I’m sorry if some feel I’m clobbering this thread…
but anyone for a 400+ kcd 18350 light?
Your lumen numbers don’t make sense to me. The collar will reduce the light output compared to a pre-collimator. You also can’t use both at the same time. The pre-collomiator serves no purpose when a collar is used (unless you put it on top of the collar when using a main lens with very long focal length).
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Detailed measurements regarding the Wavien collar can be found here (in German).
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The Wavien collar collects 75% of the light of a de-domed LED and lets 25% through the hole in the middle. Since the luminance is increased by 120% you get 0.25 * 2.2 * 0.95 = 52.5. Thats how much light exits the collar compared to the total lumens of the LED. Since it is made out of glass and has a dialectric coating, it has a reflectance of >90 (I assumed 95). After that you need to calculate how much of this the main lens catches (most likely all of it) and what its transmission rate is (uncoated glass => 92).
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Some more in-depth knowledge regarding the collar (this comes from mem, the inventor of the collar):
It’s actually not important what coating it has in terms of normal reflectivity raiting. The LED is only really excited by the blue part of the spectrum. So you need a collar that reflects as much blue light as possible in the 450-460nm range.
A few years ago some guys in the German TLF forum tried to build their own collars out of polished stainless steel. It didn’t work very well because stainless steel doesn’t reflect a lot of blue light.
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Some obervations regarding pre-collimators:
There are limits to what a pre-collimator can do. Generally you can expect a pre-collimator to roughly double your otf lumens with a typical aspheric lens without reducing the candela (usually it reduces the effect of imperfections in the main lens so that you don’t actually lose any otf luenens because of transmission losses in the pre-collimator). If you want the highest possible otf lumens you will also need an aspheric lens with very short focal-length, less than F/D=1. If the focal length of the pre-collimator is too short you will get a larger hotspot, but also less candela.
:money_mouth_face: :+1:
First note: in all these cases I use a precollimator built to size. Which means that with 40 mm FL it will collect slightly less than 75. With 100 mm it will collect much more. With precollimator it’s (from memory) under 40 (still a lot despite 2 having strong lenses).
There is no problem to mount a custom collar on the sides of a precollimator. Or a tiny collar before it.
I adjusted the output to account for changing collar effect. How?
I used the calculator to know the actual amount of light collected by the lens and from that - what is left for the collar.
Then the intensity is:
(collarless output)/0.75²(actual collection)²)
Explanation:
1.19 is the lowest number in the TLF test
(actual reflectivity)/0.99 is reflectivity reduction
(actual collection)/0.75 for the first time scales output proportionally to actual collection
(actual collection)/0.75 for the second time scales intensity proportionally to the non-collecting area
I guess a part of the reason why your experience doesn’t match my numbers is quite short FL that I used. With longer FL:
- precollimator can be more useful in improving collection
- Waiven collar doesn’t collect all stray light, leaving some to hit the inactive part of the lens and the flashlight body near the lens.
Now what if we take the 18350/21700 zoomie above, apply this idea, but shake it up slightly….
The central LED would be the Blackie. Around it 8*Nichia E21 CRI 9080. We’ve got an 18350 pencil-beamer which outthrows TN42. Theoretically TN42vn too. And we’ve got a reasonably efficient hi-cri flooder in the same package.
Problems:
- more complicated driver
- yet another cost hike
- strong output discontinuity on the switch between E21 and Blackie
I think this thread is best used for generic discussions about future projects. It will be a whole lot easier to keep track of your new design if you create a dedicated thread for it. That way, none of your early design notes will get lost in this thread.
Good suggestion, thanks.
Continued here:
My only real desire for a future BLF-light is too underwhelming to gain enough traction, I mentioned it once, and here again, one can hope :innocent: :
a 3 xNiMhAA-in-series light (batteries side-by-side) with common lineair driver like the BLF-A6 FET+1 driver or a Narsil driver. Short, tube-style with a quad (to keep the length as short as possible) low voltage led (Luxeon V is the current lowest voltage led that fits a Carclo quad, that should be a great choice) . The dimensions should be as low as L=80mm, D=34mm, which is very significantly lower than any 4xAA lights out there. The output will be very efficient and over 1500 lumen for most of the runtime. At around 4A current draw the light does not need a stepdown to prevent self-destruction, it can be handy though to keep the temperature low enough to hold.
So extremely safe, high efficient output, great small size, and it takes the most common alkaline battery in the world as backup,
I personally think this is an excellent idea. :sunglasses: I was pleasantly surprised to see in HKJ’s review that you can actually shove 10A through an Eneloop. A compact light that pushes the capabilities of NiMH is certainly interesting in my opinion.
I’d buy that in a heartbeat.
Finding a nice and decently powerful light that is safer for my son and non-flashaholics would be very welcome.
Same here, I might buy 4 or 5. There are a whole bunch of use cases where NiMH is a better choice.
I think it is a great idea too, and would be a multiple buyer, depending on price.
:+1:
Still some interest in a 3xAA light. It is also interesting because the overhead voltage between a modern low voltage led and 3xNiMh-in-series is close to ideal again for lineair drivers (7135 based) or even FET-drivers: good efficiency and still good runtime in regulation.
I did a test holding a 3xAA carrier with switch (phosfor-bronze springs) against the head of my LuxeonV-modded D4. The Eneloops were not quite full but it gave me a steady 1250 lumen for the 10 seconds that I managed to keep the parts in place in the entrance hole of the sphere.
It would be an ideal high performance light for people who aren’t necessarily flashaholics.
I want the long version of that very light, with the three AAs placed nose-to-tail. I know it would be about 200mm / 8 inches long, but I like long lights 
Of course the various 4xAA lights out there fill that niche as well (D40A, EA41), the merit of this one is that it is exceptionally thin and short.
@Phlogiston: 3xAA in a tube would work just as well (even a bit better because the resistance in between the batteries is virtually zero), that is of course a matter of preference, I like stubby lights, you like long and thin.
But this one would be less expensive than either of those I imagine.
> Three AAs nose to tail
You can do this by combining tubes from a SK68 clone and a “3W Police” flashlight (see the lego thread)
I’ve still got a Brinkmann 3AA tube light in the “do something with this someday” bin.
Google finds a lot of other 3AA flashlights (limiting search with /Tools/verbatim, and then choosing /Images)
I’d like to see a djozz-inspired 3AA BLF light myself.
Now this is weird. Two emitters, one spot and one flood — and an infrared beam to decide how far away the subject is to balance power to the emitters.
What will they think of next?
(I’m waiting for the flashlight design where you click the button and the light head extends little propellers and flies over to hover and illuminate your target, while you control it from the battery tube)