Which is the best 6V/12V LED?

Flashlight Modding and DIY Parts
1

Hello BLF!

I hope everyone has been doing well.

Here's a question for you all: Suppose you had the opportunity to create a compact, single cell general purpose flashlight with a single 6V or 12V emitter, with no consideration for any practical driver issues (assume you could have a magic driver which does whatever you want), which available emitter would you choose as your ultimate choice and why?

Clearly there will be compromises - a small-die LED like the XHP35 would work better for a more throwy flashlight, while a big LED like the XHP70.2 or a COB would be great for a floody. Some emitters have great efficiency but terrible tint shift, while others have a beautiful tint but aren't as bright. Some manufacturers have their own opinion, and the XHP70.2 looks like one of those choices. Zebralight and Trunite for example, chose the XHP70.2 for their flagship flashlights in the SC700d and T2 respectively. However, they do suffer for the unavoidable tint shift from the dome and flip-chip construction.

Compromises typically are between:

  • Luminous Efficiency (lm/W)
  • Luminance (cd/area)
  • Colour Temperature (K)
  • Duv (distance from black body curve), a.k.a. 'tint'
  • Tint Shift (physical beam artifacts in common optics, e.g. green spill, egg yolk centre etc)
  • Luminosity (total brightness)

In your opinion, what's your best balance? Here are some I have come across (and I'll add more if you bring them up and make a case for them!):

  • Cree XHP70.2
    • Pros - very high luminous efficiency; high power/thermal handling capability means extremely bright overall output; comes in decent high CRI
    • Cons - suffers from moderate tint-shift (green ring) in most reflectors, even OP, but can be mitigated with diffusers; generally tints tend to be a little green
    • Which is your favourite tint bin?
  • Cree XHP70.2 De-domed
    • Similar to XHP70.2 but I hear de-doming may help tint shift?
  • Cree XHP50.2
    • Smaller version of XHP70.2! Maybe you prefer this? What do you think are the pros and cons of this vs 70.2?
    • Perhaps comes in more bins which are possible to purchase (what is your favourite?)
  • Cree XHP35.2 HD
    • Similar to HI version, though HI seems all around better for a flashlight in general (or am I missing something?)
  • Cree XHP35.2 HI
    • Pros - high luminance, typically has quite nice tints (which is your favourite?); flat design avoids tint-shift
    • Cons - 3535 size means much less overall power handling capability compared to 5050 or 7070 LEDs
  • Cree MT-G2
    • The big one! 9090 size with perhaps the highest power handling capability, but its size makes finding non-custom optics tricky
  • Nichia 144AM
    • Pros - known for very nice overall tint in high CRI, with a caveat
    • Cons - suffers from strong egg-yolking in most reflectors; requires strong diffusing or honeycomb optics to maximize colour potential
  • Nichia NV4WB35AM
  • GeTian FC40 LED
    • Pros - supposedly extremely high CRI(95) possible with general reports of good tint (see https://budgetlightforum.com/t/-/58200), comes with no dome
    • Cons - not too much details are known about this LED yet, and 95CRI appears to be a custom GB run

Thanks everyone!

2

Maybe a sliced Nichia 144A, could possibly solve the egg yolk issue and bring down the duv, I wanted to try that but Clemence only has 5700K now (and still no economy shipping)

The NV4WB35AM could be a good XHP35 HI alternative but no availability. They are listed with R9080!

I tried slicing an XHP50.2 and overall the tint worsened (but tint shift decreased a bit).

3

In a lack of 1st gen XHP50 4500/5000k 90CRI, i’ve started converting to GT-FC40 and XHP35. Yeah, only 12V for me when it comes to high power.

Only few i have in 6V and those are emitters mentioned at the beggining

EDIT: i’m still waiting for someone to build for sale GXB172/202

EDIT2: my new favourite EDC is “small” Thrunite T2 with FC40, no tint shift, very high CRI and output

4

Ill take XHP50.2 because 5050 size have TIR optic choice and 20w power handling.

5

Oh, you were asking for bins...

Here are some available and some “hardly” available

XHP35B-H0-0000- 0D0UB450H

XHP35B-H0-0000- 0D0UB445H

XHP50A-00-0000- 0D0UG445G

XHP50A-00-0000- 0D0UH250G

XHP50B-00-0000- 0D0UH450G

GT-FC40 is available at Rngwn’s sales thread :)

XHP70 is just pointless beside FC40

6

Thefreeman - the NV4W seems like a really nice LED but you're right that I haven't seen anyone around make a flashlight with that LED. Thanks for pointing that out, as well as for your results with the XHP50.2 dedoming.

id30209, is there a reason for choosing the XHP50.A over the XHP50.Bs? I like the idea of the T2 as well, and it looks like the FC40 is an LED that some manufacturers should start trying out, though it seems like it does trade off overall output for light quality (which sounds like a trade-off you think is worth making), and at least I don't know how well it performs thermally compared to the XHP70.2. For the drivers, I have a few new ideas being worked on..

Quadrupel, yes the XHP50.2 is an all around nice LED; the XHP70.2 is a little large for many optics as you pointed out.

7

Choosing xhp50 over .2 is just because of nasty ttint shift in .2

First gen doesn’t have it BUT it does have donut hole in small reflectors. And that can be easily fixed with rushing the dome with scotchbrite :)

i’ve tried several types of adaptation of xhp50.2: slicing, frosting lens etc but output drops and yellowpiss corona is still there. Only 3000-4000k max is acceptable cause corona and hotspot come close (tint) and it doesn’t have to be reworked.

Same goes for XHP70 and it’s even worse than smaller bro.

Slicing is the only good way to improve .2’s but if you wanna go with “innocent” emitters then XHP50/70 is better option IMO. Except that donut hole...

So at the end you have xhp35 & FC40 without a need to be “upgraded”

GT-FC40 test

8

For XHP50.2, I have used XHP50B-00-0000-0D0UH250G (5.0K and 90CRI) and XHP50B-00-0000-0D0UH20E2 (5.7K and 90CRI). The one with 5.0K and 90CRI has very bad tint shift. The hot spot is very yellow, too. The other with 5.7K and 90CRI has very little tint shift. In fact, this is the least tint shift I have ever seen from Cree LED’s. There is no problem with either smooth or orange peel reflector.

I really like XHP50.2 with 5.7K and 90CRI. However, 5.7K is cool white, and I felt it was little too cool for the light I was going to make. So, I have checked NV4W144AM with sm503 and R9050. Indeed, it has the bad tint shift (egg yolk). Then, I have tried it with the honeycomb optic. It is good enough. I completed the light with 144AM. The only dislike is that the beam pattern is wide. I was not trying to make the light with narrow beam because I was using 4-die LED. But, the honeycomb effect made the beam even wider than I was hoping. Still, the overall result is good (tint shift, CCT, CRI, and beam pattern), and I have kept the light.

I also have used XHP50.1 with 5.7K and 90CRI. The focused beam has “the cross” in the center. The space between each die is visible. XHP50.2 has the phosphor between each die, so it does not have “the cross.” Besides “the cross,” XHP50.1 and XHP50.2 seems to be the same.

I am talking about somewhat subjective and personal, like tint, beam pattern, and so on. My preference is very specific, but XHP50.2 with 5.7K with 90CRI is good. It is just cool white if it is not the thing. 144AM is also good with honeycomb optic. The beam pattern might be too wide for some application.

If I can find XHP50.2 with lower CCT and 90CRI, it may bring the good result. However, I am not so confident with Cree LED’s with lower (than 5.0K) CCT. They tend to be more yellow and/or brown. It is just my experience. Again, it is subjective.

NV4WB35AM sounds very interesting. It looks like the bigger brother of E21A. I like E21A and have some lights with them. Hopefully, it will be available.

9

I can’t say for sure, but the Olight Odin lights have a quad die led I suspect is the Nichia NV4W…but I can’t prove it. It’s a really nice led for sure for sure.

10

Fooey. Gimme a MT-G2 with all its creamy white goodness.

11

How could I miss out the MT-G2? That's a particularly interesting LED for its power handling capability and multi-die construction, though it is a fairly big device. Lightbringer, are they any particular tints you enjoy for its 'creamy white goodness', and how do they perform under most optics?

12

I tried directly messaging Olight’s various support emails and could never get an answer on that LED, either.

13

I’ve only gotten the 5000K versions from FT, quite nice.

I got a few lights with the MT-G2 in them, but forgot which ones :person_facepalming:

I’d love to stuff one under a TIR lens, but most of those I’ve seen are in reflectors, and the beam’s quite nice, not fried-eggy, no rings, etc. Nice big fat hotspot, too, to make a great general-purpose light.

They also really shine (haha) as mules, no optix necessary.

14

I have a 5000k in a Mag with a bit TIR optic. All flood, loverly beam IMO.

I also have what I think is a 4000k in another Mag with a shallow OP reflector. This is my favourite tint of all of my lights.