Yuji high cri 5mm LEDS group buy

[Esko]

@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'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...

 

[ma tumba]

Now I am getting closer to my goal.

I got some ~$1 multiple 5mm UV LED flashlights from the bay: 9x, 12x, 21x. All the 9x are complete junk, some of the 12x and 21x are pretty decent, but I ended up just harvesting the "LE" from a better 12x

https://imgur.com/yGTwKki

which happened to fit Z44 bezel almost perfectly. So I replaced the UV LEDs with 5600K Yuji LEDs

https://imgur.com/RJRWn3k
https://imgur.com/kUabp9P

Since the "LE" is much shorter than a p60 drop-in, the 1x18350 Solarforce body with the "LE" installed would perfectly house an 18500 cell. So this is my host #1, which has 12x 5600K/45 deg LEDs.

https://imgur.com/3vQnZA9

With a freshly charged IMP 18500 cell I measured the current ~600ma, or ~50ma per led which is about 2.5x the nominal current. So the light should be ~200lm. The beam quality is fantastic, there is no indication of a cct shift (as compared to my 3V minimag 2xAA setup) which would indicate that the LEDs are severely overdriven. When I applied 3.7V to a single LED, the LED survived but the cct dramatically shifted to the blue. So I would not hesitate to use this 12x light as is.

However, I plan to mod the tail with a hand made qtc attenuator (as has been done by at least two CPF members: tofty and PCC). Just need to locate some of those qtc pills with reasonable shipping cost.

Next post will present an e1 with 9x LEDs

 

[ma tumba]

The 9x UV $1 light was a complete junk. The stock "light engine" was not even based on a PCB, just a piece of plastic with 9 pairs of holes to keep the 9x UV LEDs together.

But this gave me an idea, so this is the modified LE
https://i.imgur.com/vQNGLaq.jpg
https://i.imgur.com/vy0Bgqx.jpg

It happens to fit perfectly the bezel which DaFabricata made for alfa-compatible LE. It just screws into the bezel and stays there quite well. Eventually, I replaced this thick wire by a thinner one and left the ling pints to facilitate the contact.
https://i.imgur.com/DVlfUkV.jpg

The contact with the body is facilitated via those individual LED pins and since those pins are electrically connected with a wire, the overall contact with the body is very robust despite this very unprofessional solution.

Here is the business end
https://i.imgur.com/9Hg3JKg.jpg

This light has to be fed by a 3V CR123 since a fresh RcR123A *does* severely overdrive the LEDs shifting the cct considerably to the blue. I may put a 1 or 3 Ohm resistor under the spring to drop voltage down to ~3 - 3.2V, aiming at around 50 lumens. At 3V I would guesstimate the output to be ~20lm as the light is even fainter than 3x 5600K Onion ring in my A2.

If I like this setup in the long run I would order another, longer bezel from DaFabricata, so that there is no gap between the bezel and the body (which is now closed by the o-ring). This would also allow me to get back to that thick LED connecting wire so that the contact is provided by this wire and the bezel.

 

[LeanBurn]

Sweet ! I love all these different approaches and mods !