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Thread: Yuji high cri 5mm LEDS group buy

  1. #121
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    Default Re: Yuji high cri 5mm LEDS group buy

    Just wanted to share the mods I've done so far.



    The round body A2 is my go-to outdoor light, it has a multi-mode calypsoii ring with 2x 3200x45 Yuji LEDs and 1x 5600x45 Yuji LED. With a Tad's adapter and his 140lm bulb this light is versatile enough to be the only light that I reasonably need, plus I llove the 2-way pocket clip.

    The 4 flats A2 has Koala ring with 3x 3200x45 Yuji LEDs

    The e1e has a Tad's adapter with a 5600x45 Yuji LED. Rather faint light but it has its use.

    The cheap off-the-bay clip-on reading light is a VERY useful thing. I modded two of them so that they provide a shadowless light for close-up work. Here are some details:

    The light:



    This is how it clips on my glasses:



    The guts:


    Here how it works





    Now I always carry two of these clip-ons in my bag.

    What I need to make besides these lights is a multimode light that holds a few tens of these 5600 LEDs so that total output would reach 100lm or more. Something like one of those cheap off-the bay headlamps but in a handier form factor:

    Last edited by ma tumba; 09-22-2017 at 09:46 AM.

  2. #122

    Default Re: Yuji high cri 5mm LEDS group buy

    Very clever idea with the clip-on lights.

    What is the multi-mode ring you mention that can hold 3 emitters? I can't seem to find anything about this.

  3. #123
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    Default Re: Yuji high cri 5mm LEDS group buy

    Quote Originally Posted by iamlucky13 View Post
    ....
    What is the multi-mode ring you mention that can hold 3 emitters? I can't seem to find anything about this.
    Calipsoii A2 Rings (single mode and multi mode) were made by @calipsoii but have been out of production for some time now ....

    http://www.candlepowerforums.com/vb/...d.php?t=309782

    Koala Onion Rings (single mode only) are (currently I believe) being made by @koala ...

    http://www.candlepowerforums.com/vb/...-A2-LED-rings)
    Last edited by archimedes; 09-25-2017 at 08:04 PM.
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  4. #124
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    Default Re: Yuji high cri 5mm LEDS group buy

    Thanks, archimedes for providing these links, I somehow failed to save them.

    Yesterday I tried two things:

    1. swapped the LEDs in one of my unused stock SF LED rings for Yujis and eventually killed the ring. One of the channels died and the other two while survived so far show visible flicker.

    2. swapped the central LED in the Headlamp shown in post 121. While the circuit survived, strong flicker also developed every time I switched this thing on, after s few seconds being on. So these Yujis seem to draw current too high for a typical 5mm light.

    And another observation: while the 3200x45 version provides that perfect incand like tint, the 3200x60 version is noticeably different. It consistently shows a bit of rosy tint so you can tell it is a LED. I am not saying that this tint is worse than that, just something to be aware of.

  5. #125

    Default Re: Yuji high cri 5mm LEDS group buy

    Thanks Archimedes. It continues to fascinate me how many useful accessories, drop-ins, and other gadgets the flashlight community has produced over the years.

    Ma tumba - I've noticed the Yuji's have a lower forward voltage than a lot of other LED's, especially older LED's. If I remember right, mine (not from this group buy) are rated at 2.8V. A Nichia GS would more typically be 3.1 V and could be as high as 3.5V.

    So your finding makes sense. Devices that control current via a resistor are most likely to be at risk of damage, but I suppose swapping the resistor might resolve that.

    I could also see there being an issue with a lower voltage LED in parallel with a higher voltage LED if they share the same current limiting resistor.

  6. #126
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    Default Re: Yuji high cri 5mm LEDS group buy

    @Ma tumba
    Do you plan a new group buy? I missed the last one. I'd be interested getting ~10 3200x45
    Still looking for Surefire G2 in Orange.
    If you have one you don't like please PM me.

  7. #127
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    Default Re: Yuji high cri 5mm LEDS group buy

    Quote Originally Posted by WarriorOfLight View Post
    @Ma tumba
    Do you plan a new group buy? I missed the last one. I'd be interested getting ~10 3200x45
    No, I dont as they increased the minimum purchse from 100pc to 1000pc and who needs that much.
    I have some 3200x60 that I dont need, so if you want them, let me know

  8. #128
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    Default Re: Yuji high cri 5mm LEDS group buy

    Quote Originally Posted by ma tumba View Post
    No, I dont as they increased the minimum purchse from 100pc to 1000pc and who needs that much.
    I have some 3200x60 that I dont need, so if you want them, let me know
    If you have extra I'd take some as well.

  9. #129
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    Default Re: Yuji high cri 5mm LEDS group buy

    Quote Originally Posted by teak View Post
    If you have extra I'd take some as well.
    Yes I do, how many do you need?

  10. #130
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    Default Re: Yuji high cri 5mm LEDS group buy

    Quote Originally Posted by ma tumba View Post
    Yes I do, how many do you need?
    Pm sent

  11. #131
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    Default Re: Yuji high cri 5mm LEDS group buy

    Quote Originally Posted by teak View Post
    Pm sent
    Replied

  12. #132
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    Default Re: Yuji high cri 5mm LEDS group buy

    Stupid me..

    The flickering in both SF LED ring and the headlamp was caused by the residual soldering acid that I failed to swipe away carefully. I think that when it gets hotter its electrical conductance rises and this effectively short circuits the LED. After I have removed that residual acid, the headlamp with the Yuji LED works great. Somewhat overdriven but no flicker whatsoever.

    So I plan to replace the 3x 1.5V alcailnes for 3x 1.2V eneloops and see how it works.

  13. #133
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    Default Re: Yuji high cri 5mm LEDS group buy

    A better mini mag mod.

    I found a single Yuji LED to be too dim for practical uses other than very close range examination. So here is a step forward: 5 LEDs in a 2xAA mini mag.



    Here is the rough board that I made with the pins of the central LED positioned so that they go directly to the socket. The LEDs press upon the lens so the original mag UI works the usual way. I had disposed off the reflector altogether.



    I would say that 5 LEDs are about right for day time use, especially with 2x 1.5V batteries. Two eneloops are OK, too, but the light is considerably dimmer with them.

    Will see how far the beam is useful at night.
    Last edited by ma tumba; 10-16-2017 at 07:14 AM.

  14. #134

    Default Re: Yuji high cri 5mm LEDS group buy

    Looks good!

    I wish I had more time to tinker like this, and more Yuji's. My latest crazy thought is maybe the driver could be scavenged from a Nitecore Tube to power a cluster of these in parallel in a 3xAAA body.

  15. #135
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    Default Re: Yuji high cri 5mm LEDS group buy

    Do you know where these would be perfect ? .... The @sunny_nites Micro ATL (!)

    http://www.candlepowerforums.com/vb/...-ATL-G3-and-G4

    Unfortunately, I haven't seen any postings for over a year
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  16. #136
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    Default Re: Yuji high cri 5mm LEDS group buy

    How many people are still interested in the 3200K?

  17. #137

    Default Re: Yuji high cri 5mm LEDS group buy

    Quote Originally Posted by eraursls1984 View Post
    How many people are still interested in the 3200K?
    I'd be interested in either color temperature, but if you're thinking of trying to organize another group buy, it doesn't seem likely that we'd be able to drum up enough interest to meet the new 1000 piece minimum order quantity.

  18. #138
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    Default Re: Yuji high cri 5mm LEDS group buy

    Quote Originally Posted by archimedes View Post
    Do you know where these would be perfect ? .... The @sunny_nites Micro ATL (!)

    http://www.candlepowerforums.com/vb/...-ATL-G3-and-G4

    Unfortunately, I haven't seen any postings for over a year
    These lights are very cool indeed, thank you for the link!

    I recall when I saw them for the first time I hesitated because they looked too massive for the rather low output, but yes, great LEDs would make sense there.

    What I am trying to understand now is what is the optimum number ol the LEDs in a flashlight. Five seem to be OK for close inspections but I would rather go up from this number. For a 1" head, one could fit up to 8 LEDs operating in parallel from 2xAA or 1x CR123, and this is probably just fine.

    However, I am now favoring a bigger head which would accomodate up to about 25 LEDs in parallel, plus a constant current driver like MicroPuck Boost DC LED Driver (500mA version), for a single eneloop or CR123, or a constant current buck driver (have yet to find an appropriate one) for a single RCR123 or a 18650.
    Last edited by ma tumba; 10-18-2017 at 12:00 PM.

  19. #139
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    Default Re: Yuji high cri 5mm LEDS group buy

    Quote Originally Posted by ma tumba View Post
    These lights are very cool indeed, thank you for the link!

    I recall when I saw them for the first time I hesitated because they looked too massive for the rather low output, but yes, great LEDs would make sense there.

    What I am trying to understand now is what is the optimum number ol the LEDs in a flashlight. Five seem to be OK for close inspections but I would rather go up from this number. For a 1" head, one could fit up to 8 LEDs operating in parallel from 2xAA or 1x CR123, and this is probably just fine.

    However, I am now favoring a bigger head which would accomodate up to about 25 LEDs in parallel, plus a constant current driver like MicroPuck Boost DC LED Driver (500mA version), for a single eneloop or CR123, or a constant current buck driver (have yet to find an appropriate one) for a single RCR123 or a 18650.

    Everything old is new again ...

    http://ledmuseum.candlepower.us/kl2.htm
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  20. #140
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    Default Re: Yuji high cri 5mm LEDS group buy

    Quote Originally Posted by archimedes View Post
    Everything old is new again ...

    http://ledmuseum.candlepower.us/kl2.htm
    So true!

  21. #141

    Default Re: Yuji high cri 5mm LEDS group buy

    Quote Originally Posted by ma tumba View Post
    Quote Originally Posted by WarriorOfLight View Post
    @Ma tumba
    Do you plan a new group buy? I missed the last one. I'd be interested getting ~10 3200x45
    No, I dont as they increased the minimum purchse from 100pc to 1000pc and who needs that much.
    Quote Originally Posted by iamlucky13 View Post
    I'd be interested in either color temperature, but if you're thinking of trying to organize another group buy, it doesn't seem likely that we'd be able to drum up enough interest to meet the new 1000 piece minimum order quantity.
    Anyone wanting to make a good and powerful video light (or modify existing ones) could easily use hundreds of leds.

    1000 leds (500*3200K + 500*5600K) would produce some 3500lm - 7000lm depending on the color temperature and it doesn't sound like overkill either. It would cost more than a commercially available and rather similar product though...
    In God we trust, all others bring data.

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