Nichia E17A/E21A Skilhunt H04RC Group Buy

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clemence I think E21A may be is too big for this optics. Could you measure flux without host and optics ? or at least e21 vs e17 flux?

I’m really glad that maukka started selling his calibration lights and that so many of us have them. Before that those were available, people with real numbers would hesitate publishing them because they were a lot lower than the rest (I have noticed easily a variation of 30-40% among calibrations of different people), and the temptation was there to match your calibration to what was generally accepted (many flashlight manufacturrers did that too). My led tests always gave low-ish output numbers compared to “the rest” (BLF members and flashlight manufacturers), until maukka’s calibrated test rig showed that they were actually 7-11% high (depending on spectrum, my imperfect sphere coating generates limited but measurable spectrum errors).
But even apart from calibration differences, that since maukka’s lights are for sale have decimated, the fact that most people (including TA) use cheap luxmeters with very imprecise optical filters, is still a souce of error that can cause a variation that for some tints can be as high as 20% (see my luxmeter tests).

Sure that’s what I’m gonna do.

[Clemence]

Indeed, TA sphere pre-callibrated was a big step forward but the luxmeter is still holding it back.
Now that there’s Unit-T UT-383S this may be possible to significantly improve (but not solve) with reasonable cost increase…
Though one thing that worries me in this meter (aside from being untested) is its absence from Uni-Trend website.

I do not see how this luxmeter would change things, it is yet another cheap luxmeter that for sure will have optical filter errors. A good luxmeter filter that precisely corrects the sensor for the Vlambda curve is still very expensive (as in hundreds of dollars for the filter alone), and none of my tests sofar have proven otherwise. So there is no way around that, and errors of 10% upwards will remain. I have not tested this specific luxmeter but I have no illusions.

In your tests UT383 did way better than other cheap meters. If UT383S performs as well, it’s probably significantly better in the cool region HS1010A that TA uses.

If you look into the table I made of how the different meters measured a number of different flashlights, you will see that while it performs better than some others, the U383 depending on light source, measured from 5% too low to 15% too low so a 10% variation on top of the calibration error, which does not make it a great luxmeter, just better than the worst ones. That is quite a range of error to consider. There seems to be a performance in between, the one Extech meter that I tested differed only a few percent from the reference luxmeter, which also shows in the wavelength response.

Unfortunately no, this is not for you. This H04RC steps down in 2 minutes to ~50% max output. Less than 400lm continuous with R9080. You better look for bigger light, not a headlamp.

[Clemence]

Nichia Esttool simulation (proofed to be very accurate)

4x E21A sm355 D220 R9080 (Tj 85°C, 4P)

Mode 7 (800mA)

- 259,9 lm

- 2,665 V

- 122 lm/watt

  • 2,132 watt

Mode 8 (2500mA)

- 744,5 lm

- 2,8575 V

- 104 lm/watt

  • 7,144 watt
    —————————————-

4x E17A sm355 B11 R9080 (Tj 85°C, 4P)

Mode 7 (800mA)

- 248,6 lm

- 2,7825 V

- 112 lm/watt

  • 2,226 watt

Mode 8 (2500mA)

- 665,8 lm

- 3,01V

- 88 lm/watt

  • 7,525 watt

With E17A, optical efficiency would be higher but both regulation and heat generation are worse.
[Clemence]

But TA calibrates with reference lights which should cancel this error.
And I think $370 for Extech is way too high for an average enthusiast. At least I keep it out of my scope.

It’s hard to find a high CRI headlamp.

My 400-500lms figure is pretty rough anyway. When the H04RC steps down to 50% max output, what is it’s rough output? Just under 400lm?

Looks to be about 250 lumen

Vary depends on the LED CCT. For 3500K its 225lm. 6500K would be about 250lm

[Clemence]

I think we need to keep in mind that this would not be just an standard 90 CRI headlamp. The LED’s provided for this Group Buy are 9080 LED’s, with a very high R9 colour rendering.

From my experience, your pupils will dilate to adjust to the light provided by a headlamp/flashlight. A small compromise in brightness can easily be adjusted for with your eyes and brain, but not so for colours. Having the super high 9080 LED’s bring out colours that you would otherwise not see as well with a lower CRI option, regardless of intensity or lumen output.

No it does not, spectral errors are not solved by calibration, please read my luxmeter threads for an explanation.

True! I use 4 different calibrated lights from Maukka: 6600K R7O, 5000K R9050, 6500K R9585, and 2700 R9580. They all have different calibration values. I use value closer to the light tested

[Clemence]

I understand the spectral errors but misunderstood your previous post.

UT383 is the only cheap meter that you tested which doesn’t significantly overread the blue peak of cool low-CRI lights.
It loses at the far red. And the sensitivity peak is shifted. I don’t claim it’s great but to me it looks significantly better than anything up to several times its price.

@Clemence: that is a practical workaround to compensate for spectral errors, while your Tasi meter already is relatively good.

How about getting back on topic: the Nichia E17A/E21A Skilhunt H04RC Group Buy ?

Hi Clemence do we need to pay first before we received a confirmation of order.....

Thank you