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Feeler for Yuji high cri power leds group buy

ma tumba

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The 5mm yuji leds are performing even beyond my original expectations so I am thinking now of trying their power 98 cri leds. The store offers sample packs of their two lines, each having 20x each of every color temp.

I think that at this point no one needs that much of these leds, so what about another group buy?

I invite all interested member to check this spreadsheet and indicate how many of each color temperature they may want in case this group buy actually happens. Posting here or to the spreadsheet is not a commitment, just an indication if the group buy is viable and a starting point for my negotiations with Yuji

https://docs.google.com/spreadsheets/d/10b90VKclVgg7CEZF0_b5EnpB6-2czg4QHv6eQ1PW96M/edit?usp=sharing
 
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neutralwhite

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Big thanks , if these LED's are for flashlights let me know ,
also whatever else they're for , if you could add me to the sheet for 5 x 5600, 5 x 4000.
hope that's correct ordering and ok.
I cant access the sheet from this phone for now.
 

ma tumba

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Can you post a link to these 98CRI LEDS that you refer to? All I can find are the ones listed on this page are COB type and they aren't really modifiable into a flashlight: https://store.yujiintl.com/collections/vtc-series
Yes, they are COB type ones. At the moment I see it as a quality vs useability situation. After trying the 5mm LEDs I know that I would not return to cree or nichia for a mule type light. The tint of these Yuji is by far superior to anything I have seen, they are in a different league and I am going to write more about this as soon as the 5mm LEDs from my group buy reach their destinations.

So I consider this COB LEDs group buy as a means to provide the LEDs to prospective modders in the hope that they find them great enough to design custom pills
 

LeanBurn

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Alberta
... The tint of these Yuji is by far superior to anything I have seen, they are in a different league ...

That's what I have been saying since I first lit one up...and until you see it in real life you just don't realize how good the tint and CRI from this lowly 5mm LED can be !
 

neutralwhite

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I have a modded photon with a Yuji 5600k 5mm!.
All my lights will have Yuji in them one day.
nichia are being blown back!.
 

Gt390

Newly Enlightened
Joined
Oct 4, 2016
Messages
118
Received my leds today. Will be putting one in an arc aaa that is already disassembled very soon. Will report on the resilts on the thread I started a month or so ago. Pretty excited to see what it looks like.
 

iamlucky13

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Oct 11, 2016
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Very tentatively interested, but I'm not sure I personally have a use for a non-square emitter with a non-common footprint (I don't think these are electrically compatible with PCB's masked for XP or XM chips, for example).

A short length of the VTC ribbon's would be interesting though. Unfortunately, no sample packs available, and the minimum order price is higher, but the price per LED is lower, and they can be sectioned into as few as 3 LED's running at 12V.

On the topic of group buys, I have been considering starting a group buy for the 135L 10W COBs. Not yet though unless somebody else wanted to organize it. Life is super busy, and I'd kind of like to see if there is a new 5mm product on the way that could go in a combined order. A comment in the previous group buy thread made it sound like there is.
 

iamlucky13

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This thread has been dormant, but I have looked into the possibilities more from time to time.

I found out a BLF member has proven the 5730 size Yuji's can work on an XP solder pad, despite not being designed to match.
http://budgetlightforum.com/node/54327

Digging into the specs I noticed the VTC series improvements occur not just in the expected blue/violet range, but also in the red range, which is really impressive. Still, from how good the BC series look, I'm sure the benefits must be subtle. There's also a relatively large efficacy and output tradeoff (about 40% fewer lumens), and the VTC's require a slightly higher voltage. So while I'm curious about the VTC series, I'd probably be just as happy tinkering with another package type of the BC series.

Here's a comparison of typical specs including products we know better:

Yuji VTC 5730
Yuji BC 5730
Nichia 219C R9050
Cree XP-L V5 70 CRI
CRI
98959370
R9 score (red)
907050 minimum< 0*
R12 score (blue)
906070*40*
Efficacy
72 lm/W104 lm/W122 lm/W149 lm/W
* Not specified in datasheet. Used one or more of maukka's measurements.

There's also a square 3030 size in BC-series only that looks better suited for flashlights and is more powerful than the 5730, but I don't know if it or the smaller 2835 can work on an XP pad.

It's rather unfortunate their sampler packs are so much more expensive (over twice the cost) than their single color temp packs. $2 each for 30 lumen emitters is a bit steep. They're actually cheaper pre-assembled into flex strips. Even better, those can be used in the as-received form without having to find a suitable MCPCB, or to desolder emitters from a short section to use for other projects.

On a final personal note, I'm strongly interested in modding my 18V tool light or building something from scratch with the ~1000 lumen BC-135L series COB's. I think there is a lot that can be done with this product, although not EDC flashlights.

I think I have identified viable mounting options, drivers, and optics, too, so I might be proposing a group buy of those in the near future, because I would only want 2 or 3, and the minimum order quantity is 10.
 
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ma tumba

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Iamlucky13, that is a great chunk of information and great analysis. I am glad that I am not alone in the quest for the best tinted light.

I've come to these COBs from somewhat different direction. After having tried different high cri options, I am done with any domed LED available for they all provide tint shift across the beam in both mule and reflectorized lights, which I can not tolerate. The best what I have had is McGizmo's 083B light engine in a mule, which I am very fond of, but still it is noticeably greener than 5600K 5mm Yuji LEDs.

So I have high expectations regarding those COB LEDs and my goal would be to squeeze an array of, say 5x5 those 2835 LEDs into an e-series head, coupled with some standard driver (eg H17F, as Vf of a 2835 is ~3V). Such a mule head would provide up to 500 lumens, which is quite impressive for this CRI.

I am not sure I understand the problem with non-standard footprints. I remember myself making printed boards using nail polish masks and acid bath 3+ decades ago, at home, and I am sure there are more advanced possibilities for that these days. So I am probably missing some important aspect of an LED PCB.

Regarding the group buy. Originally I seriously considered one of those sample packs but after having fun with 3200K 5mm LEDs I now understand why Don used just the 5600K version, for the Saphire. It is the sunlight tinted version that really shines at this CRI level, so now I would be OK with buying the 5600K or the 5000K version only. And VTC 2835 could be had for $47.5 per 100pc pack which is just a few $ more expensive than the BC version.
 
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iamlucky13

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I am not sure I understand the problem with non-standard footprints. I remember myself making printed boards using nail polish masks and acid bath 3+ decades ago, at home, and I am sure there are more advanced possibilities for that these days. So I am probably missing some important aspect of an LED PCB.

Actually, you're not missing anything, at least not anything I'm saying. Modifying or making at home your own PCB's simply isn't something I have experience with. Since I do at least know what is needed to use through hole or XP and XM footprint LED's, that's what I've been focusing on.

Regarding the group buy. Originally I seriously considered one of those sample packs but after having fun with 3200K 5mm LEDs I now understand why Don used just the 5600K version, for the Saphire. It is the sunlight tinted version that really shines at this CRI level, so now I would be OK with buying the 5600K or the 5000K version only. And VTC 2835 could be had for $47.5 per 100pc pack which is just a few $ more expensive than the BC version.

I haven't seen the 5600K version yet in person, but I do think they'd be a good choice, especially if used for higher output levels.
 

iamlucky13

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On a final personal note, I'm strongly interested in modding my 18V tool light or building something from scratch with the ~1000 lumen BC-135L series COB's. I think there is a lot that can be done with this product, although not EDC flashlights.

I think I have identified viable mounting options, drivers, and optics, too, so I might be proposing a group buy of those in the near future, because I would only want 2 or 3, and the minimum order quantity is 10.

Update on this:

Yuji put these on sale for 15% off. Because of the sale and unclear interest in a group buy, I decided to go ahead order a pack of the 3200K.

These should have an output of 800 lumens at their rated current, and 1100 lumens at their maximum current. A 700mA Buckpuck or Flexblock driver should power them around 900 lumens with an 18V tool battery, optionally with dimming, and I found a Carlco 30mm optic that should work with these.

I don't know for certain what the appearance will be with a third party optic, but if these turn out to really be the equivalent of 100 of the 5mm Yuji's color wise, I'm going to be happy as a clam.

I only wanted a couple, so I'll have several to sell when they arrive in a few weeks.
 

iamlucky13

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I have a tool light I actually used to use very often when working on projects around my house. Being self-standing and having a decent amount of battery capacity, it's pretty handy, but it's an old incandescent type, and it's throwier than it should be for up-close use. It looks just like this:
https://www.ryobitools.com/products/details/18v-flashlight

I want to modernize it and start using it more again.

And I want more Yuji light.

I'm toying with other ideas, as well, like maybe buying one of the cheap Skyray King clones to see if I can fit one in there, or making a plug-in light for over my workbench.
 

ma tumba

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Oct 7, 2013
Messages
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Location
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I have a tool light I actually used to use very often when working on projects around my house. Being self-standing and having a decent amount of battery capacity, it's pretty handy, but it's an old incandescent type, and it's throwier than it should be for up-close use. It looks just like this:
https://www.ryobitools.com/products/details/18v-flashlight

I want to modernize it and start using it more again.

And I want more Yuji light.

I'm toying with other ideas, as well, like maybe buying one of the cheap Skyray King clones to see if I can fit one in there, or making a plug-in light for over my workbench.
So you you went for the 3200K version mostly because you were used to the existing incand version?

Originally, I wanted to get only the 3200K version of the 5mm LEDs for use as an incand replacement but ended up using mostly the 5600K version which I originally intended to provide to other members only (so glad that some of the subscribers pulled off th group buy :)
 

iamlucky13

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So you you went for the 3200K version mostly because you were used to the existing incand version?

Originally, I wanted to get only the 3200K version of the 5mm LEDs for use as an incand replacement but ended up using mostly the 5600K version which I originally intended to provide to other members only (so glad that some of the subscribers pulled off th group buy :)

Partially. I'll also mainly be using this light in my home, after dark, where almost all of the existing lighting is 2700-3000K. I reconsidered numerous times whether to get the 5600K instead, on the expectation of a very clean, pure white light appearance, and decided to settle for getting the tint that wouldn't contrast with other lights it will be used around.

I'm still not certain I made the "best" choice, but I'm not going to worry about having made the "wrong" choice. I'm certain they'll be good even if they could have been better.
 
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