LED suppliers - Page 1
Forum section: electronics / projects

author: Oaklander
author_rank: Regular Contributor
timestamp: August 16, 2018, 02:43:46 pm
content: So far I’ve used LEDs from Ebay. I can get thousand of them for under 10 USD. I have had no problems with them but I’m a bit concerned about their longevity. Therefore I looked for similar LEDs at Digikey but the price was many times higher. My product has over a thousand LEDs so price does make a difference.Is there something in between? I’d like to know what I’m buying but Digikey prices are a bit too high. How good are the Ebay LEDs anyway? Should I just keep using the Ebay LEDs?

author: wraper
author_rank: Unknown
timestamp: August 16, 2018, 02:47:52 pm
content: Many of them significantly decrease brightness over time time and reliability is not stellar. Significant amount of doa. If your product has over 1000 LEDs, I would assume that several LEDs will fail in 100% of the devices.

author: wraper
author_rank: Unknown
timestamp: August 16, 2018, 02:49:42 pm
content: Also digikey is the last place I would look at when concerned about price.

author: wraper
author_rank: Unknown
timestamp: August 16, 2018, 03:15:46 pm
content: I would look for part numbers say at Mouser and look for cheapest price athttps://octopart.com/. Also check TMEhttps://www.tme.eu/en/katalog/optoelectronics_100327/#id_category=100134&page=1&s_field=artykul&s_order=ASC

author: Ice-Tea
author_rank: Super Contributor
timestamp: August 16, 2018, 05:09:45 pm
content: Quote from: Oaklander on August 16, 2018, 02:43:46 pmAnything but this.If you have some decent volume contact some manufacturers (Kingbright, Liteon,...) directly.

author: james_s
author_rank: Super Contributor
timestamp: August 16, 2018, 05:16:19 pm
content: Even in small quantities you can buy directly from Kingbright. I bought some LED displays from them for a project several years ago, haven't looked at prices lately.The cheap white LEDs don't last long, but for other colors I've bought random ebay LEDs and never had one fail. The problem with that random stuff from China though is you don't really know what you're getting. Some of it is excellent, the next batch may not be.

author: Oaklander
author_rank: Regular Contributor
timestamp: August 16, 2018, 05:25:25 pm
content: Not knowing what I’m getting is really a problem. I don’t know how bright the LEDs are. I only know that the brightness is perfect for the application. Now it’s hard to create a replacement for the old design as there is nothing to compare the new LEDs to.

author: DaJMasta
author_rank: Super Contributor
timestamp: August 16, 2018, 05:31:20 pm
content: For indicators they probably work alright, but the ebay specials aren't really suitable for illumination or longevity.As with most of the super cheap components available, the quality control will be less, the testing will be less, and there are frequently overstated specs. That ends up translating to more DOA LEDs, less consistency between them (efficiency, maximum brightness, color temperature, etc.), and quite possibly running some at the rated test current will not last to spec. Hard to say without buying a whole bunch and actually testing them, but the QC and both having a full specification and living up to a full specification is why there's a price premium from a reputable name brand. I would definitely shop around if you're looking for production quantities, as mentioned some manufacturers will deal with you directly and other suppliers can often offer a better price.

author: Ice-Tea
author_rank: Super Contributor
timestamp: August 16, 2018, 06:14:48 pm
content: Quote from: Oaklander on August 16, 2018, 05:25:25 pmGet an assortment of well spec'd LEDs from digi, farnell whatever. Compare. Order comparable from Kingbright,...

author: Kjelt
author_rank: Super Contributor
timestamp: August 16, 2018, 07:20:58 pm
content: Quote from: Oaklander on August 16, 2018, 05:25:25 pmAre you running then on a fixed current? Can you alter the current lower if needed?Buy a lightmeter.Newer generation leds have higher lumens. Buy the latest or one or two generations ago if the prices are better and lower the current till you have the same lumens.

author: floobydust
author_rank: Super Contributor
timestamp: August 16, 2018, 07:41:49 pm
content: It's not the supplier, it's the LED manufacturer you have to settle on.I find Digikey has poor pricing and brightness on LED's. All the Cree ones I've bought were 20X the price yet bland brightness and just not worth it. Lumex was the worst whenever I sampled them.I find LED's from eBay out of Shenzen are great - much lower cost and brighter, many are polarity marked backwards for some reason. Kingbright is very good, I use them for production.Also your manufacturing, how you solder the LED's matters a lot for lifetime and failures.LED's are sensitive to soldering temperatures, and SMD reheat profile is unique so the PCB assembler has to follow that.

author: Oaklander
author_rank: Regular Contributor
timestamp: August 16, 2018, 09:03:56 pm
content: I didn’t know about Octopart. It’s a very good service. I did found some not that expensive LEDs with it.Probably the best thing to do is to measure the luminosity of my current system and design a replacement which would have similar brightness but better reliability and lower price. I can save a bit if I use less but brighter LEDs. The current design has so many components (mostly LEDs) that it’s quite expensive to assemble.

author: Oaklander
author_rank: Regular Contributor
timestamp: August 22, 2018, 09:05:22 pm
content: I have now prototyped with few types of LEDs and have found one that’s perfect for the application.The problem is that there seems to be only one distributor for this LED. Of course I could also try to buy directly from manufacturer which is Foryard. At first I would need 5000 of them. I wonder if it’s worth asking for a quote from the manufacturer or should I just buy from the distributor? I have no idea whether that quantity is OK or ridiculously small.

author: wraper
author_rank: Unknown
timestamp: August 22, 2018, 09:09:06 pm
content: 5000 pcs is nothing. I would not expect any savings even if they sell to you directly. I would find another similar LED as second source anyway. Shit happens and parts often get out of stock.

author: Kjelt
author_rank: Super Contributor
timestamp: August 22, 2018, 09:30:57 pm
content: That is two reels, not that much.

author: Oaklander
author_rank: Regular Contributor
timestamp: August 23, 2018, 07:33:01 am
content: Now I realized that I’ve only considered LEDs which have very wide beam. That’s useless for my application. I can reduce the number of LEDs to fifth of the old number by using LEDs with a more focused beam of light.

author: Kjelt
author_rank: Super Contributor
timestamp: August 23, 2018, 12:41:50 pm
content: Quote from: Oaklander on August 23, 2018, 07:33:01 amCan you elaborate or give some partnrs? AFAIK white leds are pretty diffused due to the yellow phosphor layer. You need an additional lens to focus the light. There are ledpackages with that lens on top but they are just as expensive as that you use a lenslayer on top (plastick sheet with multiple lenses in them on the exact spot the leds are going to be). But it all depends on your use-case.

author: wraper
author_rank: Unknown
timestamp: August 23, 2018, 03:02:57 pm
content: Quote from: Kjelt on August 23, 2018, 12:41:50 pmAngle depends on lens on the top. It's not like LED die emits the light in one direction anyway.QuoteOP did not say those to be SMD.

author: Oaklander
author_rank: Regular Contributor
timestamp: August 23, 2018, 03:43:37 pm
content: I think I'll try these next.http://www.cree.com/led-components/media/documents/CLM2D-GCC_BCC.pdfI'd need only 140 pcs. of them per unit. They are readily available and relatively inexpensive.

author: Kjelt
author_rank: Super Contributor
timestamp: August 23, 2018, 03:49:22 pm
content: Quote from: Oaklander on August 23, 2018, 03:43:37 pmThose are not white those are green and blue

author: Kjelt
author_rank: Super Contributor
timestamp: August 23, 2018, 03:52:55 pm
content: Quote from: wraper on August 23, 2018, 03:02:57 pmThat is what I said.QuoteTrue, that was my assumption based on that he uses thousands pieces.Seeing his choice above I am not that far off.

author: Oaklander
author_rank: Regular Contributor
timestamp: August 23, 2018, 04:21:46 pm
content: Quote from: Kjelt on August 23, 2018, 03:49:22 pmApparently I haven't mentioned anything about colorGreen is just what I want.

author: floobydust
author_rank: Super Contributor
timestamp: August 23, 2018, 05:58:06 pm
content: If you are doing a really large display then LED's that are colour-binned is important.You don't want emerald-green 525nm spots or blue-green 515nm mixed. Or maybe it's not an issue.Cree are the most expensive LED's and I find they constantly obsolete parts or change to some odd package. So you design in a part and it's gone in a year. I've been using vanilla SMD 3528 because everyone makes them and they are used in car dashboards. But no lens.

author: Kjelt
author_rank: Super Contributor
timestamp: August 23, 2018, 10:33:18 pm
content: Quote from: Oaklander on August 23, 2018, 04:21:46 pmOK..... now I am very curious where you use green lights for, traffic lights or gardens or ?

author: Oaklander
author_rank: Regular Contributor
timestamp: August 24, 2018, 08:35:12 am
content: Quote from: floobydust on August 23, 2018, 05:58:06 pmThat Cree one is by far the most inexpensive LED of similar specs. Some other manufacturers have comparable LEDs but their price is at least 2,5 times higher.My requirements are quite simple: green, SMD and 5 to 10 candelas.Quote from: Kjelt on August 23, 2018, 10:33:18 pmIt's a kind info display.

author: Ice-Tea
author_rank: Super Contributor
timestamp: August 24, 2018, 01:17:00 pm
content: Quote from: Oaklander on August 24, 2018, 08:35:12 amYou need to define that better. Dominant and/or peak wavelenght +/- a nm tolerance.Differnece between types is huge.

author: Oaklander
author_rank: Regular Contributor
timestamp: August 24, 2018, 08:31:35 pm
content: The exact color does not really matter. I'm sure that any LED which the manufacturer calls green will be green enough.

author: Ice-Tea
author_rank: Super Contributor
timestamp: August 25, 2018, 11:57:47 am
content: That is a wrong assumption, IMOH.