested at 3 mA (the other was at 2 mA). one of the severely non-uniform ones has deep scrapes/scratches in the rear aluminum, the other severely non-uniform one had no issues with the backside. The ones I bought were wrapped in very thin foam sheets, and shoved in a plastic bag and mailed in the bag from China. I'm not sure if this is how they are all being shipped (I would hope not), but it is something that everyone might want to inquire about before purchasing. There was not even bubble wrap.
My numbers should be accurate, my Fluke 117 is NIST tracable.
I'm going to ask for money 3/4ths of my money back from the seller, or replacements that are 100% uniform. I'll update this with the results of that.
Oh, in an interesting coincidence, mine came from "valuedresshop" on ebay.
Has anybody an idea what kind of powersupply can be used for this panels. With a simple 12 V supply the panel draws only 2,85 A but only when it is cold. How much will the current rise when it is hot, maybe 60°C and it will rise a lot. To solve the problem we need a adjustable constant current supply with 12V and 5 to 6 A and the only way to get this is to use a 24V supply with an CC CV step down converter. This is to much effort and not efficient.
There are adjustable power supplies, but they're more expensive, and unless it's a space-sensitive application, I wouldn't want to drive these LEDs at anywhere near their full power. You don't want your LEDs getting hot, as it reduces their lifespan. It's easier and probably cheaper to just buy more of them and drive them at a lower current with a regular 12V brick.
I've been looking for a decent bench light for some time now. When you posted this I pulled the trigger and bought this because for the price you really can't go wrong. It came in today and I threw together a little mount for it and man is this thing bright! Here is a picture of it installed above my bench.
Not to bother you but youre the only youtube video woth this led cob... i heated it up like you said and it soldered perfectly. I attached a 12v 3amp ubec to it. On a 4s lipo battery it is bright and constant then it starts to strobe. -not flicker, but strobe. On a 3s lipo its dimmer but it doesnt strobe. When on 4s and it strobes i disconnect and reconnect the power quickly and the strobe starts as soon as i reconnect the power. But if i leave the ubec unpowered for a little bit it will not strobe instantly. I will get a few (maybe 10) seconds of constant light before it starts to strobe. I hear something about a led driver? But i thought a 12 volt 3 amp ubec would work perfectly. Would a small uf compacitor correct this problem? If so where would i put the compacitor at? Its so hard learning this stuff..
bigclivedotcom i bet that does have some play in itaftwr further experimenting. The 3s plays well because it doesnt over heat my 12volt ubec. My 4s makes it extremely hot. I also have 4 18650 batteries in series which is about the same as a 4s lipo (kind of i guess) the ubec about burned my fingers from the heat. I believe even hotter (maybe) than yhe 4s made it. But with the 18650 4s setup the strobing was extremely slow Compaired to the 4s lipo. Im at a loss. A larger ubec would probably solve the problem but then i risk blowing the leds from the amperage. The volts and watts and amps it specified online varied from listing to listing and i don't trust them. And on top of all that I'm a total noob. And im 31 😒 or 32.. sometimes i forget
These COBs act as a heatsink and cool the iron tip when you attempt to solder onto them. You have to preheat them before soldering. A common clothes iron or hotplate can work if set low enough to avoid damaging the LEDs.
Please, please, please do a video showing how to convert a par 64 fixture to led. We are typical poor, skint and broke musicians. We can all handle soldering irons and we can get the parts off eBay, but, we don’t know how to wire it together! Please help us Clive. You’re the only one who can! Thank you so much for your fantastic videos!
Really good LEDs at this point will actually dissipate more power in the form of radiant flux than they do in the form of heat, and this can kind of fool our senses. Something that is hot is going to have heat coming off of it if you put your hand near due mostly to convection. With LEDs like these however, most of the heat you feel is actually from the photons impinging on your hand, not because the actual source of the light is hot. It still messes with me, because it feels just like putting my hand near something quite hot, but if I cut power, the heat vanishes, and the COB will be much cooler to the touch than something that could ever have produced the heat I felt on my hand via convection.
The newest blue-to-violet LEDs as of 2018 (which are used to make white LEDs of course) have an efficiency of about 72%. Put in 1W of electrical power, and get out 720mW of light, along with 280mW of heat. You can buy them on mouser, digikey, etc, this isn't something in a lab. They're so good they seem almost unphysical.
When you popped that poor inoffensive LED, all I could think was NOOOOOOOOOOOOooooooo! I'm glad we have a ruthless hitman to do the deed. Like buying meat at the supermarket, get someone else to take the hit and then take the spoils in a nice clean package.
Agree with twocvbloke, the tech is moving at a fearsome rate. candles lasted for 100s of years, Incandescents 1880 (ish). CFLs appeared 2000(ish) developed to a usable source and then have virtually vanished by 2017. LEDs (as a domestic light source) are changing almost daily if you have the time to trawl e-bay.
Thing I'd like to see now is a safe way to power the damn things so you can be reasonably confident they won't bite back.
Clive I have just purchased this cob for a photographic/video project in cool white. Could and would this run on an ac/dc 12V 80W output driver (as that’s what I have chosen to drive it with)? I have an huge industrial laser cutter heat sink to mount it to. Best regards Phil Steadman
Before watching - those wires look awfully tiny to pass 5A+ through them to feed this beast. Sure, they're thick enough as to not get too hot and melt under such a current but one has to account for bending and things like that.
Trading stocks typically have the lowest fees on eToro, which is one reason why I recommend you stick to this market when starting out.
All trades charge both a spread and daily rollover fees.
It really comes down to individual trading strategies and preference. But to give you an idea, I tend to hold on to stocks for a minimum of 6 months and all other trades tend to have an average duration of about two-three weeks.
A final word on over-trading.
This is a point that I want to expand on a little more, specifically in relation to copying other traders. Below is a screenshot of my equity chart over six months. The red line shows the number of people copying me.
My equity vs copiers chart.
The same holds true for the stock market in general.
Long-term growth of UK stock market.
How to Start Trading Cryptocurrencies.
Cryptocurrency trading can be extremely profitable if you know what you are doing, but it can also lead to disaster. Even though most traders decide to either go with fiat or bitcoin, other cryptocurrencies can represent viable income sources, as long you as you tread carefully and understand what you are doing. This guide is for those who want to start getting involved in cryptocurrency trading.
Where to trade.