Low cost decent CRI emitters by Toshiba?

mrheosuper · 2018-07-21T08:06:27.000Z

are you gonna do a group buy, if yes then i want 200 of them, 4000K cri 80 would be nice

djozz · 2018-07-21T08:55:34.000Z

For a flashlight the cost of the emitter is usually a small fraction of the build cost, so it makes sense to go for the best led out there no matter its cost (and that is what we do).

mrheosuper has the right purpose for this led, use a lot of them in a lighting project, in which case costs matter.

mrheosuper · 2018-07-21T09:03:47.000Z

djozz:

For a flashlight the cost of the emitter is usually a small fraction of the build cost, so it makes sense to go for the best led out there no matter its cost (and that is what we do).

mrheosuper has the right purpose for this led, use a lot of them in a lighting project, in which case costs matter.

yeah, i think i gonna make a table lamp, this led is reasonable, 10 of them cost only 1.5$ but will give you over 3000 lumen
and more led also means heat will spread more even, so you don’t need MCPCB cooper to have over 1000 lumen

ControlTheController · 2018-07-21T09:33:41.000Z

mrheosuper:

are you gonna do a group buy, if yes then i want 200 of them, 4000K cri 80 would be nice

Unfortunately my financial status doesn’t allow me to do a group buy, unless buyers pay in advance. I am bound by a considerably large amount of work currently. I will try to figure out the shipping, confirm the price, etc… ,and I might start a group buy, depending on the demand.

DavidEF · 2018-07-21T11:29:10.000Z

Pre-paid group buys are sometimes done around here. That wouldn’t be a big deal. The trick is getting a large enough reduction in price to make the group buy worthwhile. If these LEDs are already so cheap, I don’t know if it will be possible. Especially if you were going to be the one buying, receiving, and then re-shipping the LEDs. In that case, your price break would have to overcome the extra shipping cost and still offer value to the group buy participants and to yourself.

I’m not trying to talk you out of it. I would buy probably over 100 myself if you were able to get it low enough price. :innocent:

kiriba-ru · 2018-07-21T11:32:01.000Z

djozz:

For a flashlight the cost of the emitter is usually a small fraction of the build cost, so it makes sense to go for the best led out there no matter its cost (and that is what we do).

Unless you need dozen of them

ControlTheController · 2018-07-21T11:50:39.000Z

DavidEF:

Pre-paid group buys are sometimes done around here. That wouldn’t be a big deal. The trick is getting a large enough reduction in price to make the group buy worthwhile. If these LEDs are already so cheap, I don’t know if it will be possible. Especially if you were going to be the one buying, receiving, and then re-shipping the LEDs. In that case, your price break would have to overcome the extra shipping cost and still offer value to the group buy participants and to yourself.

I’m not trying to talk you out of it. I would buy probably over 100 myself if you were able to get it low enough price. :innocent:

Thank you for reminding me other factors to concern when considering a group buy! Seems that I need to do some calculations if I want to start one. :face_with_monocle:
I still have a lot to learn as I am still pretty new here…

DavidEF · 2018-07-21T12:25:47.000Z

The 4000K Toshiba TL1L3 listed at Digikey claims to have forward voltage of 2.85V @350mA and output 129lm. Just from this one datapoint, I compared to CREE PCT and found that it sorta lines up with XP-G2 and/or XP-G3, both at R2 bin. I don’t know if the whole curve is similar without looking at the datasheets, but that’s roughly where it falls in comparison to CREE.

The Digikey site lists them as an “obsolete item”. AliExpress has some listed for $5.41 for a lot of ten pieces. I’d say it’s worth buying to our hearts’ content at the price ControlTheController claims to be able to get them for.

ControlTheController · 2018-07-21T12:39:53.000Z

DavidEF:

The 4000K Toshiba TL1L3 listed at Digikey claims to have forward voltage of 2.85V @350mA and output 129lm. Just from this one datapoint, I compared to CREE PCT and found that it sorta lines up with XP-G2 and/or XP-G3, both at R2 bin. I don’t know if the whole curve is similar without looking at the datasheets, but that’s roughly where it falls in comparison to CREE.

The Digikey site lists them as an “obsolete item”. AliExpress has some listed for $5.41 for a lot of ten pieces. I’d say it’s worth buying to our hearts’ content at the price ControlTheController claims to be able to get them for.

The vendor will provide a 12.5% discount for orders ≥10000, but I doubt if there is that much demand. The price/performace ratio of this emitter seems unbeatable. I am leaning towards helping those that are interested to get some, rather than starting a formal group buy. I am also interested in what it can do. I may order a small quantity first, but I do not have the right equipment to test it. I wonder if there is a possibility that someone is willing to test these?

DavidEF · 2018-07-21T12:50:16.000Z

ControlTheController:

The vendor will provide a 12.5% discount for orders ≥10000, but I doubt if there is that much demand. The price/performance ratio of this emitter seems unbeatable. I am leaning towards helping those that are interested to get some, rather than starting a formal group buy. I am also interested in what it can do. I may order a small quantity first, but I do not have the right equipment to test it. I wonder if there is a possibility that someone is willing to test these?

Well, 10000 is just 100 x 100, so it actually is (barely) within the realm of possibility. Even without that extra 12.5% though, your price is already a lot lower than the AliExpress seller I referenced above. And, as you say, “The price/performance ratio of this emitter seems unbeatable”.

There are a few guys around here that do extensive LED testing, but for something in this range of old age and middling performance specs, you probably would have to supply the LEDs to them to get them tested, because I doubt they’d spend their own money for an older, middle-of-the-road emitter. (to test them)

snakebite · 2018-07-21T23:57:31.000Z

just looked and have bad news.
the heatsink pad connects to the anode!
no dtp stars for these!
as long as your mcpcb isolates it they will still work.

snakebite · 2018-07-22T00:04:22.000Z

pdf

kiriba-ru · 2018-07-22T06:47:11.000Z

How many years should past until everyone get the idea that good isolated pcb (led4power) dont limit anything in comparation with dtp?

mrheosuper · 2018-07-22T07:13:37.000Z

snakebite:

just looked and have bad news.
the heatsink pad connects to the anode!
no dtp stars for these!
as long as your mcpcb isolates it they will still work.

well, since this led is low power compared to other led like xpl or nichia, alumium board can do just fine
unless if you want to get any last juice from it, but in my case i won’t

Agro · 2018-07-22T10:12:58.000Z

kiriba-ru:

How many years should past until everyone get the idea that good isolated pcb (led4power) dont limit anything in comparation with dtp?

We’re talking about the case where low price is the entire point.

kiriba-ru · 2018-07-22T10:19:59.000Z

And? What changes from this?

Agro · 2018-07-22T11:22:23.000Z

Led4Power / clemence pcbs aren’t cheap.

kiriba-ru · 2018-07-22T11:29:29.000Z

You are funny. DTP pcbs are cheap?
Regular isolated plates is more common and cheap technology. Anyone can make his own gerbers and order full sheet from china, from $50/sq. m.

Agro · 2018-07-22T19:47:40.000Z

True, with these LEDs even regular DTP are economically a severe overkill. Still, high-end stuff is just even more out of place.
And in general….these may be as good as DTP or may not. djozz has seen underperforming Blackie HWQP. Led4Power non-DTP coupled with extreme power density of this LED is one, still unproven, suspect.

DavidEF · 2018-07-23T20:33:21.000Z

kiriba-ru:

How many years should past until everyone get the idea that good isolated pcb (led4power) dont limit anything in comparation with dtp?

Well, I see that I’ve missed the bulk of this conversation already, but I will add that this is just not a true statement. A non-DTP board cannot match 100% a DTP board. In some cases (in a low power light, or if there is a bad thermal path limiting in other areas, etc.) it can work as good, but not 100% every case. There will always be at least one possible use where the DTP succeeds and the non-DTP fails. This is because we’re not (usually) keeping everything within the bounds of manufacturer specs here. We’ve seen people push LEDs to the limits in both directions. Even the slight manufacturing differences among emitters that are rated the same show up as catastrophic failures at times. Even a completely unknown and undocumented difference between two manufacturers of the ‘same’ product (AMC7135 chips) has made the difference in whether a particular use case works or not. Maybe one day someone will make a MCPCB where the isolation layer material has ‘exactly’ the same thermal properties as the metal core. Until then, it CAN’T be true that they “dont limit anything in comparation with dtp”.