Well, just remember that Cree hit the 300 lm/w efficiency at a very low current. So, of course, there can still be improvements just by making the efficiency go up in higher current scenarios. A “perfect” LED would have to be one that could never burn out at any current. If there’s no heat, how could it? So, there is definitely a long way to go still. 
I still vote for your design fritz. Its really an elegant flashlight.
Sorry, you’re reading that wrong. Luminous efficacy - Wikipedia
100% luminous efficacy is 683lm with 1W.
The theoretical maximum of an LED is 260-300 which it says right beside is 38.1–43.9 efficiency.
Driving an XHP70 at 12A requires 7.5v, which is 12*7.5=90W. At this current it produces slightly over 5000lm, so you get 5000/90 = 55.6lm/W
If you look on the wikipedia page, in the first chart, 54.7lm/W is 8% efficiency. So basically for the XHP70 7.2W are turning into light, and 82.8W are going into heat.
No, the 683lm are for 555 nm. For a different wavelength this value is lower.
It says for an LED that 300lm is 43.9% efficiency.
300/0.439 = 683.4lm
So that means an LED working at peak efficiency 300lm/W will only be converting 43.9% of the power into light.
I quote the first sentence in the wikipedia article
So for green the Luminous efficacy is 100%. That means we see green light best. However, we don’t see other wavelengths as good as green. So what we perceive as 683 lm in green, we just perceive as around 300 lm in a different wavelength.
Same number used as fritz15, only the model has changed.
Total time is 600 seconds, time steps are 60 seconds.
(pictures are cross-sections, click for full version)
Here it is with 40 watts:
Here it is with 120 watts:
I feel that Fritz15’s design is most pleasing on the eyes - the most harmonious design - and it has the possibility to mount carrying handel. I really like that.
Not a very big flashlight, but a searchlight.
.
Having said that, I could certainly live with 5AR’s design
And a well meant suggestion on that design: the head is, of course, very big and the body relatively small.
No problem, that is the basic design that was agreed upon.
However, it could be made more aesthetically hormonious by adding a much larger tailcap, in which anti-roll could be incorporated, no?
.
Just a suggestion, of course :+1:
Grtz
Nico
All of the lights will have the ability to use a tripod mounted carry handle. None of them will come with any other form of handle.
I think fritz15 is right. The 683lm/W is for 555nm light, and this is practically irrelevant for us because our LEDs are “white”. The luminous efficacy depends on the spectrum, so that efficiency column in the wikipedia article is misleading because it compares every luminous efficacy to that of 555nm light, which hardly relevant.
The 260-300 lm/W value for LEDs is the theoretical maximum given the typical LED spectrum (blue peak and a yellowish peak) and it represents 100% conversion of input power to photons.
It seems we know that is not the case since LED’s making those kind of numbers still get hot, thus not all the power is going to photons?
This is the reference wikipedia quotes for the 260-300lm/W number and it explains with a bit more context:
They have made white LEDs close to the theoretical efficiency, but only with very small outputs. I can see why you might be a bit skeptical that it would produce very little heat (proportionally), but it looks like it is the case.
Edit: here is another reference from that wikipedia page: [1309.7039] Maximum Spectral Luminous Efficacy of White Light
They calculate the maximum efficacy of truncated black body spectra; they only consider the part of the spectrum that is within the visible wavelength range. They get numbers around 250-350lm/W. A truncated black body spectrum is approximately what a white LED spectrum looks like; light is only produced in the visible range.
This light deserves a beautiful designed BLF GT logo. I don’t really like the current logo :zipper_mouth_face:
It could indeed use a nice logo, if people want to come up with ideas a poll can be held for that later
Allright guys, i’m done wrestling with the pixels…
Must say i ran into the limits of what i work with quite often, and still i had many many options, but i think it ain’t half bad like this:
The shelf for the LED sits in the middle of the fins.
Simple lines, not only because it’s very difficult (for me) to do otherwise, but also with the production costs in mind.
And i like simple lines too. 
The anti rolling blocks are now milled into the head, which is easier to do properly.
This is with a 100mm deep reflector.
I hope you like it, although i only have this simple view of it, i have no 3D model.
Nice work Jerommel ! These are all really sweet.
Nice pics Jerommel, I like the one on the right the most. Albeit you put a lot of effort in it I have to confess I like Fritz 15 light more. But as you say, yours will be easier to manufacture, less milling.
Maybe i do too.
I do think though he should swap the finned part with the ring part of the ‘light engine’.
Should be simple to do i.m.o.
5ar, your renderings are awesome. :+1:
Here is my design.
All pictures are clickable.
- Shoulder strap connections on head and battery tube
- Tripod mount at exact the Center of Mass (Center of mass is the black and white mark in the pictures)
- Side switch (IMO there is no reason for tailswitch, but can be made)
- Imaging the battery tube with full knurling
- I left some room above the battery carrier because there are no battery springs, the room should make up for that
- There is a pocket especially for the led (26mm diameter)
- Driver pocket (45mm diameter in this design)
- Head consists of 2 parts for easy modding, light can be used as a candle without top part
- Good thermal characteristics
5ar you can use this picture to photoshop it next to fritz and your light for comparison.
