pointless mods: a high CRI lighted tail (bonus: Cree XD16 test)

29 posts / 0 new
Last post
djozz
djozz's picture
Offline
Last seen: 4 hours 58 min ago
Joined: 09/07/2012 - 17:04
Posts: 17994
Location: Amsterdam
pointless mods: a high CRI lighted tail (bonus: Cree XD16 test)

A few years ago I bought these very compact tail clicky 16340 lights at Fasttech to be used as a host (they were only available for a short period), decent quality and threading, standard 16mm board, 17mm driver and Omten1288 switch, and it is the most compact 16340 tail clicky light I know except for the EagleTac D25C, smaller than the Ultrafire 602C and Supfire S1.

I modded one to a UV-light at the time but, anticipating on new better 16340 cells to come hopefully, last week I modded it again to become my latest EDC, with a 3000K 95CRI SST-20 and BLF-A6 driver, output 440 lumen of nice incandescent quality light.

Of course it needed a lighted tail (I do them in all my lights if possible), and one of my wishes was to make a warm high CRI firefly tail at some point so here is my go at that. Does one need high CRI in light that you can hardly see?

I tried warm white 0603 leds from ebay before, but even the ones that promised the cosiest light of all were horribly yellow. So when ordering at RS-online anyway, I added a few Cree XD16 2700K 80CRI to my order, those should have at least a few magnitudes better tint than the ebay leds.

On the BLF driver I soldered a 470 Ohm bleeder resistor. I chose a tail ring with 2 strings of 3 leds (one of PD68’s designs, this one), one that could be sanded back to 14mm to fit in the small host. I soldered 3 of the XD16 leds in place with a 8.9 kOhm resistor behind the string (left the second string of three leds un-occupied for now) and assembled the tail to see how that looked. The lighted tail had an ok colour but did not emit quite the cosy warm light intended. It was 0.01 lumen and just enough for my spectrometer to extract the colour data:

The specs of the XD16 were at least confirmed, 2616K (through the tailcap) and 83CRI Smile . But the spectrum shows a steep dive after 620nm, for cosier higher CRI light more red must be added. I had 645nm quite deep red 0603 leds that should do that job so I added the second string with 3 of those, behind a 2.2 kOhm resistor (you need some power to see deep into red).

After assembly it looked nice, but the red was not really apparent.

It did help the tint and spectrum though, but the 645nm leds (from Osram btw) look more like 660nm, perhaps the very low current gave that shift. I was at 2400K and 88 CRI, still slightly above the BBL.

I wanted to get under the BBL, and the 660nm was too far into the invisible part of the spectrum, so I swapped the 645nm leds for (more visible and more efficient) 633nm 0603 leds, still with the 2.2 kOhm resistor.

The red peak is at 640nm which is a nice add-up to the XD16 spectrum but it is too high, too much red, very atmospheric but not intended. The spectrometer software even refused to provide a CRI for this tint. So I changed the 2.2 kOhm of the red string to 4.7 kOhm.

That looked more balanced. And bingo:

The red peak has halved, that brought the colour temperature back from 1600K to 2000K, the tint closer to the BBL but still nicely under it for that good mood, and the CRI sky-rocketed to 95.2, with an R9 of 97.7. And indeed when the illumination is compared next to a 2000K R9050 E21A flashlight (a modded Tool AA) on a white wall, the tint looks exactly the same.

So mission accomplished, a very high CRI 0.01 lumen lighted tail Big Smile . Not entirely useless, it does make a very nice night stand. Btw, the current that it draws is 0.52 mA, which drains a 700mAh 16340 battery in about 2 months.

Now lunch, after lunch I will add a led-test of the XD16 2700K 80CRI.

Ok, the test. I had these XD16 leds anyway, and it is quite an insult to use these high power leds at .2 mA as I did, and the XD16 has only been tested once before (a nice test on his own custom board by EasyB, here) so I did a output test, same method as always, a description of the method can be found in my Cree XP-L test via my signature link. The led was reflowed on a Virence 16mm high performance ledboard. In the graph I added test of a few relevant ‘competitor’ leds with similar die size, although there are too many differences between the leds (domed/dedomed, different tints/CRI, die sizes not exactly the same) for a good direct comparison.

Without a long discussion, the XD16 is a very nice good performing led (mind that the led at test is a 2700K 80 CRI sample, a cool white one has 20% more output, bringing it at 5A very close to the famous dedomed XP-G2 S4 2B) that perhaps did not get the attention on BLF that it deserves (the beam it produces in a reflector light is very nice for example). It probably handles more current than the Nichia E17A and E21A because unlike those it has a ceramic base that sheds the heat from the middle of the die better than the Nichia’s that lack a substrate.

(Stereo pic)

Edited by: djozz on 03/03/2019 - 10:55
cetary
Offline
Last seen: 2 days 3 hours ago
Joined: 10/28/2018 - 20:41
Posts: 210
Location: virginia

I was thinking about doing a lit warm white tail cap light. I was also thinking about putting maybe a red transparent sheet between the rubber boot and the emitters to create an imperfect incandescent color light without a cheesy looking tail cap. You could probably do that with any color like incandescent green for that look. Just thinking aloud. Anyways, really cool build. I wish we could see it in person as pictures can’t do it justice. Like with the 2000K E21A. I thought that emitter would put out an unpleasant flat orange light, but it turned out to be a lovely orange/warm tint. It looks like SON-Deluxe/Deluxe HPS, but better. You can see some HPS lights being overdriven, and they may exhibit a more white-ish color like the 2000K E21A/SON-Deluxe.

Luminus has some 1800K SMD LEDs from Mouser like the XD16 that might be interesting candidates for future mods. There’s a 95 CRI varient to.

djozz
djozz's picture
Offline
Last seen: 4 hours 58 min ago
Joined: 09/07/2012 - 17:04
Posts: 17994
Location: Amsterdam

Yes I know, I have looked into the Luminus Cube leds, but last time I checked the 1800K 95CRI variant was nowhere for sale in small quantities. And Mouser is always troublesome for us Europeans because of the high shipping costs.

And of course it was fun to achieve it this way, I found it surprisingly easy to turn 2700K 80CRI into 95CRI by simply adding the right amount of red.

Btw, I ordered some 2700K 80 CRI Nichia NSSLT02A leds from leds.de that I just found yesterday, much cheaper than the XD16 for lighted tail use, 10 cent a piece.

cetary
Offline
Last seen: 2 days 3 hours ago
Joined: 10/28/2018 - 20:41
Posts: 210
Location: virginia

Is the color chromacity good? Do you see much of the warm white/red shifting behind that diffused tailcap boot?

Geuzzz
Geuzzz's picture
Offline
Last seen: 4 hours 26 min ago
Joined: 10/25/2015 - 10:27
Posts: 1457
Location: Netherlands

What a great way to waste time on pointless stuff.

djozz
djozz's picture
Offline
Last seen: 4 hours 58 min ago
Joined: 09/07/2012 - 17:04
Posts: 17994
Location: Amsterdam

cetary wrote:
Is the color chromacity good? Do you see much of the warm white/red shifting behind that diffused tailcap boot?

If you look directly at the tailcap you see the different colours of course but the illumination is completely blended within a few mm from the boot.
cetary
Offline
Last seen: 2 days 3 hours ago
Joined: 10/28/2018 - 20:41
Posts: 210
Location: virginia
Geuzzz wrote:
What a great way to waste time on pointless stuff.

I wouldn’t call this totally pointless. It’s a rare glimpse into spectral power distribution tuning and improving CRI/R9. Cool Time you enjoy wasting isn’t wasted time.

Supposedly Cree did something like this years ago in their light fixtures to help with how inefficient warm white emitters were in the reds, they used separate red emitters and warm white in the same street light fixture. I haven’t been able to find much more information on this though.

Djozz, I had a separate question. Did you get your 2000K E21A’s from Clemence?

Those NSSLT02’s look interesting. Hopefully with better deep reds making them an even better candidate for this R9 enhancement treatment. 98/99 R9 anyone?

djozz
djozz's picture
Offline
Last seen: 4 hours 58 min ago
Joined: 09/07/2012 - 17:04
Posts: 17994
Location: Amsterdam

Yes, they came from Clemence, I would not know another source for these rare leds, although leds.de (Lumitronix) has a good assortment of current Nichia leds.

cetary
Offline
Last seen: 2 days 3 hours ago
Joined: 10/28/2018 - 20:41
Posts: 210
Location: virginia

Ah, for some reason my 2000K E21A’s had showed a higher color temperature of 2350K in my tests. Even with a faceted reflector and a frosted lens blending the light, I couldn’t get the CCT lower. It makes me wonder as the E21A looks like overdriven SON/HPS and PC Amber looks like under-driven HPS/SON, I wonder if the Luminus 1800K cube will look like stock HPS but with high CRI.

djozz
djozz's picture
Offline
Last seen: 4 hours 58 min ago
Joined: 09/07/2012 - 17:04
Posts: 17994
Location: Amsterdam

Just checked: in my Tool AA on a 14500 battery, the E21A is driven at 1.1A, reads 2100K in the hotspot and 1970K in the spill just outside the hotspot, both slightly under the BBL. The Tool has a (quality looking) AR-coating on the lens though that can mess a littlebit with the tint.

cetary
Offline
Last seen: 2 days 3 hours ago
Joined: 10/28/2018 - 20:41
Posts: 210
Location: virginia

I have my setup in a quad with a 2.8 amp driver. Maybe, I’m not pushing the needed amps into the four emitters to get the color temperature down? Is it one of the cool white sst range that color temperature shifts on it’s drive currents, I think? It could be the optics at play like you said as well, and even metering equipment inaccuracy.

djozz
djozz's picture
Offline
Last seen: 4 hours 58 min ago
Joined: 09/07/2012 - 17:04
Posts: 17994
Location: Amsterdam

I hope it not metering inaccuracy because that is difficult to check, you mostly need to trust the manufacturer for that. The only check that I could do on my spectrometer myself is that I recorded a Helium lamp spectrum and at least all peaks were within the nanometer accurate. But that is not all that can be wrong.

As an addition to the OP, I wanted to reduce the red peak a bit more to see how that affected things, and at the same time get a bit more light overall, so I swapped the 8.9 kOhm resistor of the XD16 string to 4.7 kOhm. Result is 0.0016 lumen, so indeed a bit more Smile , but what happened to the tint?:

Again a bit higher CCT as expected, now 2210K, CRI similar with R9 a bit down (but still great) and R11 and R12 went up, but still just a bit under the BBL. I’m ok with that for a firefly illumination so I keep it this way.

Tally-ho
Tally-ho's picture
Offline
Last seen: 1 month 2 days ago
Joined: 07/23/2011 - 04:15
Posts: 1394
Location: France

djozz wrote:


clemence
clemence's picture
Offline
Last seen: 1 year 1 month ago
Joined: 07/12/2015 - 02:58
Posts: 2474
Location: Bali - Indonesia

Nice mod Djozz, now you just started a DIY CRI/CCT making! Thumbs Up Beer
You should try mixing those colored E17A you have. I guess mixing any warm white LEDs with Amber and Red E17A will create extremely warm CCT with excellent CRI. They have VERY wide spectrum band compared to normal colored LEDs. I tested them and surprised to see the Amber looks much better than LPS.

[Clemence]

cetary
Offline
Last seen: 2 days 3 hours ago
Joined: 10/28/2018 - 20:41
Posts: 210
Location: virginia

clemence wrote:
Nice mod Djozz, now you just started a DIY CRI/CCT making! Thumbs Up Beer
You should try mixing those colored E17A you have. I guess mixing any warm white LEDs with Amber and Red E17A will create extremely warm CCT with excellent CRI. They have VERY wide spectrum band compared to normal colored LEDs. I tested them and surprised to see the Amber looks much better than LPS.

[Clemence]

I agree. The XP-E2 PC Amber has a CRI of about 42, double that of HPS while retaining a very gold-ish color of under-driven HPS/SON.

staticx57
Offline
Last seen: 22 hours 12 min ago
Joined: 04/11/2016 - 00:43
Posts: 713
Location: New Jersey, United States

cetary wrote:
clemence wrote:
Nice mod Djozz, now you just started a DIY CRI/CCT making! Thumbs Up Beer
You should try mixing those colored E17A you have. I guess mixing any warm white LEDs with Amber and Red E17A will create extremely warm CCT with excellent CRI. They have VERY wide spectrum band compared to normal colored LEDs. I tested them and surprised to see the Amber looks much better than LPS.

[Clemence]

I agree. The XP-E2 PC Amber has a CRI of about 42, double that of HPS while retaining a very gold-ish color of under-driven HPS/SON.

If you are curious about the 1800k 90 CRI Luminus Cube:

Exact part number: 1616-1103-18-90

cetary
Offline
Last seen: 2 days 3 hours ago
Joined: 10/28/2018 - 20:41
Posts: 210
Location: virginia

Luminus is saying the Cube can be ran at 300 milliamp. With the DTP from Clemence, you think 700 milliamp drive with x2 7135 regulators would be good?

djozz
djozz's picture
Offline
Last seen: 4 hours 58 min ago
Joined: 09/07/2012 - 17:04
Posts: 17994
Location: Amsterdam

I never did anything with those colour E17A’s I’m afraid, but I will at some point, they are excellent for colour mixing.

Another day, another idea for a project. I remember that sometime 2013 I decided that I had made my perfect EDC flashlight (with 219A 92 CRI) and that my hobby was finished Facepalm

cetary
Offline
Last seen: 2 days 3 hours ago
Joined: 10/28/2018 - 20:41
Posts: 210
Location: virginia

djozz wrote:
I never did anything with those colour E17A’s I’m afraid, but I will at some point, they are excellent for colour mixing.

Another day, another idea for a project. I remember that sometime 2013 I decided that I had made my perfect EDC flashlight (with 219A 92 CRI) and that my hobby was finished Facepalm

What 219A was that, was it the warm white one from fasttech?

djozz
djozz's picture
Offline
Last seen: 4 hours 58 min ago
Joined: 09/07/2012 - 17:04
Posts: 17994
Location: Amsterdam

That was back in 2013, Fasttech did not exist at the time, I got them from Illumination Supply which is now Illumn.com. They were 4500K and it was then the only high CRI led that was used in flashlights.

MRsDNF
MRsDNF's picture
Offline
Last seen: 2 months 1 week ago
Joined: 12/22/2011 - 21:18
Posts: 13473
Location: A light beam away from the missus in the land of Aus.

Does the subject of LED lighting ever get brought up in your classes?

 

djozz quotes, "it came with chinese lettering that is chinese to me".

                      "My man mousehole needs one too"

old4570 said "I'm not an expert , so don't suffer from any such technical restrictions".

Old-Lumens. Highly admired and cherished member of Budget Light Forum. 11.5.2011 - 20.12.16. RIP.

 

djozz
djozz's picture
Offline
Last seen: 4 hours 58 min ago
Joined: 09/07/2012 - 17:04
Posts: 17994
Location: Amsterdam

MRsDNF wrote:
Does the subject of LED lighting ever get brought up in your classes?

No, we use 5mm leds every now and then as an example light source, that is as far as it goes.

And I made an array of colour leds from 630nm to 400nm for demonstration of the photo-electric effect (the ability of photons to free electrons out of certain alloys). But that has nothing to do with lighting.

But light efficiency, colour temperature, CRI etc. is not a subject at school.

MRsDNF
MRsDNF's picture
Offline
Last seen: 2 months 1 week ago
Joined: 12/22/2011 - 21:18
Posts: 13473
Location: A light beam away from the missus in the land of Aus.

So your students have no idea what you do in your leisure time? Smile

 

djozz quotes, "it came with chinese lettering that is chinese to me".

                      "My man mousehole needs one too"

old4570 said "I'm not an expert , so don't suffer from any such technical restrictions".

Old-Lumens. Highly admired and cherished member of Budget Light Forum. 11.5.2011 - 20.12.16. RIP.

 

clemence
clemence's picture
Offline
Last seen: 1 year 1 month ago
Joined: 07/12/2015 - 02:58
Posts: 2474
Location: Bali - Indonesia

MRsDNF wrote:
So your students have no idea what you do in your leisure time? Smile
LOL you made it sounds…. (can’t find the right appropriate words)

[Clemence]

MRsDNF
MRsDNF's picture
Offline
Last seen: 2 months 1 week ago
Joined: 12/22/2011 - 21:18
Posts: 13473
Location: A light beam away from the missus in the land of Aus.

The reason I ask is that when in secondary school someone would ask the science teacher a question like how is a nuclear bomb made and for the rest of the lesson we learnt very little except how a bomb was made. Facepalm

 

djozz quotes, "it came with chinese lettering that is chinese to me".

                      "My man mousehole needs one too"

old4570 said "I'm not an expert , so don't suffer from any such technical restrictions".

Old-Lumens. Highly admired and cherished member of Budget Light Forum. 11.5.2011 - 20.12.16. RIP.

 

djozz
djozz's picture
Offline
Last seen: 4 hours 58 min ago
Joined: 09/07/2012 - 17:04
Posts: 17994
Location: Amsterdam

MRsDNF wrote:
So your students have no idea what you do in your leisure time? Smile

Not a clue. 12-18 year olds on average hardly wonder what goes on in other people, let go showing interest in people older than themselves. But there are a few exceptions Smile Most student like me and if they notice it at all, they appreciate what I’m doing at school (assisting anything to do with practical work and experiments in the science subjects), but what I do in my spare time is well beyond their universe.
clemence
clemence's picture
Offline
Last seen: 1 year 1 month ago
Joined: 07/12/2015 - 02:58
Posts: 2474
Location: Bali - Indonesia
MRsDNF wrote:
The reason I ask is that when in secondary school someone would ask the science teacher a question like how is a nuclear bomb made and for the rest of the lesson we learnt very little except how a bomb was made. Facepalm

I had this moment too, but worse. In my 2nd senior high school, there was a time when a physic class teacher answered a question from my friend. He explained how rainbow made colors out from white sunlight. He did something so very stupid in my opinion as an 16 y.o student. He could explain a nature phenomenon but failed to understand the basic.

Student: “Sir, if rainbow came from white light then is it possible to combine those colors back to white?”
Teacher: “Of course we can with the help of a prism”
Student: “I tried mixing all primary water color pigments but it didn’t work, why is that?”
Teacher: “You have to be extremely accurate, a slight mistake won’t make it white”

Me: Facepalm Facepalm Facepalm Facepalm Facepalm

I got dumped (for being a constant brat) to this “lower grade” high school, and then I realized all the teachers were also (mostly) “lower grades”. My physics teacher in the former high school taught me that pigment color mixing is totally different from light mixing. I believe him because he demonstrated the difference in front of us. I’m sure Djozz also does this too.
I was a little doubtful Thomas with sharp tongue back then, only proofs could silent me.

[Clemence]

Sari33
Offline
Last seen: 3 hours 59 min ago
Joined: 07/17/2019 - 05:43
Posts: 449
Location: EU

This was an interesting project, it would be even more take it as the main lighting on adjustable color temperature light with the 3V Red led.
But are there any red or orange broadband LEDs instead narrow?

kennybobby
kennybobby's picture
Offline
Last seen: 1 hour 2 min ago
Joined: 05/10/2017 - 09:13
Posts: 945
Location: huntspatch, alabama

clemence wrote:

I had this moment too, but worse. In my 2nd senior high school, there was a time when a physic class teacher answered a question from my friend. He explained how rainbow made colors out from white sunlight. He did something so very stupid in my opinion as an 16 y.o student. He could explain a nature phenomenon but failed to understand the basic.

Student: “Sir, if rainbow came from white light then is it possible to combine those colors back to white?”
Teacher: “Of course we can with the help of a prism”
Student: “I tried mixing all primary water color pigments but it didn’t work, why is that?”
Teacher: “You have to be extremely accurate, a slight mistake won’t make it white”

I got dumped (for being a constant brat) to this “lower grade” high school, and then I realized all the teachers were also (mostly) “lower grades”. My physics teacher in the former high school taught me that pigment color mixing is totally different from light mixing. I believe him because he demonstrated the difference in front of us. I’m sure Djozz also does this too.
I was a little doubtful Thomas with sharp tongue back then, only proofs could silent me.

[Clemence]

Reminds me of a 4th grade exam question that i failed related to the mixing of all colors, i said white based upon light (sunlight and rainbows), but they were looking for black or brown based upon the reflection of light (mixing of paints).

Funny how you can’t remember any of the questions that you answered correctly, but the failed answers stick forever in your memory.

Now i used to think that i was cool,
drivin' around on fossil fuel,
until i saw what i was doin',
was drivin' down the road to ruin. --JT