Many thanks to Sofirn for sharing that testing! I shall inform gurdygurds that this light appears to be prepared for his gauntlet.
I had to disable my ad blocker to get the videos to play.
Thatās close to the worst case specified performance. Best case is 2.7V and 8 lm at 20mA, which would be 148 lm/W.
Considering this is a 95+ CRI emitter, anywhere in that range is pretty decent, and the high end is good enough to be hard for me to believe. When djozz tested an 80+ CRI Nichia 219C, his numbers at the closest datapoint to the rated current worked out to 139 lm/W.
Thanks for the details about the led being used.
Why not have three of them and get read of the useless reflector to triple the output?
That would not add much complexity and should not impede robustness either?
Sorry about the argument but iām having a hard time wrapping my mind around a new 2018 light putting out only 8 lumenā¦
It is much more about runtime as it is about output, it is build as a last resort light, 8 lumen compared to no light at all is huge, also in 2018.
But what that 95CRI does in a last resort light is highly questionable of course 
I think the last of the videoās, they did it rather carefully instead of full speed, but they did succesfully run it over by a truck 
[video: http://v.youku.com/v_show/id_XMzgyOTI5ODQ3Ng==.html?spm=a2h3j.8428770.3416059.1 ]
What does ANY kid do, when you give him a flashlight, no matter - as a gift, or to use for a short while? :smiling_imp:
Literally, every child turns it on and looks into the bulb/led, whatever the ligh source. When the kid has made sure there are no monsters under the bed and in the dark bathroom, he or she drops the flashlight on concrete floor, in water, disassembles it, changes polarity of the battery, whatever. Afterwards, if the flashlight has survived, he / she leaves it onā¦
Donāt you still see a use for a 8 lumen, crash, water and freeze safe flashlight in 2018? The only issue left in this is disassemblingā¦
Barry mailed me some other test results, mail=below. He is concerned that we think the output is too little. But we decided on 25mA because of durability and of runtime, so the output is what it is when you use these Yuji leds. They may come with a cool white low CRI version at some point, that would have an output over 10 lumen.
Sorry, maybe this posted allready.
How hot they get after 10-20 min continous work
Hmm, hot?
They run at 25mA, that is ~75mA on the battery, on average 1.2V so 0.09W, of which 0.06W is heat. After 20 minutes the light may feel slightly luke-warm, probably not at all.
Any chance we can bump it up to 35 mA? The beam is more diffused than an E01 which means itās really going to be difficult to use this unless in complete darkness.
Especially with the warm white at 5.5 lumens, Iām concerned whether this light will have any everyday use at all.
Would also like to know whatās the lowest battery voltage this baby fires at.
That would be an interesting add, if it will be a later option!
So far, Iām happy with the results and I donāt think this kind of light would need much more. It is what it is, it will serve for the designated purposes! I wanna stick a battery into it, forget it is there, and then, when needed, use it for the longest time possible.
I (colective āIā, meaning most of us) will - probably - have other lights to use with more output.
Thanks again for all the tests and work so far! BTW, I guess this light can also be used as a āthrowerā: you throw it to someoneās head andā¦good luck to that someoneās head :smiling_imp:
You will have to accept that this light does not put out a lot of light, the current was discussed before and for sake of led lifetime and runtime of the flashlight it was (as discussed in this thread) decided on 25mA, as compromise between output and runtime.
You will be amazed if you have no other light than 5 lumens available how useful it is. One application, for me with its 60 degrees flood led it will be and ideal reading light without disturbing others around me who are asleep.
But search and rescueā¦no
I like the tests Sofirn has done, especially the rapid temperature change test (number 6) :THUMBS-UP: . An extreme version of this test would be if you did it the other way round (first cold, then hot): -35Ā°C for at least 30 min, then immediately put the light in hot water that has just boiled a moment before (~ 90Ā°C), I mean its a totally realistic scenario O:) , imagine you are working in the Arctic (or Antarctic) and forgot to bring a spoon, so you use your light to stir your freshly brewed coffee :D .
The lumen numbers (5,5 lm & 7,5 lm @ 25 mA) seem a bit below spec (the warm white quite a bit, the neutral white only slightly). If we were to increase the current to 30 mA we would get about 6,41 lm for the warm white and about 8,75 lm for the neutral white.
The question is if the slightly higher lumens are worth the trade-off in runtime.
At 25 mA and a power draw of 0,09 W from the battery (as per dijozz's calculation) we would get a calculated runtime of 10 h with a standard eneloop, a bit over 12 h from an alkaline and 20 h from an Energizer lithium.
At 30 mA and a power draw of 0,11 W we would get a calculated runtime of a bit over 8 h from an eneloop, 10 h from an alkaline and a bit over 16 h from an Energizer lithium.
Keep in mind these are only calculated runtimes, it would of course be great if Sofirn could do some runtime tests so that we have some proper data.
Would like to know that too, my guess and hope is that it will just keep draining the battery forever giving off less and less light.
I have told Barry that 25mA is what was decided on and that it is the perfect current for what this light is meant to be. We can keep discussing other currents but we had that discussion already and we will never be unanymous about it.
Perhaps Sofirn will come up in the future with a version with a reflector/TIR and high power SMD led, putting out 100-120 lumen, like all other manufacturers have in their portfolio also: more light, modes, less runtime, a bit less robust probably. But that is not this light.
Yes, 25 mA is a good choice/compromise for this light, both in terms of runtime and lifetime of the LED. The point of my calculation was more to show that you get very little extra lumens (only about 1 lm more) at quite a cost of runtime (roughly -20%, or ~ 2 h less).
Are colours decided? Definitively?
No, but the discussion about it isā¦ :innocent:
Some explananation: there has been a poll in this thread about a limited amount of colours that Sofirn mentioned to me as possibilities. Enough people responded in that poll that I could communicate clear preferences to Sofirn (Barry). Apart from the few colours that the poll was about, a lot of suggestions were done in the poll for other colours that were not part of the poll. I have also given a summary of those suggestions to Barry. In the meantime Sofirn seems not so limited on the colours that at first were given as the only options, so the final colour line-up may be different than what came out of the poll. Also, in case many lights will be sold, more colours may be a possibility.
So in the end Sofirn decides on which and how many colours will be produced, and they have already received a good indication of what we at BLF prefer, so IMO that is all we can do about the colour situation.
I add this as a point of reference, not to try and change your mind. I carried a AAA Thrunite Ti-3 on a long backpacking trip as my only light source. I used it every night for my lighting needs. That light has 3 modes, moonlight, low, and high. Advertised output was 0.04 lumen, 12 lumen and 120 lumen. I donāt have a way to measure the lumens myself. When I needed that light, I used it ~80% of the time on firefly, and it was just fine. This was outdoors, so no walls for reflection and not completely dark. 20 days of lightning needs in the fall on a single primary lithium. I still have that same battery in the light and it still is shining when needed. Itās not my EDC, but it gets used on occasion.
I would think if you need a bit of light, 5 lumens will work. you wonāt want to use it as a bike light, you wonāt be able to see what goes creak in the night. But if you need to see something at your feet or close range, especially inside a building, it will function and always be ready. Especially if you equip it with a lithium primary.
You are likely correct, this is likely not the light you want for an EDC. AT least for me, running at 35mA would still not make it an EDC light for me. It is definitely not the light I want for an EDC, but I am interested in it for some special uses, like stashing somewhere with a lithium primary and knowing there will be a light there when I need it. Or by my bed for lighting up the room a bit without turning on the overhead light.