Nice pictures wolfdog1226!! Thanks for sharing…. 
I pray that pilot does work at any airline I frequent. 
I have next to zero knowledge about flashlight building, but from my experience with PC hardware, it looks like the biggest obstacle to cooling a flashlight is sinking the heat away from the emitters. CPUs, fets and other devices can have the coldplate of a heatsink directly applied. You obviously can’t put a coldplate on top of an LED emitter, and there doesn’t look like a good way to apply one unless you mounted it on the reverse side of the PCB.
If what I just said makes no sense, please forgive me.
Yep, that’s exactly how flashlights are cooled. The high-power LEDs we’re talking about have a third solder pad on the back, which is an electrically neutral thermal contact. That contact is soldered to a copper disk, which is in turn covered in thermal compound and screwed to the body of the flashlight, or other heatsinking system.
The “problem” with this is that the flashlight can absorb a tremendous amount of heat for the first few seconds until it warms up, but can only dissipate heat at a slower rate. Flashlight manufacturers capitalize on this to advertise extremely bright settings which can only function until the light heats up. I personally think this is fine, basically giving me free light. But a lot of people very reasonably argue that the manufacturers should at least advertise how much light can be produced once the flashlight has reached equilibrium and is trying to dissipate the heat created.
Okay, where’s nottawhackjob when you need him??
It doesn’t bother me too much as I know enough to be skeptical and I’m not really in to high lumens anyway.
However it seems the whole issue could be very easily resolved by updated the ANSI spec to require 2 numbers: output at 30 sec and average output over full runtime at room temperature without extra cooling. Or better yet, manufacturers could start publishing cooled and uncooled runtime graphs like reviewers do. Sadly though, neither of these is likely to happen.
You’re right, this is just an extension of the flawed ANSI FL1 rules.
Anyone who has been into flashlights since before 2009, when FL1 was published, will remember that it was a double-edged sword. On the one hand, before FL1 you couldn’t trust a single detail listed on a flashlight’s packaging. Independent flashlight reviews and runtime graphs were absolutely vital to understand a single thing about the flashlight you were buying. In that sense, the introduction of FL1 was wonderful, because it made all the measurements listed on the box consistent, if nothing else.
But, it also standardized some bad ideas. Before 2009, reviewers usually listed runtime to 50% of starting brightness, and FL1 dragged that down to only 10% (and even this shameful lie wasn’t good enough for some manufacturers). An Emisar D4 is a great example of what’s being complained about here; if it were tested in accordance with FL1 they could claim 3,000 lumens and 45 minutes. Under the old 50% numbers, we’d say the runtime was about 60 seconds.
Unsustainable turbo modes are not that different from a mass-market flashlight with Alkaline batteries, that has an FL1 runtime of 300 hours. The difference, and the reason I support turbo modes but not the latter, is that I can choose a mode where that does not happen.
The old rating system of “time to 50% brightness” worked 10 years ago, but simply isn’t relevant for today’s flashlights.
That’s because 10 years ago typical flashlight output was 100 lumens. A “high end” light might output 200 or maybe 300 lumens. Battery capacity, not heat, was the limiting factor in sustaining output back then. Those lights were going at max power and output would decline as battery voltage declined.
In 2009, if you had a light that was rated 1 hour to 50% brightness, used it for 1 hour and then turned it on 2 hours later it would start at 50% brightness and decline from there. That rating gave you a good idea of how much battery capacity was left and how many spare batteries you should bring.
In contrast, the limiting factor for today’s flashlights with unsustainable turbo modes is heat, not battery capacity. Today’s lights have thermal sensors and are programmed to intentionally reduce output to prevent injury to your hand.
For example, you can turn on a D4 at max turbo of 4300 lumens. Output will rapidly decline to 50% or less in 20 seconds or so. But if you turn it off and let it cool for 10 minutes, you can then turn it on again and still get 4000+ lumen output. The battery is still almost completely full.
Also, some (but not all) of today’s lights have regulation which can sustain a flat output at an intermediate mode until the cell is almost completely depleted. This is different from lights 10 years which tended to have no regulation.
I like the ANSI system. At least everything is standardized. However, I agree some changes would be helpful. Most useful would be having 3 measurements for each light:
- Maximum output - the max lumens the light can produce when cool on a fresh cell at turn-on.
- Turbo mode duration - how long the light can sustain turbo mode until step down to a lower mode, or for lights with gradual rampdowns how long it takes for output to drop to the level of the maximum sustained output.
- Maximum sustained output - the highest output the light can sustain while tailstanding in a 70 degrees F room.
This is why we have reviews… to cut through the BS.
You will never eliminate company marketing BS… but you can help keep some of them honest by detailing deficiencies or bogus claims in review content. And then you patronize those who are honest, or collectively force prices for those who aren’t to drop…
I think that the marketing is to blame more than anything. If a flashlight were called a 500 lumen flashlight because on High it had a sustainable 500 lumens for lets say…20 minutes straight. Then it had a turbo, or momentary mode that was 1500 lumens. It seems more reasonable to refer to the output that you could leave it on for a long time.
I also think that trying to find a way to cheaply and effectively pull more heat away is something that needs more exploring.
The guys complaining about high sustained turbo do not care about safety or damage to product. See wolf’s pictures above for reference. Look at his hands. Burn of some type for sure.
I like turbo for great amounts of light BUTI look at safety factor MORE than turbo sustained mode. NO SAFETY step down one gets injured or possible death quite simple.
I like to see output tied to dt of temperature.
Example……Xlight can put out 500 lumens for three hours in 70 degree temperature. Lower times in higher temperature environment.
Then give muggles the option of blowing on it. “15 blows per minute will extent high output. Beware of passing out”
Well we can extend this argument with candela numbers too. Calculated throw versus real. The circumstances are like the cartoon where Daffy Duck tries to sell insurance to Elmer Fudd - “Stampede of wild elephants. 3:57pm. Fourth of July. Hailstorm… and one baby zebra…” But such is the nature of the beast - not everyone uses the same batteries, not everyone has the same usage for a particular light, the weather and conditions will always be different. Heck, except for some custom builders, aside from checking that the lights turn on and off (if they even do that) it’s not like each light is checked [by the manufacturer] with an integrating sphere for output, measured for candela, etc… Even if a reel of LEDs were spec’d with a specific bin, it does not guarantee every light made from that batch will have the same output, as there are variations in electronics too.
I think it would be brave for a manufacturer to guarantee that the light you receive, when used with the specified batteries, will output to within 5% of the advertised ratings, instead of “pot luck” numbers…
lol!!! My hand was NOT burnt! I have leather hands and a high tolerance to pain! About 10 minutes after that photo they were back to normal.
MOST people would NOT run alight as long as me in the summer time.They would dial down after 4 to 5 minutes.
I LOVE Turbo! That was after 10 minutes straight of Turbo in 76F to 80F temps,then low for 3 or 4 than Turbo again.
NO HARM done to light as it has a thermal step down which has yet to activate. I run it on Turbo 100% of the time in the late fall and winter.
Tonight is going to be very cold for my area, ~ 10F/-12C @ 7PM,My morning hike @ 5AM will be –3F/-19C. :+1:
No worries about my hand getting red from heat, maybe red and numb from cold! 
Grazie Mille
:+1: :sunglasses:
We need to define some "flashlight benchmark" which would take into account most important flashlight characteristics, for example, that factor could be derived from equations that look something like this:
Flashlight lumen benchmark = Light_output_max [lm] * Run_time_till_90%_of_max [sec] / Flashlight_mass_with_batteries [g]
Flashlight candela benchmark = Luminous_intensity_max [cd] * Run_time_till_90%_of_max [sec] / ( Flashlight_mass_with_batteries [g] * (head diameter)2 [mm2] )
If you ask yourself what is ideal flashlight, you would quickly find out answer: ideal flashlight is extremely bright/extremely throwy for extremely long period of time, while its mass is close to zero, and dimensions/volume is very small.
Equations above are basically mathematical form of this "ideal flashlight" statement, and flashlight with higher calculated benchmark should be closer to "ideal flashlight".
Note that I put Run-time as time till max. initial output drops to 90% or lower (in case of thermal kick-down). This will prevent small lumen monsters to get too high scores because despite the high initial lumen output, run-time will be relatively small,so total score would be no better than some light with lower max. output but with longer run-time till <90%.