The continuing story of crappy high power LEDs.
ฝัง
- เผยแพร่เมื่อ 30 ก.ย. 2016
- Yet another crappy high power LED from a shady eBay seller finds its way into one of my bench lights. This time it's the turn of what I can only describe as a fake 50W LED that walks the walk, but most certainly doesn't talk the talk. It does have the correct appearance of a 50W LED, but the 50 LED chips arranged in the traditional five rows of ten appear to be very small. Probably the smallest LED chips I've seen in one of these LED arrays, and suspiciously small enough to make me think they may be common chips used in 5mm LEDs. The backplate of the LED is also unusually thin and the weight of the entire LED module is around a THIRD of a typical high power LED. It just feels light and flimsy. The connection plates are unusually rotated at 90 degrees to normal, but the base does align with the standard mounting holes.
The output is a bit "grey" in that it has a blue bias and is visibly dimmer than the LED in the other fixture. (A dodgy 100W one with leaky chips that is being run at 20W.)
I think I may be changing this LED soon.... Even if just to get the intensity back up and a better shade of white.
If you enjoy these videos you can help support the channel with a dollar for coffee, cookies and random gadgets for disassembly at:-
www.bigclive.com/coffee.htm - วิทยาศาสตร์และเทคโนโลยี
![[HIGHLIGHT] หมีLIVEปะ? | EP.171 เห็นแต่ในจอ วันนี้มาต้องขอคารวะ](http://i.ytimg.com/vi/gPWLxa0e_Z8/mqdefault.jpg)
Chanzon LED store on Aliexpress has reasonably priced good LEDs. About $7 for 100W.
I do like a bit of L707, one of my favourite colours. Really makes reds pop out, used it to light a band with lots of red guitar leads once...
I love Lee filters. I had a box of 32 sample numeric edition swatch books which they sent me and worked my way through them slowly over the years. They work brilliantly inside flash filters.
I've got one of those outdoor PIR LED lights you reviewed last year. It still seems to give out enough light, despite being through a full cycle of crappy British weather.
I'm really enjoying the saga!
I wonder if the ebay cheapies are discarded stock that some guy is recycling?
factory rejects that go to cheap led applications
Someone dumpster diving behind the LED factory...
Neffers
F
I actually talked to a Chinese seller ( that produces good leds) and he told me that the ones who are discarded go on sale on ebay..
And the good ones will be sold on the market..
Andrew van Leeuwen
Baaaa-stards! >:(
As always Clive,, good job, keep up the good work. ..
I have replaced the 4 foot florescent tubes, with 15 m of double row led strip lights. In a bathroom where I had to replace the florescent tubes every year. After 4 years the leds are still going strong.
Here we have to pay to dispose of the florescent tubes.
The bottom line that our older male sibling tells us, is not always true....
Great video Clive. Keep up the great work. Nick.
I love those LEE swatch books. I have several at home. Some are destroyed as I've used them for torches!
Clive, there is a seller on eBay I'd like you to check out. I saw a video from another TH-camr who mentions this seller. All accounts of the high power LEDs from this seller are good ones. They are of a different design than the ones you typically deal with on your channel. They have properly matched LEDs that all light evenly, and they have (supposedly) eliminated that gold wire bonding separation issue you have encountered. The seller is cici-led-lighting. I'm ordering some myself.
feedback.ebay.com/ws/eBayISAPI.dll?ViewFeedback2&userid=cici-led-lighting&myworld=true&items=25&iid=-1&de=off&which=negative&interval=365
I wondered why my local council had installed gas discharge street lights. As I thought LED was better, but obviously not. As you said a local utility company, had no end of problems with there led street lights.
hi bigclive
another excellent video
keep up the excellent work
The earliest version of your supercomputer! - There must be some ZEN going on here!!
I think I have that swatch book somewhere.. loved it to bits ;)
I think I made this comment on another video, I swear we (Big Clive) would have made bbf's as kids. I used to take every toy, TV, VCR and other electronics apart. It got so bad I stopped getting anything that needed a battery and given heavy die cast toys. The consumer electronics were either broken or beyond use, only issue was as a 4/5 year old I didn't know when to stop. I remember the time I took the brand new Sony triton TV apart, so many shocks from the brightly colored caps
I like that kinda neutral coldish white, looks good on the desk, not are much bloom or glare either, a more accurate light.
Talking about street LED stuff, my closest town has had a few RGB colour changing lamps around a water feature for a couple of years tops, and they no longer fade between colours, all they do is flicker once in a blue moon when there's a spike in a given colour range. I was bored and sat and watched them for ages while waiting for a bus. It was a bit like your strobing LED scenario but way less frequent.
Been running my Cree XMLs for years without issue. I'm guessing the issue you note is specific to the yellow cluster LEDs. There is a definite appearance to them of beong built to a lower standard, especially if so many aren't lighting properly. Sounds like major QC issues.
My use of LEDs beyond simple indicators has not progressed terribly far to date. I have some that I purchased from Banggood that were allegedly 10W units, and am running them at about 3W and the one in front of me is doing quite a nice job of lighting up my desk. I have it attached, along with the little electronics module, and a "DC" connector, to a bit of aluminum salvaged out of some TV or monitor and shaped to my purposes. Not a real heatsink, but one isn't needed, and after this one has been on for *many* hours it's barely warm at all. My feelings about what I was seeing when I bought these a while back was that the higher-power units gave more opportunity for ending up with something dodgy, and I really didn't want to bother with 1W or 3W units at that point in time. If need be, I can put together an array of these things on a bit of aluminum angle or something, but so far I haven't seen the need. Somehow I have the feeling that if I'd gone for 20W, 50W, or 100W I'd end up playing the same sort of game you're playing now, and I really don't want to.
Taking the Kelpie by the Bridle... Good Video Clive :)
I've just given up on these, am settling for arrays of Cree 3W, 5W, 10W, then arranged in series to work with the cheap ebay drivers in the config I want. It costs a couple bucks more, requires a few more screws and solder joints to wire it up, but the reliability is higher, heatsinking easier too since a higher efficiency without leakage current, and should an LED fail later then you only replace that one, plus you can pick a mix of color temperatures to arrive at what you want, or higher CRI.
I've got 10x 100W modules set up on an aluminium bar (with proper heatsinking), hanging above my engine bay in the garage. It's a great help for working on cars.
They were the cheapest ones I could find on AliExpress. I didn't expect much, but they have chugged along perfectly, being used about 10 hours a week for the last year. I have been running the snot out of them, 100% power. No rest for the wicked.
I supposed not all cheap things are nasty, hey?
I devised a saturable reactor type regulator for them. Non-isolated, straight off the mains - not for the faint hearted I suppose. But very simple, tough, effective and can be made from junk. Perhaps I should do a video about it?
i wonder, would you do a video on the lighting fixtures these are designed for?
I really want you to show some test on Cree's led chips, would like to see if they are good quality
Could you kluge a way to clamp the one side to get the mostly good one working?
Congo Blue, ....that'll be Lee 181 then. Can you tell what I do for a living?!
Those failing ones might make for interesting art displays... especially if you have a way to add/remove pressure on the bond wire ends to make segments light randomly
I was in drama club in highschool and our teacher taught us how to make our own gels to save the school money was a neat process but a pain
The moment the video started my first thought was "Hmm, is that congo blue?" I knew i could trust you to answer my question soon enough : )
Watching bigclive wants me to build some LED lighting for my desk as ambient backlight, i wonder how cheap you can make it.
wow! I used to work for Lee filters a long time ago good god the solvent abuse in there was just part of your everyday working life......
should test the cree led headlight kits!
Great video
I've bought a 100W one from banggood and it hasn't shown any asymmetrical illumination on low current
I got cheap 100w chips, from few different sellers on ebay, and received few that all chips light up at lower voltages, still have no problems with them but i changed few drivers (actually step up converters)
Hmm, if thermal expansion is the main failure mode, then perhaps avoiding the dimensional link to a PCB substrate would be a solution. As in mounting the chips on a loose mesh of copper wires whose internal distances are entirely determined by the chips themselves.
The 100w ones were always a bad idea. As for the local council, my guess is they will be paying out a lot to return their streets to HPS or SON.
The question is though... What's the one in the bag?
A 20W LED that was removed, but is still in good working order. the bag was to stop the heatsink compound getting everywhere.
m
Thank you , nice demo I just bought two Ebay 50 watt floods for $20 w/case so i'm sure they are NOT going to be what I expected , have you seen or tested anything from Ebay that shoes any improvement since this video was posted ?
Thanks again Nice job
The council is putting LED street lamps in my area, it looks like the fools have chosen a cold white.
I'm wondering what repercussions light temperature may have on the environment not being that soft glow.
cold white is more lumens per watt, the real issue is, they are narrower beam, too narrow, and even inthe beam it seems to be much less light
They outfitted a street in my city with cold white LEDs. It feels almost like you're walking through a big box retail store with how 'aggressive' the lighting is.
A long section of street in my area had its traffic signals replaced with LEDs. I truly hate driving there late at night - it's so bright it disrupts my night vision. BUT... I bet it looks absolutely fine on the city's spreadsheet.
The sharp beam cutoff is mostly due to fixture design. A proper LED array will have individual emitters pointing at various angles with a diffused lens. Many LED arrays used in streetlamp applications just have a bunch of emitters on a flat plane pointing straight down, with each emitter having its own tiny reflector.
spikester
they will want to fool the lightmeter, so all the light will be at one spot, then they can claim oh its the same light output, see the meter readings!
I've found a source of very cheap but seemingly good cobs. The 100W DC-LE14162 (yes a china chip with a model number and certificate of conformity!) lights very evenly at low lux and has a maximum operating temperature of only 55c (for long life i guess). I look out for the photos on a popular internet auctions site showing this low lux evenly lit state then delve deeper to find the model number/s. Cheapest i find are about £1.60 each. Theyre quite weighty too at around 19g. One of the listings found has a full range of ratings and colours, all as cheap as chips (pardon the pun) :)
Are your LEDs mounted above your desk in some of those work lights that you've done teardowns of on your channel? Or is the setup a little more DIY?
Proper 20W floodlights.
I prefer Parma Violet, personally :P
Are those sample filters free samples? I had a look on their site, but couldn't find it :(
probably not, same with fabric and carpet etc sample books.
Azayles shop.leefiltersusa.com/Swatch-Book-Designers-Edition-SWB.htm they have a special going at the moment
Leigh Bucksey Damn, I leapt on that offer, but it looks like they only ship within the US :(
Thank you though :)
Azayles also have the here m.stage-electrics.co.uk/shop/sales/lighting/colour-filter-and-gel/colour-swatches/product.aspx?code=558-9029 free for the product just have to pay shipping
Leigh Bucksey You beautifully kind and helpful man :D Thank you so much! :)
Left side of the video looks a little bit more purple to me. Though that's probably just what the white balance of the iPad makes of the lights combination?
LEE Filters...oh I still remember several filter names an numbers :)
Would love to know where my swatch book went, not that I would use it now, it was older than your one Clive, it was Rank Strand!
Does this still apply to the 3w chip cobs?? I have 6 x 32, 3w chip fullspectrum cobs in the one shell and they say they are drawing about 48 watts of actual power each 32 x 3w cob
Frankly, Clive, I'm surprised that you refer to yourself as a cheapskate what with your love of all things Poundland, not to mention your Banggood purchases! 😉
However, we all love a bargain, don't we?
Clive, what do you make of the LED tapes available on eBay and such like? DIY Perks has done a few projects with them. What are they like for longevity?
It's very random, but I've been using some cheap warm white LED tape in my kitchen for a long time now and it's not got a single LED out. As an extra layer of insurance you can add a diode or two in series with each section to drop about half a volt, which will translate to a slight drop in current through the LEDs making them last longer.
The fascinating thing to me is that all these cheapo no-name COB LED modules have roughly the same design -- a different design from the (more expensive, but good) name-brand stuff (Cree, Bridgelux, Philips) you'd get from the usual legit component suppliers. (That said, the good ones are expensive enough I'd tended to play with my driver design using a crude zener + power NPN load first.)
I'll stick with my 2x 4' T5 28w fixture above my bench complete with dimmable high frequency driver/ballast.
I'm surprised you don't have something similar for filming purposes to be honest! You can get 90+ CRI tubes relatively cheap (circa £6 each) and the dimmable driver is a quality brand (Tridonic) and cost £8 brand new off ebay!
have you bought any from Lohas LED? i have only gotten good chips from them, i have a 100w in a small flashlight that i use all the time, and its adjusted with a potentiometer from 0 to about 66 watts, and at any setting every single chip inside is perfectly evenly lit
I see so many of these bad LED modules, I have to wonder if the automotive industry has eaten up all the good ones!
I think the best modules go to the street lighting, warehouse lighting and other lucrative industries.
LED quality seems to be a constant problem. Where I work, we had, at great expense, a lot of LED floodlights installed. They all worked perfectly. For a week or so, then they started dying off. They were replaced - same story. We had to have them, as a security measure, but within months, they had all died. They were replaced with ordinary bright spots. No trouble whatsoever. I asked the duty sparks when he was replacing the LED clusters what the problem was. "Easy" he said, sagely. "These are fuckin' shit."
does Cree make threse style of LED panels ?
we just had led street lights, they are much narrower (some of that is good, less light pollution) but the light output is about 1/5 of the old sodium, the blue colour i might get used to, but the lack of light, not so great
Same here for some of the lights. Just small patches of light directly below the street lights to cheat the intensity readings.
That's just cheapness. LEDs are superior, when you pay for them. I don't know why people bother with these cheap Chinese square LEDs and then cry when they test them and are crap. As a hobbyist, I wouldn't even touch them. They don't even look like they are even made for a company with a real name.
Where I live, they replaced the few low pressure sodium lights we had with narrow beam LED lights.
They're great if you're under them, but everything between them is pitch black. Brilliant if you're a pedestrian (sarc).
I'll go out sometime and check it, but I don't remember that we have these problems. Or maybe the sodium based lamps were crappy. The fancier street light are kind of designed to well diffuse the light, the higher, more powered lamps are not, but I don't remember that they have these problems. Only problem is fog, because it makes the fog more foggy, but thats the cost of the white color.
The more narrow beam is good for light pollution but the blue frequencies reflect more in the atmosphere and contribute more to light pollution.
Ahh these comments
They've got these on Amazon and from what I can tell they're actually decent.
I received yesterday 2- 50 Watt LED's from E-Bay and was hoping for the best. Tested them and found out that one had 14 working 1 Watt LED's, the other 13.
It is apparent that these are discarded items and sold as scrape by the manufacture.
We used to machine automobile cylinderheads. Not a huge quantity - maybe 100/month (it varied). And over time, many would accumulate in the 'defect' bin.
Every so often we would have local 'businessmen' come by and pick which they wanted - at a very low price. They did whatever they did with them - treating the problems however they saw fit and reselling them.
The gist is, we were able to recoup some of the loss this way.
I'm certain the same thing happens in China's manufacturing industries.
With LEDs, I'm sure there are thousands of these 'less-than-optimal-quality' units being sold, as-is, to less-reputable businessmen.
can you re-flow the good one that has bond failure
No. It's a gold bond wire welded to a busbar and covered in phosphor loaded gel.
could you apply solder iron to the led that has wires separating and possibly save it?
Well it is all potted together so your would need to tear it down first, and the LEDs wouldn't survive that anyway.
The best attempt would be a mounting bracket that clamps down right on the ends.
I was thinking a bit of glass held on with clapton tape.
What do you think about the proposed dangers of blue light (eg from mobile devices, computers and LEDs)? Do you know of any effective filters?
I think the main issue with sleep loss due to "blue light" is actually people watching TH-cam until 4am.
both apple and amazon tablets now support some orangey night time option, makes everything tangoed, can barely read it, so you give up and go to sleep instead of playing with it half the night.
It's useful and informative to see this - perhaps a step further?
Out of the 35K viewers there must be a few folk who can volunteer better suppliers? - it might even nettle the skip diving sellers to up their game - howzabout a league table of the the good, the bad and the downright ugly?
Several 'tubers list the provenance of kit.... I know from visiting Shenzen that the suppliers *will* pay attention. :-)
If you want to ensure you are getting an LED rated at the value you requested where should you buy from? Also have you come across any good high CPI LEDs from a cheap supplier?
It would be interesting to look at light output decline over time. I have been using several home made 1.5m long LED strips for general workshop lighting for almost 2 years. I'm sure the light output is declining but it happens slowly and is hard to tell. These are just cheap LED strip stuck to alloy angle running off a power supply and dimmer. A few LEDs have failed and some seem to be slowly changing colour.
Several years ago I used to repair LED traffic lanterns; all standard 5mm LEDs. One brand is terrible for green failures. The flickering and gaps are obvious when driving past. Once a number have failed the lantern refuses to operate. I think they are a bit cheaper now and just get dumped. replacing the special green LEDs is far too expensive.
LEDs do degrade visibly with time, especially when run at full current. It's worth treating the LEd strip as a disposable item and just buying new stuff every so often. Also consider adding a diode in series to nudge the voltage and current down.
What're your views on Rosco gels Clive? I've always found Lee to be superior, but worked with some LDs that swear by them.
Is there any reason why they put the effort into connecting dozens of tiny chips together, rather than just making significantly bigger chips? Obviously more silicon area means higher cost, but I'd have thought maybe a few giant chips would be better than tons of minuscule ones.
I have 5x20 watt led lights in my workshop and after a short time I had to replace all of them with new, they started to flash, I striped them down and found that there was small burn marks on the leds also none of the led fitting had the earth wire attached. Crappy lights.
If the main cause of failure is mechanical - thinking laterally ... how about sandwiching the LEDs by clamping a flat transparent lens over the chips to keep them pressed in place?
The extra heat could be the biggest problem, but a sink on the back with a bit of thermal paste, possibly even assisted by a small fan. Shouldn't increase the size of the lamp too much.
I kinda like left side of the video more
Bad news, I swapped that LED to match the right side. It was just too "grey".
Indeed. The chip on the left seems to have better R9 rendering.
Could these failed bonds be fixed with heat (e.g. a reflow oven)? Or would you end up with a sticky, gooey, smelly mess?
But if all the chips light up within their specified voltage... then what's the problem?
The main issue is improper design - semiconductors are notoriously hard to put in parallel, specifically some diodes and MOS transistors. This is because they can "hog" current as the heat up, which causes them to heat up even more, until the device overheats and fails. This is why it is VERY important to make sure the LEDs are all balanced if you have them in parallel.
Hi,
Did you notice that the polarity marking ( + & - ) on them are not in the terminal side? I have some and they are 90 Degrees off. they are on the no connection sides !!
That's because the ends of the diode rows are connected in that polarity. I think the original idea was that the wires came through the two extra holes in that area and soldered onto the recessed metal tabs next to the polarity markings.
The new 10w chips are absolute crap compared with what I used to get. The only up side is that they work better with 12v power supplies. ( Being 12v nominal, and 14+ actual ) But even still, I prefer the old ones with higher efficiency. I used to use the cable as an inline.... (Use undersized cable to add a couple of ohms) .
Any of those are destined to fail, no even taking into account bad bonding.
Chips are connected in series and then paralleled - as LEDs age forward voltage changes, and eventually single strand will hog more current, heat up, current will rise up even more due to falling forward voltage, strand goes out due to overheating, cue next strand.
I'm not even sure why the don't use a resistor in there to improve current sharing...
Where do you get quality LEDs?
You can get some good LEDs from DigiKey, but they don't come cheap. They are much more efficient than the cheap ones though.
Any idea what the flash is that occurs just before you attach the power to the LED @4:52? Seems rather odd.
I didn't even notice that. I wouldn't even say that static is a significant issue at my bench. Very odd.
the whole array of chips lit up, that current had to come from somewhere so he must have just brushed the edge of the contact with the tip of the crocodile clip before actually attaching it
Where did you get the Lee Filters from? Link possibly? Thanks! Don't stop making videos or I'll actually have to go outside for once
If you have a local theatre supply company or film lighting company they may have a modest stock of gels.
"I don't want to spend 30 quid on one LED" he said, sitting on a pile of 50 1-quid LEDs that failed
I would simply avoid any leds that are in parallel I love the 10w 9 in series they are usually reliable and only 20% more expensive than the 3 series 3 parallel
I've been using a cree CXA series cob led array run at 40w as a room light for the past 2+ years, the middle strip of leds failed around 6 months ago but i'd put that down to my piss poor thermal design over the quality of the led. i'm leary using the weight of them as any indication of quality because name brand arrays usually are very thin and weigh only a few grams being just the leds inside some type of polymer with phosphor backing on a ceramic substrate instead of huge chunks of plastic(?) and some type of metal with honking leads. seems like little consideration was taken for thermal expansion coefficient differences so they just rip their own bond wires off after a thousand power cycles killing them way before the diodes themselves could ever have a chance to fail.
are there any good namebrand LEDs?
I prefer to use individual 5mm LEDs. No heatsink required and cheaper and easier to replace if they fail.
I got one of these 100W LED's
got the pure white option of color temperature
its got huge LED chips which are so huge there's only half or quarter the size of the chips amount of space between each LED chip
they look massive in the photo
they also have two gold wires going to each LED chip and they dont look spotty or dodgy at all even in the photograph
Was 10 dollars on amazon for me.
then where do you get a good led like this that isn't 80 quid?
Over the course of buying the cheaper ones, would it have cost more than 30 quid? It would be interesting to do a long life test with a 30 quid one vs the cheaper ones and see how long they last.
The cheaper ones are much more interesting to see how they behave and fail.
How about the 10w LED's from Banggood? Are they bad also?
I've not had so many issues with 10W LEDs. They seem to be much more consistent.
Would it be possible to reflow the LED's with bad bonds on the sides? Or are they attached in a specific way? I was just wondering if you could simply fix it with your heat gun (I guess not).
They're attached with the equivalent of a microscopic precision spot welder.
Thanks for the reply. I don't think I'll ever not be fascinated with the fact that they can automate a process like that on such a tiny scale. Would love an episode of "how it's made" on LED's or other electronic components.
FWIW, I bought a bunch of 100w chips from a seller in the US called due20150801 recently. So far, none of them have had any dead LEDs in them.
Recently, my first "brand name" LED died. It was one from German electronics vendor "Conrad Elektronik", and the "brand name" of it was "Sygonix". It lasted about 3 years, but never the claimed 50,000 hours nor the 15,000 switching operations. Then I tried to open it, and it was almost impossible. I had to destroy it, just in order to find out that the whole circuit board was sealed in some sort of rubbery plastic goo, and there was no way to fix it.
So I can only tell everyone: Never, ever buy a LED by "Sygonix", because these things are just as crappy as the worst chinese LEDs, but cost much more than those.
what powered it?
Sirus What do you mean? It was powered by electricity...what else? ;)
But I could add that it was an E27 retrofit LED with a giant aluminium heat sink (almost 2/3 of the length of the "bulb" were heat sink, and inside was the PCB in another aluminium tuebe), so it was powered by 230V as we have here.
Seegal Galguntijak
Amazing. Was the power supply good and clean? I'm sure you will tell me next that it was shiny.
So, if the bonds on the LEDs broke could you do the ol' magic trick of putting them in the oven?
No. Sadly it's not solder bonds, but tiny welds.
bigclivedotcom Ah. That's too bad. I've had to do that with a few boards on some older HP printers. Sometimes it will fix the tiny beading on chips.
How long do these style of led lights last on average?
It depends on quality of manufacture and the environment it is used in as heat kills LEDs. The current ones are not that great.
Are the led banks wired in series or parallel ?
Yes.
Clive, what bench psu do you use?
It's really dodgy slimline Maplin one that seems good, but has a very odd (but common) quirk where it can crash once every so often and put out a random voltage. Hence why I never really mention it as I wouldn't recommend it.
2:32 Well screw you too! LOL
Given the little sampler there, could you not tone down the coolness of the cool-white LED with some theatrical gels? I'm going to try just that with my shed lighting, though having tried a sheet of "103 Straw" I got on a cool white LED filament bulb, I don't think it's the right shade, could do with that sampler, having been an amateur lighting tech, I could have done with one of them at the little theatre I worked the lights at... :)
CTO (Correct To Orange) to adjust cold white closer to tungsten. But cuts out a lot of the light too.
of course leds lack light in certain wavelengths, the phosphurs cheat, but you get gaps even in the spectrum that they do cover, putting filters on top of that is probably going to lose more light than you expect.
what bench power supply do you use clive? cheers
It's really dodgy slimline Maplin one that seems good, but has a very odd (but common) quirk where it can crash once every so often and put out a random voltage. Hence why I never really mention it as I wouldn't recommend it.
hahahahah maplins quality shines though hahaha i managed to pick myself up an rs compononets thurlby 15v 4a for 15 quid at a car boot works a treat and very accurate
Hey Clive, did you just flick entire youtube @ 2:30? lol!
Middle finger isn't considered rude here except in an Americanism way. I just tend to point with a random finger.
I'm not bothered. I am not from America ;) And you are a legend, sir. Thanks for your videos!
I'd like to add my experience to the crappy eBay LED saga. I have a project that requires a decent amount of light. I thought I'll need around 20 watts or so. So I bought a 100 watt chip, expecting a crappy device. I was planning on under driving it at 20 watts. The very strange thing is, I tested it as you have done previously, and it's perfect. All the diodes start glowing at exactly the same voltage (25-26 volts) and they are perfectly matched in brightness. I don't know why. Maybe it's a fluke, maybe they're using the drug dealer tactics of giving me a good product to start, and then switching to the crappy parts later. I don't know.
I'd love for someone to verify my findings. I tested a 100 watt warm white LED from the seller more-things (www.ebay.com/usr/more-things). I just now ordered a cool white to compare. I will post back here when it arrives and I test it. Maybe we can find a source of reliably good chips.