# Heat Management



## Bigwilly (Sep 28, 2015)

As light outputs keep going up and size keeps going down at some point better thermal management is going to be needed. Some of the modded lights only get a few minutes of runtime on their highest setting. I've searched but haven't found much of what is being done to help with thermal management. At the cutting edge, I would think active cooling would be on the horizon. I asked one well known modder and he told me active cooling and waterproofing don't mix yet. Are any manufacturers working on this? Any other ways for managing heat? I thought I saw a post where a member had a light that had a modded computer liquid cooling system in the light but it didn't go into much detail. Are there any other lights out there like this? I just see a light small enough for a belt holster that puts out 14k lumens but only for about 3 minutes and can't help but think if some kind of thermal management would increase it to say 20 minutes would make the light so much more usable.


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## more_vampires (Sep 29, 2015)

> I've searched but haven't found much of what is being done to help with thermal management.



Can't believe no replies yet. Let's get this heat party started.

Laser cooling:https://en.wikipedia.org/wiki/Laser_cooling


> All laser cooling techniques rely on the fact that when an object (usually an atom) absorbs and re-emits a photon (a particle of light) its momentum changes. The temperature of an ensemble of particles is larger for larger variance in the velocity distribution of the particles. Laser cooling techniques combine atomic spectroscopy with the aforementioned mechanical effect of light to compress the velocity distribution of an ensemble of particles, thereby cooling the particles.


A massive spread of science has opened up in the past few years concerning shining a laser on a substance that makes it cooler. Nothing's free, this puts the heat in the laser and not the thing being lased.

Thermoelectric Active cooling:https://en.wikipedia.org/wiki/Thermoelectric_cooling


> *Thermoelectric cooling* uses the Peltier effect to create a heat flux between the junction of two different types of materials. A Peltier cooler, heater, or thermoelectric heat pump is a solid-state active heat pump which transfers heat from one side of the device to the other, with consumption of electrical energy, depending on the direction of the current. Such an instrument is also called a Peltier device, Peltier heat pump, solid state refrigerator, or thermoelectric cooler (TEC). It can be used either for heating or for cooling,[1]​ although in practice the main application is cooling. It can also be used as a temperature controller that either heats or cools.[2]​



Heat pipe cooling:https://en.wikipedia.org/wiki/Heat_pipe


> A *heat pipe* is a heat-transfer device that combines the principles of both thermal conductivity and phase transition to efficiently manage the transfer of heat between two solid interfaces.
> 
> At the hot interface of a heat pipe a liquid in contact with a thermally conductive solid surface turns into a vapor by absorbing heat from that surface. The vapor then travels along the heat pipe to the cold interface and condenses back into a liquid - releasing the latent heat. The liquid then returns to the hot interface through either capillary action, centrifugal force, or gravity, and the cycle repeats. Due to the very high heat transfer coefficients for boiling and condensation, heat pipes are highly effective thermal conductors. The effective thermal conductivity varies with heat pipe length, and can approach 100 kW/(m⋅K) for long heat pipes, in comparison with approximately 0.4 kW/(m⋅K) for copper.





> At the cutting edge, I would think active cooling would be on the horizon.


Heh. The tech is there, just seems like nobody is using it ATM, AFAIK. With these techniques, it'll move the heat but you still have to sink it somehow once it gets there.



> I asked one well known modder and he told me active cooling and waterproofing don't mix yet.


People said that about liquid cooling a PC as well. All of the PC overclocking tricks apply, use 'em!
https://en.wikipedia.org/wiki/Computer_cooling#Piezoelectric_pump


> A "dual piezo cooling jet", patented by GE, uses vibrations to pump air through the device. The initial device is three millimeters thick and consists of two nickel discs that are connected on either side to a sliver of piezoelectric ceramics. An alternating current passed through the ceramic component causes it to expand and contract at up to 150 times per second so that the nickel discs act like a bellows. Contracted, the edges of the discs are pushed together and suck in hot air. Expanding brings the nickel discs together, expelling the air at high velocity.
> 
> The device has no bearings and does not require a motor. It is thinner and consumes less energy than typical fans. The jet can move the same amount of air as a cooling fan twice its size while consuming half as much electricity and at lower cost.[6]​


Oh, look at that. A fan with no real moving parts. How cool is that?



> Are any manufacturers working on this?


Yeah! *YOU* if you're interested. Liquid cooling kits here:
http://www.amazon.com/s?ie=UTF8&page=1&rh=i:aps,k:pc liquid cooling kits
http://www.xs-pc.com/watercooling-kits/
http://www.xoxide.com/watcoolkit.html



> Any other ways for managing heat?


Of course. You could just dunk it it a clear bucket of chilled baby oil and run it from there. We don't actually need a kit. CPFer Capolini did basically this trick with a snowbank one evening, bypassing a temperature sensor stepdown. The light did not step down.

Also, if you merely bonded a computer heat sink with fins to the head of the light, perhaps machining a flat spot and bonded the heat sink with something like Arctic Silver thermal epoxy, then this would accomplish two things:
1. Increase of thermal mass, extending possible runtime before stepdown.
2. Massive increase of surface area to dissapate that heat.
It wouldn't even have to be a big heat sink, this would massively help even without a fan and nothing's stopping you from adding one.

2 lions in series provides enough voltage to spin a computer 12v fan. They don't actually need a full 12v.

From my past of messing with computers, I discovered that a smooth heat sink is NOT what you want. The rougher the texture you can give the flashlight, you can almost double the surface area presented to the outside air. The more fins on the flashlight, the more surface area.

As a mechanic, I was amused to hear from a vehicle marque that polishing the engine voided the warranty as it cut the surface area for heat dissapation in half.

In short if you want better heat management, you don't necessarily have to get radical and crazy. A very rough textured flashlight is what you want, preferrably with a lot of cooling fins. A bead blast finish would be superior to the polished finish we typically see. The more knurling, the more surface area particularly when combined with bead blast. Also, the more thermal mass you add will extend the time before you should step it down.


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## more_vampires (Sep 29, 2015)

Kapow!!!!  Done editing. Time for a beer. :naughty:


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## Kestrel (Sep 29, 2015)

I found that the best way to avoid the thermal limiter on the OR/Torchlab V.4 XPG Triple was to take the flashlight on a walk in below-freezing temperatures. Could be a challenging solution in some regions though.


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## Bigwilly (Sep 29, 2015)

more_vampires said:


> Kapow!!!!  Done editing. Time for a beer. :naughty:



Pretty interesting reading. Now we gotta get Vinh onboard. Lol. Thanks for the insight. It's a bit to digest.


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## Bigwilly (Sep 29, 2015)

Kestrel said:


> I found that the best way to avoid the thermal limiter on the OR/Torchlab V.4 XPG Triple was to take the flashlight on a walk in below-freezing temperatures. Could be a challenging solution in some regions though.



I live in Maryland and the warmer months are hot. With Fall almost here and Winter around the corner I want to do some run times to see how much ambient temperature affects some lights. I suspect it makes a difference.


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## more_vampires (Sep 30, 2015)

Bigwilly said:


> Pretty interesting reading. Now we gotts get Vinh onboard. Lol. Thanks for the insight. It's a bit to digest.


The LD50VN Fiat Lux edition I got from him has additional thermal mass.

http://www.candlepowerforums.com/vb...er-anodizing-stripped-175-No-Longer-Available

Those copper plates have excellent thermal properties. Something like that but with grooves, fins, or fingers can only help in heat management.


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## Bigwilly (Sep 30, 2015)

more_vampires said:


> The LD50VN Fiat Lux edition I got from him has additional thermal mass.
> 
> http://www.candlepowerforums.com/vb...er-anodizing-stripped-175-No-Longer-Available
> 
> Those copper plates have excellent thermal properties. Something like that but with groves, fins, or fingers can only help in heat management.



Do you have any pictures. The link to panjo says the item is no longer available. I'm curious to see what it looks like. I get every option Vinh offers to manage heat. I learned the hard way as the first two lights I got from him didn't have the copper heat sink. Its well worth it I've learned.


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## more_vampires (Sep 30, 2015)

Bigwilly said:


> Do you have any pictures. The link to panjo says the item is no longer available. I'm curious to see what it looks like. I get every option Vinh offers to manage heat. I learned the hard way as the first two lights I got from him didn't have the copper heat sink. Its well worth it I've learned.


Scroll down in that link, there is a picture.

The LD50vn Fiat Lux has a copper sink plate on each flat of the head. Mine has V54 Fiat Lux on one side and "More Vampires" on the other. I will never sell it, ever.

Also: Vinh putting bonded copper plates in a pill.
http://www.candlepowerforums.com/vb/showthread.php?407539-TOOLvn-Best-IMR10440-Clicky-of-2015


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## Bigwilly (Sep 30, 2015)

more_vampires said:


> Scroll down in that link, there is a picture.
> 
> The LD50vn Fiat Lux has a copper sink plate on each flat of the head. Mine has V54 Fiat Lux on one side and "More Vampires" on the other. I will never sell it, ever.
> 
> ...



Gotcha. I totally missed it. I'm on tapatalk and it doesn't always fully load posts. Thanks. 
Does the copper plate get hot? It allow more runtime in your opinion.


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## more_vampires (Sep 30, 2015)

Warm, but not hot. I don't use it for long periods. I like throwing that warm dedome tight spot for long distance white wall hunting.

I agree with Vinh, that light didn't have enough mass for the current boost without them. Besides, it looks sexy.

I don't think I've ever used it "for real" past playing with it and demonstrating it. A non-flashy guy commented that it was beautiful.


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## Bigwilly (Sep 30, 2015)

more_vampires said:


> Warm, but not hot. I don't use it for long periods. I like throwing that warm dedome tight spot for long distance white wall hunting.
> 
> I agree with Vinh, that light didn't have enough mass for the current boost without them. Besides, it looks sexy.
> 
> I don't think I've ever used it "for real" past playing with it and demonstrating it. A non-flashy guy commented that it was beautiful.



Very cool. I also like it's personalized.


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## Bigwilly (Oct 2, 2015)

Anybody have any pictures or links to lights using active cooling of some form?


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## more_vampires (Oct 2, 2015)

Bigwilly said:


> Anybody have any pictures or links to lights using active cooling of some form?


LOL! http://www.printglobe.com/hand-fans...ry-and-misting-fans/turbo-mini-fan-flashlight

Seriously though, Lux-RC was working on that.http://lux-rc.com/content/products/flashlights/FB1_fat_boy/insider_files/

*http://www.ledsmagazine.com/article...st-lumen-output-in-led-lighting-magazine.html

http://www.candlepowerforums.com/vb/showthread.php?391532-Active-cooling-in-lights

[url]http://www.candlepowerforums.com/vb/showthread.php?398630-XHP70-crude-test
[/URL]
*


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## drmaxx (Oct 2, 2015)

Didn't we just had this discussion a few weeks ago?

Edit: I just realise that more_vampires actually found the link to the thread I was thinking about. 
Move along - nothing to see here:wave:


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## more_vampires (Oct 2, 2015)

drmaxx said:


> Didn't we just had this discussion a few weeks ago?
> 
> Edit: I just realise that more_vampires actually found the link to the thread I was thinking about.
> Move along - nothing to see here:wave:









So? I like this thread better!  Active Cooling thread was so 2014. This is 2015. 

Nobody other than a hobbyist has ever made a flashlight with this:




It's a heat sink with phase change heat pipe plus radiator. Add a fan and now you're moving some serious heat.


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## more_vampires (Oct 2, 2015)

http://www.lunaraccents.com/educational-LED-thermal-management.html


> As the LED heat escalates, several key characteristics may become apparent, which deminstrate the importance of LED thermal mangament. The forward voltage will begin to decrease. The decreasing voltage can impose an increased load on related LED driver components causing their temperature to increase as well. In resistor driven circuits, the forward current will increase. As the LED lights temperature continues to rise, the optical wavelength can shift. The increasing wavelength can cause orange LED lights to appear red or even white LED lights to appear bluish. This color shift typically intensifies with the AlInGaP technologies (red, orange, amber, and yellow). In addition, a thermally stressed LED lights will loose efficiency and light output will diminish. If the LED thermal management continues to race out of control, the LED junction may break down causing a state of complete thermal runaway. The result is typically catastrophic failure. Other affects of overstressed LEDs may include broken wire bonds, delaminating, internal solder joint detachment, damage to die-bond epoxy, and lens yellowing.



Sinking a Maglite: http://www.instructables.com/id/LED...tion/step4/Heat-Sink-and-Copper-Pipe-Fitting/

Thermal management of high power led: https://en.wikipedia.org/wiki/Thermal_management_of_high-power_LEDs

Led cooling design: http://www.qats.com/cms/free-thermal-management-led-lighting-resource-kit/

Calculating heat sinks: http://www.led-heatsink.com/LED_heat_sink_calculation_simulation_thermal_design.html

A whole lot of heat sinks: http://led-heatsink.com/

Casting heat sinks: http://www.mechanicalengineeringblog.com/tag/led-heat-sink/

Modding and heat sinking with Jayrob: http://laserpointerforums.com/f64/fs-mxdl-host-heatsink-combo-4171-3405-a-22512.html

Liquid cold plates: http://www.thermacore.com/products/cold-plates.aspx

A bunch of articles on LED heat: http://www.led-professional.com/products/led-thermal-management

We've just scratched the surface of heat management. This thread is not done by a long shot.


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## Bigwilly (Oct 2, 2015)

more_vampires said:


> So? I like this thread better!  Active Cooling thread was so 2014. This is 2015.
> 
> Nobody other than a hobbyist has ever made a flashlight with this:
> 
> ...



You Sir are my new best friend. LOL. Seriously, I now have a bunch of reading material and I really appreciate it.


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## more_vampires (Oct 2, 2015)

:thumbsupthumbsup:

I used to be a resident at Answers.com. I've always enjoyed doing this sort of thing.


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## Midnight.Sun (Oct 2, 2015)

Bigwilly said:


> Are any manufacturers working on this? Any other ways for managing heat? I thought I saw a post where a member had a light that had a modded computer liquid cooling system in the light but it didn't go into much detail. Are there any other lights out there like this? ...



I remember this HID flashlight had catched my eye a year ago in a Microfire catalog :

http://www.microfire-system.com/FlieDownload.aspx?Url=635276439152300920.pdf

"Microfire Saucy 50 W HID" (read feature nm -6-)

















Don't know if it has ever been produced, never seen it anywhere, its not listed in the 2015 edition unfortunately.
Very beautiful big HID light, actually i'v had the best dreams about its throw performance .


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## more_vampires (Oct 2, 2015)

Microfire has some interesting products. Too bad they seem rather hard to get in the US.

I had my eye on their "Teeth of Tiger" model, CPFer Gopajti turned me on to it. Haven't found one to buy yet though. I refuse to eBay, there's two listed there at the moment.

Edit: Optics Planet! Wheeeeeeeeeeeeeeeeeee! 

The Teeth of Tiger model looks like it'd have good heat management as there is quite a bit of additional mass in the sliding tiger tube.

On order now! :devil: Can't talk much about this light on CPF. There's policy against that.


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## Midnight.Sun (Oct 2, 2015)

I edited my previous post, added a clearer more easy to read pic of the features, and a link of the catalog.


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## Bigwilly (Oct 2, 2015)

more_vampires said:


> Microfire has some interesting products. Too bad they seem rather hard to get in the US.
> 
> I had my eye on their "Teeth of Tiger" model, CPFer Gopajti turned me on to it. Haven't found one to buy yet though. I refuse to eBay, there's two listed there at the moment.
> 
> ...



Can you pm me a link and some more info
Searched on opticsplanet and couldn't be it.


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## Bigwilly (Oct 2, 2015)

Midnight.Sun said:


> I remember this HID flashlight had catched my eye a year ago in a Microfire catalog :
> 
> http://www.microfire-system.com/FlieDownload.aspx?Url=635276439152300920.pdf
> 
> ...



Thank you for the info. I'm catching up on a lot of info from you guys. Keep it coming.


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## Midnight.Sun (Oct 2, 2015)

Bigwilly said:


> Thank you for the info. I'm catching up on a lot of info from you guys. Keep it coming.



Welcome ..


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## Midnight.Sun (Oct 2, 2015)

more_vampires said:


> Microfire has some interesting products. Too bad they seem rather hard to get in the US.
> 
> I had my eye on their "Teeth of Tiger" model, CPFer Gopajti turned me on to it. Haven't found one to buy yet though. I refuse to eBay, there's two listed there at the moment.
> 
> ...



Do you consider Amazon a bad source for flashlight shopping as well ? Why is that ? what's your theory about it ?

Nice catch .. ":devil:" indeed, its pic says it all.


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## Bigwilly (Oct 2, 2015)

Midnight.Sun said:


> Do you consider Amazon a bad source for flashlight shopping as well ? Why is that ? what's your theory about it ?
> 
> Nice catch .. ":devil:" indeed, its pic says it all.



I buy from Amazon all the time. The only new light that was stock I got from them. But only cause there's no V54 Latern..... yet hopefully. As long as you get from a reputable place you're good. ie I'm a prime member and pretty much only buy prime items. The photographers backpack I got was an Amazon Basic. I think like 25.00 A week later the professional wedding photographer has the exact bag but the rubber pulls on the zipper say Nikon. He paid like 125.00 for it. YMMV


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## Rick NJ (Oct 2, 2015)

Hey, JohnDoe, what is in the push cart you are pushing around?

Oh, the bottom shelf has the battery to run my pocket flashlight and the two fists like thing are actually jumper cables clips. The top shelf has the radiator plus the radiator-fan battery. This long fish tank air hose like thing connects to this outlet in my pocket flashlight to cool it, and I clip the jumper cables to here on my pocket flashlight. Wait, wait, let me hook it up to show you how bright this tiny itty-bitty pocket flashlight is!


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## Midnight.Sun (Oct 2, 2015)

Bigwilly said:


> I buy from Amazon all the time. The only new light that was stock I got from them. But only cause there's no V54 Latern..... yet hopefully. As long as you get from a reputable place you're good. ie I'm a prime member and pretty much only buy prime items. The photographers backpack I got was an Amazon Basic. I think like 25.00 A week later the professional wedding photographer has the exact bag but the rubber pulls on the zipper say Nikon. He paid like 125.00 for it. YMMV



I got my Thrunite TN35 from amazon.de direct Amazon Thrunite store, the light arrived clean as a whistle inside its aluminium case, but the control ring and stainless steel bezel had quality issues, i'm sure its Thrunite's fault they allowed quality differences throughout different batches, as almost all other Thrunite TN35 pics or reviews on the web didn't have Any of those issues, so when "MoreVampire" mentioned that he never buys flashlights from Ebay, he reminded me of that, as I always thought that telling my source to get it from Amazon was a mistake, but I doubt that as i think Amazon's Thrunite store is the official place to get Thrunite flashlights in Germany, it's probably just a batch quality lottery.


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## Midnight.Sun (Oct 2, 2015)

Rick NJ said:


> Hey, JohnDoe, what is in the push cart you are pushing around?
> 
> Oh, the bottom shelf has the battery to run my pocket flashlight and the two fists like thing are actually jumper cables clips. The top shelf has the radiator plus the radiator-fan battery. This long fish tank air hose like thing connects to this outlet in my pocket flashlight to cool it, and I clip the jumper cables to here on my pocket flashlight. Wait, wait, let me hook it up to show you how bright this tiny itty-bitty pocket flashlight is!



:laughing::laughing::laughing::laughing::laughing: Yeah good one..... but HID SpotLight Search Lights have their high place in the flash light world, the more bulky the more manly, you can't emagin a perfect search and rescue scenario to be held with less than one, and that Saucy K5000R is by far the most beautiful HID i have ever seen :naughty: , i'd love to add it to my flashlight collection one day, if i can afford.. and the feeling of the little fan inside of it cooling it down is just ,,,,,,,,,,,, ,,,,,,,,,,,,craaaaaaaaaaaaaaaazy


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## Bigwilly (Oct 2, 2015)

I wonder if the invisible fan would fit in the X60vn???


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## Midnight.Sun (Oct 2, 2015)

Highly doubtful maybe impossible , but the hekk.. Why not to ask !! A special order maybe, poor Vinh :hairpull: ..


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## Bigwilly (Oct 2, 2015)

Midnight.Sun said:


> Highly doubtful maybe impossible , but the hekk.. Why not to ask !! A special order maybe, poor Vinh :hairpull: ..



I'm first in line. Just sayin


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## Midnight.Sun (Oct 2, 2015)

Bigwilly said:


> I'm first in line. Just sayin



Sorry.. you got me wrong, actually my English is not very sharp, somtimes my writing might sound like something I didn't intend to say.

What i meant to tell you is that i think the fan idea is probably impossible inside the X60vn, but what do i know, why don't you ask Vinh, as I assumed you have contact with him, cuz you said earlier that all your lights are custom.

Besides it is your idea, you should have the rights of suggest it


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## Bigwilly (Oct 2, 2015)

Midnight.Sun said:


> Sorry.. you got me wrong, actually my English is not very sharp, somtimes my writing might sound like something I didn't intend to say.
> 
> What i meant to tell you is that i think the fan idea is probably impossible inside the X60vn, but what do i know, why don't you ask Vinh, as I assumed you have contact with him, cuz you said earlier that all your lights are custom.
> 
> Besides it is your idea, you should have the rights of suggest it


No I'm sorry. My intention was just be funny. Your English is pretty good. What is your primary language?


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## Midnight.Sun (Oct 3, 2015)

* future readers:
"This post is off topic and not flashlight related. It is a chronicle about Syria and the difficult war it was going through, this also applies to the addendum post next and that's all, thanks for understanding." Midnight.Sun



Bigwilly said:


> No I'm sorry. My intention was just be funny. Your English is pretty good. What is your primary language?



Me too was trying to sound a little funny, that's what got me into some English Grammar weaknesses 

I live in Syria (my beloved historic homeland) and as you may have heard we are having it all, a local and regional and global armed conflict on our soil, we are also living under US and global sanctions the recent years, so there is no direct postal or credit card service available for the time being, thats why I can't send my lights for modding, i had trouble getting the very few I got into the country the first place, so obviously i have no contacts with any of the modders, but i like my stock versions so much. I am also relatively new here, but have been interested in flashlights since childhood.

As a Secularist in life and a Christian in birth in Syria my primary "original" language should have been Assyrian Aramaic the spoken language of Jesus Christ who lived in about 200 miles to the south of our city 2000 years ago, or it should have been at least some sort of Byzantine language from the Byzantine Empire Era, but no! It is Arabic and Arabic alone, why? That's because of the Arabic Islamic invasion that happened 1400 years ago, whom have a habit of clearing the lands they occupy from its original cultures, through either direct or indirect persecution methods especially under the Turkish Ottoman Occupation era, although the Aramaic, Chaldean, Kurdish, Arminian ..etc of ancient Syrian languages does still exists in some parts of Syria and Middle East to this day.

And now history is repeating itself all over again, more fiercely this time by the "Jihadi Salafis Terrorists" (the students of Wahhabi movement in Saudi Arabia that is supporting them), and by the armed groups of "Muslim Brotherhood Movement" which is ruling Turkey legally and openly by the name of "Justice and Development Party" and also ruling the state of Qatar behind the scenes as well, all of them Sudi Arabia, Turkey, Qatar by using the extremists among the Syrian Sunnies and foreigner Jihadi Terrorists, they want to change Syria into a full Islamic Shariaa State worse than it was before WW1 when the Turkish Ottomans where defeated by the allies back then (Russia, Britain, and France) who drove the Turks out of our region (Middle East). 
But we've been fighting back for four years now, and today we are fighting alongside with our allies, Russia, Iran, and the Lebanese Resistance, and coordination with some Arab States like Lebanon, Iraq, Algeria, Egypt and others, and support of China and our friends nations in South America and others all over the world.

I know that there is still tons of details that i have not mentioned but i think i hit the most important ones, yes I know many people (Syrian citizens) took out to the streets screaming for "freedom", but the vast majority of them mixed it with the screams of "Allah Akbar" from the very first day, which was their real inner intention, and yes the government is not democratic and was anything but patient to its opposition, i know that very well because i am one, i have been looking forward for democratic reforms my hall life, since the 80's and 90's at school and college, when students had to wear military uniform daily and have three military classes a week, under full discipline all the time, military weekends and summer camps at college (those procedures ended at 2003 if I remember correctly), but back then a lot of those who are dying today by the minute for the sake of Islam were not born yet, and never seen any real dictatorship, long before this 2011 Islamic Spring yes i was one but not anymore, i'm not interested in democracy in this region anymore, it turned out that we were living a lie, and the truth is that our nations in the Middle East can't stand democracy and freedom at all, because Islam is the opposite of all that, they are still far from even accepting the being of each other, and will keep on killing each other on religious bases for years to come.

Not the usual one word answer for your question I know, so in other words it is "Arabic" my secondary language, my primary language i don't even know one shape of one letter of it.

* Actually i ended up editing a lot more than two spelling typos, and if i have crossed a line i can understand any supervision action to be taken, as this hall thing was off topic.


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## Bigwilly (Oct 3, 2015)

Midnight.Sun said:


> Me too was trying to sound a little funny (CPFers kind of style) thats what got me into some English Grammar weaknesses
> 
> I live in Syria (my beloved historic country) -as you may have heard- we are having Local, Regional and Global Armed Conflict, and we live under US and Global sanctions the recent years, si there is no direct postal or credit card service available for the time being, thats why I can't send my lights for modding, i had trouble getting the very few I got into the country the first place, so obviously no contacts with modders, i'm also new here, but been a Flashlightaholic since childhood.
> 
> ...



I have no doubt that your homeland is beautiful and has a wonderful history. I'm sorry that there is a conflict going on. 
Hopefully it's resolved and the sanctions are lifted and you are free to purchase whatever you like.


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## Midnight.Sun (Oct 3, 2015)

Bigwilly said:


> I have no doubt that your homeland is beautiful and has a wonderful history. I'm sorry that there is a conflict going on.
> Hopefully it's resolved and the sanctions are lifted and you are free to purchase whatever you like.



Thanks man


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## Rick NJ (Oct 3, 2015)

Midnight.Sun said:


> ...I live in Syria (my beloved historic country)...



Welcome and glad to have your acquaintance. Here, we love everybody, but we really don't like those without adequate lumens. We judge fellow men not by the batteries they carry, but by the amperage they can deliver.

On a more serious note, hope all is well with you, and have a safe day.


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## Bigwilly (Oct 3, 2015)

Rick NJ said:


> Welcome and glad to have your acquaintance. Here, we love everybody, but we really don't like those without adequate lumens. We judge fellow men not by the batteries they carry, but by the amperage they can deliver.
> 
> On a more serious note, hope all is well with you, and have a safe day.



Well said.


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## bykfixer (Oct 4, 2015)

That comment by midnight sun shows how good we have it where ever we are. 
Yet it also shows how fragile freedom is. 

And may your beautiful homeland be free from conflict soon Mr. Sun

I honestly believe after see-ing cel phones go from a big ole bag that was good for maybe...20 minutes, to a shoe sized portable, then slowly evolve into a pocket sized home computer...that efficiency of power useage is the future. 

Until then maybe some of those cool wrap swelling reducer bands over top of a cloth wrapped around a hi power light would be good.


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## Midnight.Sun (Oct 4, 2015)

* addendum post (off topic, not flashlight related)

Sorry for the late response 

Thanks for the kind wishes guys "BykFixer - BigWilly - Rick NJ" my best wishes to you all and to every one here in CPF.

Mr. Rick .. I won't reveal my hall arsenal but I would say its ~ 10000 lm combined, and that is only the start 

As for my self i am well and relatively very safe like most of the citizens who live in the cities and towns under government control (including the displaced refugees), we are the ones who insisted on staying in the country and did not trust the outside-based fake opposition that was only a cover up for bigger foreign affairs, my city before the crisis used to hold near 150000 citizens, now it is holding many times multiple that number. Inside our city life is almost normal, but ofcourse there are some military check points and patrols, a lot of daily timeline electric blackouts (flashlight heaven) but seriously it is very depressing it ranges between 8 in normal days to 16 hours at the peak days of summer and winter, national currency lost a lot of its value so everything feels insanely high priced, UN aids for the needed displaced citizens, but we are used to all this now, what's important is the country gets through the hall dam thing.

Yes the only two cities and some small towns and countrysides that are under Sunni Islamic Armed Groups (Salafis Jihadist and Muslim Brotherhoods) like ISIS, Al Nusra Front, Islam Army, Jaish al Fateh, ...etc, they do face a lot of daily military actions and civil war, but the worst of all is that the citizens there are living under various degrees of cruel inhuman Islamic Shariaa laws which was the real intention behind the Sunni uprising.

P.S. There is a spelling mistakes in my earlier post which can effect the meaning a little, i typed the word "prosecution" instead of "persecution" , and i also typed "flashlightaholic since childhood" but what i mean is "interested in flashlights since childhood" as flashlightaholic children are yet to exist. I'll edit and correct.

* I ended up editing a lot more than two typos, in this post and the previous, couldn't help the stir of thoughts.


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## bykfixer (Oct 5, 2015)

Your English and typing skills excel many life long Americans.

Hopefully no blackouts occured while you were editing.


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## Midnight.Sun (Oct 5, 2015)

A lot of blackouts, falling asleep, and internet difficulties, i lost a lot of writings and had to do it again many times, i wonder about the CPF posting mechanisem!! When it comes to handling large letters, or the problem is probably my IPod Touch 5 weak processor.


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## bykfixer (Oct 5, 2015)

Dealing with Windows OS all these years, I've learned to hit save every few minutes. 
It severely interupts your train of thought in many cases, but beats starting over.


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## Midnight.Sun (Oct 5, 2015)

I'm using phone IOS Safari, and the screen kept on freezing more and more with the text expanding, and it seems that it won't keep me signed in for long, one time i lost most perfect post completely, because when the text is large its hard to open the thing that allows you to press COPY, there i decided to give up the hall thing, but I felt that i had obligations to finish those thoughts once and for all, so i rewrote the hall thing from the start.

By the way CPF we can't write on the Note App and copy into here, symbols and numbers spread all over the hall thing, and its very hard to delete them, but i think it's a good thing to encourage us to write online, it helps keep the originality of stuff :thumbsup: , maybe! IDK.


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## Bigwilly (Oct 5, 2015)

Midnight.Sun said:


> I'm using phone IOS Safari, and the screen kept on freezing more and more with the text expanding, and it seems that it won't keep me signed in for long, one time i lost most perfect post completely, because when the text is large its hard to open the thing that allows you to press COPY, there i decided to give up the hall thing, but I felt that i had obligations to finish those thoughts once and for all, so i rewrote the hall thing from the start.
> 
> By the way CPF we can't write on the Note App and copy into here, symbols and numbers spread all over the hall thing, and its very hard to delete them, but i think it's a good thing to encourage us to write online, it helps keep the originality of stuff :thumbsup: , maybe! IDK.



I feel ya. I am doing a thorough review on the M30Cvn using the Tapatalk app on tablet and its a pain I cant use an app for writing and then copy it over into the Tapatalk app. Ohh well. It could always be worse.


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## more_vampires (Oct 5, 2015)

Bigwilly said:


> Can you pm me a link and some more info
> Searched on opticsplanet and couldn't be it.


Microfire changed the name for American release. It's now the "PHL-2r Spike." I kind of liked the old name. Oh well. 



Midnight.Sun said:


> Do you consider Amazon a bad source for flashlight shopping as well ? Why is that ? what's your theory about it ?
> 
> Nice catch .. ":devil:" indeed, its pic says it all.



I think that light just plain looks flat out cool with the bezel extended. That light could possibly be current boosted pretty high with all that extra mass. It's an anemic 130lm stock. Absolutely SCREAMING for a current boost mod. That light has a lot of potential. Might send it to Vinh and see what he can do? Why not? They are already expensive, let's make it more so! 

As far as that "Saucy 55w HID," what the heck is an invisible fan? Where's the intake and exhaust? Waterproof?

I think we need a few more details on that light, sounds intriguing.

Anyway, I got burned on eBay a couple times so I swore off of it. I shy away from Amazon, but will buy from that organization if there's no choice. I certainly refuse to Amazon and eBay for the rock bottom price on batteries as that's an excellent way to get saddled with a counterfeit.


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## MAD777 (Oct 5, 2015)

Just a comment to on writing reviews outside of Tapatalk and then copying it over. There's no problem at all doing this on Android platforms. That's one of the many reason I left Apple behind.


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## more_vampires (Oct 5, 2015)

Let's get back on topic, guys.

I have 4 of these P60 heads:
http://www.cryosillumination.com/bezel/

Specifically, their M2 model.

Copper easily beats aluminum in thermal properties. Both of them crush the various brass alloys.

https://en.wikipedia.org/wiki/Heat_capacity


> *Heat capacity* or *thermal capacity* is a measurable physical quantity equal to the ratio of the heat added to (or removed from) an object to the resulting temperature change.[1]​ The SI unit of heat capacity is joule per kelvin
> 
> 
> 
> ...



https://en.wikipedia.org/wiki/Heat_capacity#Table_of_specific_heat_capacities
Check out this table of heat capacities of different materials. Capacity is one property, but good thermal conduction is more important.

https://en.wikipedia.org/wiki/Thermal_conductivity


> In physics, *thermal conductivity* (often denoted _k_, _λ_, or _κ_) is the property of a material to conduct heat. It is evaluated primarily in terms of Fourier's Law for heat conduction.
> 
> Heat transfer occurs at a lower rate across materials of low thermal conductivity than across materials of high thermal conductivity. Correspondingly, materials of high thermal conductivity are widely used in heat sink applications and materials of low thermal conductivity are used as thermal insulation. The thermal conductivity of a material may depend on temperature. The reciprocal of thermal conductivity is called thermal resistivity.
> Thermal conductivity is actually a tensor, which means it is possible to have different values in different directions. See #Thermal anisotropy below.


For best heat management, you don't want to thermally insulate. You don't want air gaps, you want tight bonding between the pill of the flashlight and the head. Like in PC CPU heat sinks, there is a specification for minimum pressure to ensure a good thermal junction.

https://en.wikipedia.org/wiki/Thermal_conductivity#Conductance


> For general scientific use, _thermal conductance_ is the quantity of heat that passes in unit time through a plate of _particular area and thickness_ when its opposite faces differ in temperature by one kelvin. For a plate of thermal conductivity _k_, area _A_ and thickness _L_, the conductance calculated is _kA/L_, measured in W·K−1​ (equivalent to: W/°C). The thermal conductance of that particular construction is the inverse of the thermal resistance. Thermal conductivity and conductance are analogous to electrical conductivity (A·m−1​·V−1​) and electrical conductance (A·V−1​).



So thermal conductance is quite a lot like electronics, really.

Anyway, when installing a P60 dropin into a P60 head, often there is an air gap and the dropin is mostly not touching the head. This gives poor heat management. Shim the module with copper or aluminum foil for a tight fit. Now you're moving heat more efficiently.


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## Rick NJ (Oct 5, 2015)

Midnight.Sun said:


> Sorry for the late response
> Mr. Rick .. I won't reveal my hall arsenal but I would say its ~ 10000 lm combined, and that is only the start


Ahem... You can take my seat. I think I best move to the back of the bus with my 1000lm combined...

I think we now need a new unit - SLM for seller's listed lumens. 2000slm sounds so much better than the 200lm I estimated the light at.


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## more_vampires (Oct 5, 2015)

Rick NJ said:


> Ahem... You can take my seat. I think I best move to the back of the bus with my 1000lm combined...
> 
> I think we now need a new unit - SLM for seller's listed lumens. 2000slm sounds so much better than the 200lm I estimated the light at.


We refer to those as "China Lumens." They are not based on reality.


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## Bigwilly (Oct 5, 2015)

more_vampires said:


> Let's get back on topic, guys.
> 
> I have 4 of these P60 heads:
> http://www.cryosillumination.com/bezel/
> ...


You are a wealth of knowledge. I am almost done checking all those links you provided me so thanks. Do you know of a way to make say, the X60vn have better thermal management? Any mods you would do yourself? It already has Vinh's copper heatsink.


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## more_vampires (Oct 5, 2015)

Bigwilly said:


> You are a wealth of knowledge. I am almost done checking all those links you provided me so thanks. Do you know of a way to make say, the X60vn have better thermal management? Any mods you would do yourself? It already has Vinh's copper heatsink.


Thanks, I was blessed with a strong science background. It wasn't free, lots of work. I don't know everything, life is a journey. I want to know as much as I can before my time comes to exit this world, stage right.

Vinh usually has his thermal management tighter than a drum. He straightens out some stuff pretty wonky from the factory. To get better than Vinh, usually you're going to have to completely remake the host body (or at least the head) in a better material, such as copper. This is no longer a mod but a full build.

1. Thermal properties of the metal
2. Good thermal junction with a tightly screwed pill or a heat-interference press-fit pill. This leads to good thermal path
3. Good surface area for heat dissipation
4. As little dead-air space inside the light head as possible. Air pockets are insulators and reduce the surface area contact, impeding heat transfer.
5. Any auxiliary cooling active cooling methods mentioned thus far in the thread.

http://www.heatsink-guide.com/content.php?content=heatsinkinfo.shtml
On the topic of a good thermal junction, PC heat sink "thermal paste" such as Artic Silver thermal grease will give better heat transfer, but the surfaces need to be a tight fit. Gobs of thermal paste aren't good for transfer.


> Years ago, when CPU hat power dissipations around 10 watts, a thermal interface material was optional, and most often used by overclockers to improve cooling performance. With todays CPUs, it is an absolute requirement.



Seen the Oveready Triple Wasp? It has holes in the head for added airflow.
http://www.candlepowerforums.com/vb...olar-Triple-Wasp-Cooling-Head-and-Glow-System
Pretty spiffy. This also massively increases surface area for heat path.


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## Midnight.Sun (Oct 5, 2015)

Rick NJ said:


> Ahem... You can take my seat. I think I best move to the back of the bus with my 1000lm combined...
> 
> I think we now need a new unit - SLM for seller's listed lumens. 2000slm sounds so much better than the 200lm I estimated the light at.





more_vampires said:


> We refer to those as "China Lumens." They are not based on reality.



I used SELM for Selfbuilt Estimated Lumens, well i said ~ 10000 in fact they are 1 (MT-G2) max output + 3 (XM-L2 U2) + 1 (XM-L2 T6) , one of the XML U2 driven to 1700 lm  , so you can say close to the revealed Lumens, but as you can figure out from my high end LEDs, i'm very new to the real flashlight world, i got them all only last year (two purchases), so my seat is definitely in the back of the bus too, cuz before that i packed only like ~ 100 lumens combined at best, with the strongest in order was a Mini Mag crome colour with claimed 85 lm, Panasonic incandescent 2 D, and a lot of Varta LEDs AA/AAA, lots of GP LEDs AAA, lots of Go Design LEDs AAA (duty free for travelers stuff) rest were a lot of dead incandescents and LEDs which don't have a real brand name.

But my most important light and the greatest i ever laid my hands on was back in the 80's when i was a child, an old red Chinese incandescent spotlight 8 D cells = 12V (metal box style) with a big ~ 8cm - 10 cm head diameter (motorcycle crome head style) on the shelf at my grandparents house, but couldn't convince anyone to buy me 8 D batteries to see it lighted :mecry:, and unfortunately it was considered unneeded and was sold in haste along with every thing else when the house had to be demolished .

* I searched a little and found a picture of similar one but not the exact same, ours had a black plastic handle with smal white button at its front, and the head was attached to the red metal box with stainless steel arc and screws.


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## Bigwilly (Oct 5, 2015)

more_vampires said:


> Thanks, I was blessed with a strong science background. It wasn't free, lots of work. I don't know everything, life is a journey. I want to know as much as I can before my time comes to exit this world, stage right.
> 
> Vinh usually has his thermal management tighter than a drum. He straightens out some stuff pretty wonky from the factory. To get better than Vinh, usually you're going to have to completely remake the host body (or at least the head) in a better material, such as copper. This is no longer a mod but a full build.
> 
> ...



I really thought you were gonna tell me this. Everything from Vinh has been well thought out and well executed. Just think for me, the TK75vnQ would be a perfect light and the X60vn close behind it, if they could run on high for 15+ minutes. But you can't defeat physics. 
Thank you again for your insightful replies.


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## more_vampires (Oct 5, 2015)

Quite welcome, friend. I'm still trying to source the spongy thermal cubes he uses to fill voids, but he's been swamped with business and got sick. Hasn't gotten back to me yet.


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## Bigwilly (Oct 5, 2015)

more_vampires said:


> Quite welcome, friend. I'm still trying to source the spongy thermal cubes he uses to fill voids, but he's been swamped with business and got sick. Hasn't gotten back to me yet.



You know what? He told me that the X60vn could take the thermal pads but they are to help cool the driver so I don't know that it would increase run times.


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## more_vampires (Oct 5, 2015)

Circuit efficiency has a tendency to decrease as heat rises. Ensuring proper thermal path for the driver itself would no doubt help. It might take lab equipment to tell the difference, but I've no doubt that there would be some positive.

Keep in mind that in really overdriven lights, the solder turns to liquid and if you drop one of them while hot it can easily kill the light. 

If your driver is overdrive and has no thermal path of its own except the edges of the circuit board (circuit boards themselves don't really conduct heat,) then the overdrive is limited as you'll cook the driver in 2 minutes of runtime. Drivers in many lights are stuck in an air pocket and this is a limiting factor in the drive strength of a great many lights.

This is why when you drop a 10440 lion into an AAA light that doesn't fry but gets super bright, that you really should limit the runtims to bursts less than 2 minutes.

The Streamlight Microstream AAAx1 comes to mine. I've two of them, they light with 10440 but get mega hot in seconds. SL changed the design and you pretty much can't crack them open to do thermal modding. Oh well. There's other hosts.

Keeping the light bursts short is also a form of thermal management.


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## Midnight.Sun (Oct 5, 2015)

Qustion: if one was in snowy weather and say wondering out at night with a light like Bigwilli's TK75vnQ or X60vn , and dipped it in the snow every now and then, is that a good thermal practical strategy ? Or stupid thinking that will end up with broken lense or aluminium host ? I lean to the first.


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## Bigwilly (Oct 5, 2015)

more_vampires said:


> Circuit efficiency has a tendency to decrease as heat rises. Ensuring proper thermal path for the driver itself would no doubt help. It might take lab equipment to tell the difference, but I've no doubt that there would be some positive.
> 
> Keep in mind that in really overdriven lights, the solder turns to liquid and if you drop one of them while hot it can easily kill the light.
> 
> If your driver is overdrive and has no thermal path of its own except the edges of the circuit board (circuit boards themselves don't really conduct heat,) then the overdrive is limited as you'll cook the driver in 2 minutes. Drivers in many lights are stuck in an air pocket and this is a limiting factor in the drive strength of a great many lights.



I've taken the X60vn till it's pretty damn hot it still worked. So I backed a bit off of that. ie I've taken it to over 8 minutes on a 88 degree evening. So I keep it under 6 minutes before backing off.


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## Bigwilly (Oct 5, 2015)

Midnight.Sun said:


> Qustion: if one was in snowy weather and say wondering out at night with a light like Bigwilli's TK75vnQ or X60vn , and dipped it in the snow every now and then, is that a good thermal practicality ? Or just stupid thinking that will end up with exploded aluminium host ? I lean to the first.



Someone posted recently but I can't find it that one prominent member did just that to keep the light from thermally stepping down. I don't believe it would cause a problem but others (ahem cough more_vampires)with more knowledge should be along shortly.


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## Midnight.Sun (Oct 5, 2015)

Ahem.. more-vampires is a brain boooster for sure, im trying to keep up, said trying, ahem..


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## more_vampires (Oct 5, 2015)

Midnight.Sun said:


> Qustion: if one was in snowy weather and say wondering out at night with a light like Bigwilli's TK75vnQ or X60vn , and dipped it in the snow every now and then, is that a good thermal practicality ? Or just stupid thinking that will end up with exploded aluminium host ? I lean to the first.


It won't cause any problems, provided that the light is well sealed and water proof. If you dipped a hot light into something extremely cold, such as a cryogenic liquid (liquid helium, etc) then there will be "thermal shock," and something's going to shatter. Snow is unlikely to do this as it contains as much as 90% air by volume. Trapped air is a thermal insulator and will limit the rate of thermal transfer and mitigate the risk of thermal shock. Throwing a red hot overdrive light into 35F degree water very may well trigger cracking and such due to thermal shock.

Alternatively, if you started the light off in the water then the temperature gradient would be less, thus less thermal shock.

https://en.wikipedia.org/wiki/Thermal_shock


> *Thermal shock* occurs when a thermal gradient causes different parts of an object to expand by different amounts. This differential expansion can be understood in terms of stress or of strain, equivalently. At some point, this stress can exceed the strength of the material, causing a crack to form. If nothing stops this crack from propagating through the material, it will cause the object's structure to fail.
> 
> Failure due to thermal shock can be prevented by;
> 
> ...


https://en.wikipedia.org/wiki/Thermal_shock#Examples_of_thermal_shock_failure

Whether or not thermal stepdown will change anything is based on 1 thing:
Temperature sensor step down or timer based step down.

Not all lights even HAVE a step down of any kind, max is max and that's it. For the ones that step down the output after a certain time or temperature, the highest mode would actually be referred to as TURBO, since you don't get to keep it that way until the batteries run down. For a light to maintain 100% full output at the same level for the run of the battery is referred to as "Flat runtime, 100% duty cycle." In a light like that, there's no point to keeping burst short unless you're trying to save some battery for later.

On a temperature sensor stepdown light, shoving the light into snow once in a while will bypass the stepdown. This has been verified numerous times in the V54 subforum. IIRC, last poster who mentioned it was CPFer Capolini. (Who has been MIA for a while, miss him. He's cool.)

In Vinh lights with the DriverVN2 and VNX, it's a timer based stepdown. You can adjust it manually. To totally disable it must be done by Vinh and now you are on your own. If the light comes on in your suitcase, there could be problems.

Maybe VN3 will have temp sensor step down, who knows? We're not there yet.


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## Bigwilly (Oct 5, 2015)

more_vampires said:


> It won't cause any problems, provided that the light is well sealed and water proof. If you dipped a hot light into something extremely cold, such as a cryogenic liquid (liquid helium, etc) then there will be "thermal shock," and something's going to shatter. Snow is unlikely to do this as it contains as much as 90% air by volume. Trapped air is a thermal insulator and will limit the rate of thermal transfer and mitigate the risk of thermal shock. Throwing a red hot overdrive light into 35F degree water very may well trigger cracking and such due to thermal shock.
> 
> https://en.wikipedia.org/wiki/Thermal_shock
> 
> ...



Capolini that's it. That's the post. Lol. I knew you'd know. My consideration is that most of bigger lights get too hot before the timed step down can occur. But you have good points. I always manually lock out my lights to prevent any accidental issues.


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## Midnight.Sun (Oct 5, 2015)

Nice I'll trust you with the snow thing, host and lens , thanks Vampires.


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## more_vampires (Oct 5, 2015)

Midnight.Sun said:


> Ahem.. more-vampires is a brain boooster for sure, im trying to keep up, said trying, ahem..


Thanks man. Threads like this are what make CPF for me.


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## Midnight.Sun (Oct 5, 2015)

You provided great info, very rich thread because of you, definitely :thumbsup:

Just like to be sure, lens and host would be ok, even if dipped in melted snow = cold water , as there's no trapped 90% air there , ok right ? And is dipping time open, or just like dipping bursts ?

And thanks in advanced.


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## more_vampires (Oct 5, 2015)

If you start off in the water, probably fine. Super blister hot light into very cold water = not good, probably. Strength of materials says the host will fare better than the lens, but the lens has lower specific heat than aluminum, so that helps. Lower specific heat means that it contains less heat. Also, the lens doesn't absorb very much heat itself as it's designed to transmit as much light as possible. That alone helps protect the lens from thermal shock.

If you had a red filter on the light, then it resists transmission of light and would get hotter than an ultra-clear lens.

Thermal shock is at maximum when the temperature gradient is strongest and the change the quickest.

If rain fell upon your super hot light, I wouldn't worry about it.



> Just like to be sure, lens and host would be ok, even if dipped in melted snow = cold water , as there's no trapped 90% air there , ok right ? And is dipping time open, or just like dipping bursts ?



A quick dip, there's less time for energy transfer, thus less thermal shock. A full "quench," put it in there and leave it would stress the light body more.

However, it only takes a second to break something, like when you get a skillet super hot and quench it in cold water. A cast iron pan is more likely to crack than a thin aluminum because the amount of heat soaked in the thick iron is higher.


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## Midnight.Sun (Oct 5, 2015)

Got you, i knew you answered before on extremely hot light in 32F water = probably not, so i assumed that normal hot light with short bursts (dipping in water i mean) at the beginning, then gradually lengthening the time of dipping is in the safe zone for sure.

And the lenses are usually toughened = thick , by the way.


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## more_vampires (Oct 5, 2015)

I've not heard of a Vinh overdrive light cracking from thermal shock by turning it on and running it hard straight. Running an overdrive light in water from the first turn on has no real temperature gradient, and the change will be gradual thus probably ok.

It's when there's a sharp change, that is: throwing something that's painfully hot to touch into an ice bath. That ramps up the stresses involved.

It's like heating water in a cookpot on your stove. Not much happens until the boil, not much thermal stress. When you throw cold into a smoking hot skillet, that's when you get the sizzle. Thermal shock!


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## Midnight.Sun (Oct 5, 2015)

Nice one on the red filter, as i use that more often, and i add to yours, even if any filter shatters it is less cost than a shattered lense = water + LED = dead light

Won't dip fiters, especially red ones, no benefit also, I'll remember to take the filters off.


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## more_vampires (Oct 5, 2015)

It would take a pretty sharp temp gradient to shatter a red filter. It certainly can be done under the right conditions.

Fortunately if it's really that could outside, this is going to make the flashlight have a lower overall temperature. I suppose you could say that under normal conditions thermal shock is self-limiting in a few ways.

Another consideration is if the light has rather a lot of air space inside. It gets hot, air expands. It's going to want to "burp" past the seals to normalize pressure. Then, if it gets cold in an ice water bath the air will contract again. Under the right conditions, this could suck water inside.

Don't worry. You're not going to have to have massive airspace inside plus one heck of a hot light. Threat level? Minmal.


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## Midnight.Sun (Oct 5, 2015)

Ah, i have always thought about that, they do vent pass the rubber ? Don't they ? In normal use no water or snow threats.

After a while due to vacuum inside batery cabinet, or worse in the light head through the lens's rubber, they need to suck in some air again, and its an ongoing process, thus not not a thing called waterproof, unless maybe double o rings in the body, and thick D ring between lens and head wall, is needed for a full water proof and diving rated light.


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## more_vampires (Oct 5, 2015)

Under normal use? No. It would take some fairly large temperature differences.

Also, as the light gets hot by operation of ambient temperatures, air pressure inside the light must increase by Boyle's Law.

https://en.wikipedia.org/wiki/Boyle's_law


> *Boyle's law* (sometimes referred to as the *Boyle–Mariotte law*, or *Mariotte's law*[1]​) is an experimental gas law which describes how the pressure of a gas tends to decrease as the volume of a gas increases. A modern statement of Boyle's law is
> 
> The absolute pressure exerted by a given mass of an ideal gas is inversely proportional to the volume it occupies if the temperature and amount of gas remain unchanged within a closed system.[2]​[3]​​



​In most lights, the quantity of air is very small. It would take extreme changes in external pressure or temperature to do something.

As it heats, the pressure increases. If it reaches a threshold to "burp" past the seals, then upon cooling it could do it in reverse and suck in moisture.

Also, this could conceivably swell or pop off a switch boot or similar. There is no catastropic risk to this, aside from water intrusion and electrical shorting.

Now, if your batteries began venting, that effect is hot enough as it is. As the available volume is small, pressure shoots up in a hurry. This takes off the tailcap, light head, or both. In the big monster multibattery lion lights, this could rupture the body tube as well. It's not an explosion though. That's something specific. This would be "pressure rupture of a sealed vessel," much less of a hazard than your run of the mill shockwave detonation of certain nitrogen compounds. It would be bad, just not as bad as a real explosion.

It's in common parlance to say "blow up" and "explosion." Those aren't the right words.

Thermal shock is like the physics concept of "impulse." The duration of transfer of energy. The sharper (shorter) the impulse for a given amount of energy, the more damage it's going to do. So the flashlight changed 50 degrees, if it took an hour doing this no problem. If it did it in less than a second, that's a whole different level of stress.


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## Bigwilly (Oct 5, 2015)

more_vampires said:


> Under normal use? No. It would take some fairly large temperature differences.
> 
> Also, as the light gets hot by operation of ambient temperatures, air pressure inside the light must increase by Boyle's Law.
> 
> ...


Excellent explanation. So let me run this by you : 
If i can run my TK75vnQ on Turbo for 5 minutes at 85 degree ambient temperature. How long would it run at 50 degrees ambient?


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## Midnight.Sun (Oct 5, 2015)

more_vampires said:


> Under normal use? No. It would take some fairly large temperature differences.
> 
> Also, as the light gets hot by operation of ambient temperatures, air pressure inside the light must increase by Boyle's Law.
> 
> ...



Nice thanks, I thought this boyle's law sounded familiar it's been mentioned several times in the battery section.


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## more_vampires (Oct 5, 2015)

Bigwilly said:


> Excellent explanation. So let me run this by you :
> If i can run my TK75vnQ on Turbo for 5 minutes at 85 degree ambient temperature. How long would it run at 50 degrees ambient?


Lol, the math for that is going to be really nasty.

Let's say "it will run longer at 50 degrees ambient before stepdown in a thermal sensor stepdown light." 

Remember, a timer stepdown doesn't care what temperature it is.

By nasty math, I mean a whole lot of calculus and we'd have to throw in material composition, size mass and shape, surface texture, and probably a thousands other things as well. We'd need to know the rate of transfer between the light head and the body as well. Doing math like this involves something called "percentage error." That's the difference between the calculated value and the real-world measured value. If you're more than 25% off, your math is wrong.

Oh no! Not just calculus, but now we have to invoke statistics to prove how wrong we were! 

https://en.wikipedia.org/wiki/Error_analysis_(mathematics)#Scientific_data_verification
https://en.wikipedia.org/wiki/Error_bar


> *Error bars* are a graphical representation of the variability of data and are used on graphs to indicate the error, or uncertainty in a reported measurement. They give a general idea of how precise a measurement is, or conversely, how far from the reported value the true (error free) value might be.


Really, a calculation like that would be a senior project, a graduate term paper, if not a doctoral thesis.

If it's cold enough outside, theoretically a temp sensor light will not step down at all. What number that is? I'm not holding the data to do that and it'd take quite some time. Even then, I'd only be within a percentage of the correct number.

It's WAY easier to just try it. Far, far, far faster and it gives you the exact answer you were looking for.

I'm a fan of looking for ways to bypass math.


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## Bigwilly (Oct 5, 2015)

more_vampires said:


> Lol, the math for that is going to be really nasty.
> 
> Let's say "it will run longer at 50 degrees ambient before stepdown in a thermal sensor stepdown light."
> 
> ...


It won't be cold enough here for another few weeks and although I appreciate your in depth answers, I should of said I was looking for you to use the SWAG method. Scientific Wild *** Guess - LOL. Seriously, what would you guess, I have a time in my head and I want to see what yours is and then I'll let you know what my unscientific results are once it gets cold enough. 

also I posted something for you and anyone else to answer in my Lumen / Lux thread.

thanks


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## Midnight.Sun (Oct 5, 2015)

I will dip any light i have (except one heh) in the snow this winter and maybe water, as planned with much more confident.


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## more_vampires (Oct 6, 2015)

Bigwilly said:


> It won't be cold enough here for another few weeks and although I appreciate your in depth answers, I should of said I was looking for you to use the SWAG method. Scientific Wild *** Guess - LOL. Seriously, what would you guess, I have a time in my head and I want to see what yours is and then I'll let you know what my unscientific results are once it gets cold enough.
> 
> also I posted something for you and anyone else to answer in my Lumen / Lux thread.
> 
> thanks


SWAG? Heh. Okay, straight from the air with no numbers. I'd say you might get 10-15% more turbo runtime before thermal sensor stepdown.


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## Bigwilly (Oct 6, 2015)

more_vampires said:


> SWAG? Heh. Okay, straight from the air with no numbers. I'd say you might get 10-15% more turbo runtime before thermal sensor stepdown.



So that equals about 30 more seconds. Interesting, I was thinking 20-25% more. I appreciate your answer and I'm curious to see what happens once the temperature drops. Thanks as always for your insight.


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## more_vampires (Oct 6, 2015)

You could try it in a walk in refrigerator/freezer just for giggles.

Go to the convenience store and run it in the beer cooler or put it in the ice cream rack and close the clear lid. 

"What are you doing?"
"Testing a flashlight, what does it look like?"


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## Midnight.Sun (Oct 7, 2015)

more_vampires said:


> ...
> 
> Go to the convenience store and run it in the beer cooler or put it in the ice cream rack and close the clear lid.
> 
> ...


"..!!??"


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## Bigwilly (Oct 7, 2015)

more_vampires said:


> You could try it in a walk in refrigerator/freezer just for giggles.
> 
> Go to the convenience store and run it in the beer cooler or put it in the ice cream rack and close the clear lid.
> 
> ...



Lmao. That's freaking hilarious.


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## more_vampires (Oct 7, 2015)

Glad I pulled a funny, guys! Cheered me up, too.


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## WarRaven (Oct 7, 2015)

One small part of me looks forward to minus 30c temps,...
New lights!
Can't wait to honestly try ATR in the real outdoors here.


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## Bigwilly (Oct 7, 2015)

WarRaven said:


> One small part of me looks forward to minus 30c temps,...
> New lights!
> Can't wait to honestly try ATR in the real outdoors here.



-30c must play hell on your batteries. That's polar bear and penguin weather. Lol. Seriously, do you see a large drop in battery performance in such cold temperatures?


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## WarRaven (Oct 7, 2015)

Bigwilly said:


> -30c must play hell on your batteries. That's polar bear and penguin weather. Lol. Seriously, do you see a large drop in battery performance in such cold temperatures?


Honestly, last three or four winters I've been using NiMH lights.
I had a couple old Surefire, ran them on AW RCR123, got maybe ten to twenty minutes run time, not much better on primaries. 
Mind you, that was years ago.

I've no cold weather experience with 18650 and their lights yet, but old man winter is coming and darn straight I'll be posting my findings.
Though, to answer your question, yes I have saw lights just shut off in cold in my usage. 
Until beginning of this year I used to drive a tow truck for a big company doing emergency roadside recoveries.
Saw all sorts of flashlight casualties, lost one too, so I carried three minimum on me. 
Yes, I'm used to cold weather.


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## Bigwilly (Oct 7, 2015)

WarRaven said:


> Honestly, last three or four winters I've been using NiMH lights.
> I had a couple old Surefire, ran them on AW RCR123, got maybe ten to twenty minutes run time, not much better on primaries.
> Mind you, that was years ago.
> 
> ...



Is NiHM less susceptible to the cold? Have you thought about wrapping a light in some sort of thermal insulation so once you go out side they retain as much heat as possible?


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## WarRaven (Oct 7, 2015)

Thanks for the thoughts, I no longer drive wrecker but still spend most of day outdoors of house anyhow.

The NiMH lights were charged daily an used hard, they got dimmer some nights then I wanted but kept working with me. 
At the time I only had NiMH lights I trusted so I never thought of dragging Surefires out an trying that, run times were not acceptable even when used in summer but was high power guilt free then.

This winter I'm going to play around with wrapping materials, depending on light, I carry inside jacket but once it's out, its out in open with me and I'll get an idea of run times an outputs compared to my summer run times, I'm expecting about half but hoping lights internal heat will help offset cold some.
Then ATR should be a win-win, self heating an cooling ☺


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## jmwking (Oct 7, 2015)

Bigwilly said:


> Is NiHM less susceptible to the cold? Have you thought about wrapping a light in some sort of thermal insulation so once you go out side they retain as much heat as possible?



Gloves?



-jk


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## SemiMan (Oct 9, 2015)

Bigwilly said:


> As light outputs keep going up and size keeps going down at some point better thermal management is going to be needed. Some of the modded lights only get a few minutes of runtime on their highest setting. I've searched but haven't found much of what is being done to help with thermal management. At the cutting edge, I would think active cooling would be on the horizon. I asked one well known modder and he told me active cooling and waterproofing don't mix yet. Are any manufacturers working on this? Any other ways for managing heat? I thought I saw a post where a member had a light that had a modded computer liquid cooling system in the light but it didn't go into much detail. Are there any other lights out there like this? I just see a light small enough for a belt holster that puts out 14k lumens but only for about 3 minutes and can't help but think if some kind of thermal management would increase it to say 20 minutes would make the light so much more usable.



Actually, in many cases, as the light output has been going up and up and up, the problem has not been getting a whole lot worse, at least at the LED level.

When I was doing:
- 1000 lumens at 50 lumens/watt, I was dumping 17 watts of heat almost. 
- Then at 100 lumens/watt, 7 watts of heat. 
- Now at 200 lumens/watt, I am dumping < 2 watts. 

(All figures rough ... and all LED lumens without optical losses).

One of the "problems" we have, is often we are pushing for maximum through, so even though we have a LED capable of 200 lumens/watt, we are running it at 100 lumens/watt for best throw.

So, I can now do 10000 lumens with the same LED heat load as 1000 lumens at 50 lumens/watt. When we start topping out with current LED tech in the 250 - 270 range, I could be into an LED heat load of 5 watts .... quite manageable.

Let's do a practical example of 10000 lumens at 150 LPW = 66 watts electrical, and about 33 watts of heat load at the LED. 150 LPW ----- I am going to use LED and system level efficiency interchangeably for ease of calculations.

The LED of course is not the only source of heat. I also have the electronics. Let's say I am doing 10000 lumens at a "practical" 150 lpw, or about 66watts. Now we are running into aspects of practicality and cost (and designer knowledge). If I start with a "reasonable" 12V battery, then hitting say 93% efficiency is pretty easy for this light, which means 0.07 * 66 = 4.7watts .... which is a reasonable amount to get rid of. Now let's say I take cost of the electronics out of the equation, assume I have the space for the right components, and get that conversion efficiency up to 97.5%. Now I am only getting rid of 1.65W ... again, quite manageable. I can use thermal compound to get the electronics heat out to the case for maximum cooling.

I have two other sources of heat. One, optical losses, lets say 10% to start or about 1000 lumens @ 300 lumens/watt = 3 watts. I may be able to use special coatings to get that down to lower, but 3 is a good starting number.

The other source of heat is the battery. Let's say I have 100mohm cells, 3 in series, 300mohm. 12V, 66W = 5 amps roughly, or 1.5W. I am going to double up my batteries and get that down to 0.75W. We also need to consider as the batteries age, that could creep up to 2W.

So 10000 lumens, 150 LPW ----- I am going to use LED and system level interchangeably for ease of calculations

66 watts
- 33 is heat of the LED
- 3 watts optical losses (Could be 2-5)
- 2 watts electronics (they are good electronics) (But could be 1.5-10)
- 2 watts batteries (But could be 1-5 or more)

These are all ranges and your mileage may vary, but it does give you an idea of what is possible.

Now when we are at 250 lumens watt, we now have 40 watts from the batteries, and the figures start to look like:

- 7-8 watts at the LED
- 2-5 at the optics (does not change)
- 1.2 - 7 at the electronics (scales linearly)
- 0.6 - 3 at the battery (scales linearly -- but these are likely to get better too).


Advanced in LED tech will significantly reduce the heat issue.

The other advancement in LED technology is high temperature operation. Hence you could have an "isolated" head that ran hot and dissipated a lot of heat, while the batteries and electronics were allowed to stay cool.


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## Bigwilly (Oct 9, 2015)

I still think some form of active cooling is what is needed as the power of our flashlights goes up.


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## MidnightDistortions (Oct 9, 2015)

Kestrel said:


> I found that the best way to avoid the thermal limiter on the OR/Torchlab V.4 XPG Triple was to take the flashlight on a walk in below-freezing temperatures. Could be a challenging solution in some regions though.



Would be great to have as a hand warmer


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## Bigwilly (Oct 9, 2015)

MidnightDistortions said:


> Would be great to have as a hand warmer



Then you have a reason to buy 2 of them. Lol.


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## Gunner12 (Oct 11, 2015)

All the heatsinking isn't going to help if there are voids in the LED or in the LED solder connections. Came a cross a study on LED stability today talking about voids and seem relevant here.
Here's a study by Cree:
http://www.cree.com/~/media/Files/C...pplication Notes/Solder Joint Reliability.pdf

and Osram:
http://www.osram-os.com/Graphics/XPic0/00091433_0.pdf/Processing of SMD LEDs.pdf

(The studies, goes into a lot more depth then I wanted to read, but the pictures show the issue well)

If we could get more efficient LEDs... then we get less heat!
What if you carried the light in a clear case/bottle, and filled that case with water? The bottom of the case would have to be flat as not to distort the beam. If the case starts to get hot, just change the water.


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## Bigwilly (Oct 11, 2015)

Gunner12 said:


> All the heatsinking isn't going to help if there are voids in the LED or in the LED solder connections. Came a cross a study on LED stability today talking about voids and seem relevant here.
> Here's a study by Cree:
> http://www.cree.com/~/media/Files/C...pplication Notes/Solder Joint Reliability.pdf
> 
> ...



Good thought but water weighs over 8 pounds per gallon so I think the case would be too heavy.


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## more_vampires (Oct 12, 2015)

Gunner12 said:


> All the heatsinking isn't going to help if there are voids in the LED or in the LED solder connections. Came a cross a study on LED stability today talking about voids and seem relevant here.
> Here's a study by Cree:
> http://www.cree.com/~/media/Files/C...pplication Notes/Solder Joint Reliability.pdf
> 
> ...


Reading now, thanks for the links. I love reading stuff like this!

Edit: MAN is that some science!  Awesome. Looks like we're looking at 600 to 3000 cycles before a good chance of failure when a super high-drain light is started from -40 degrees. Cold solder joints (>50% void) result in failure.

From this, I was reinforced one more time that lead-free is garbage for electronics.


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## more_vampires (Oct 12, 2015)

Bigwilly said:


> Good thought but water weighs over 8 pounds per gallon so I think the case would be too heavy.



Yeah, with that much weight just carry a travel cooler of beer. Occasionally throw the light into it and maybe get a brew while you're in there.


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## Bigwilly (Oct 12, 2015)

more_vampires said:


> Yeah, with that much weight just carry a travel cooler of beer. Occasionally throw the light into it and maybe get a brew while you're in there.



Good call on the alcohol. Lol.


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## Rick NJ (Oct 12, 2015)

SemiMan said:


> ...Let's do a practical example of 10000 lumens at 150 LPW = 66 watts electrical, and about 33 watts of heat load at the LED. 150 LPW ----- I am going to use LED and system level efficiency interchangeably for ease of calculations.
> 
> The LED of course is not the only source of heat. I also have the electronics. Let's say I am doing 10000 lumens at a "practical" 150 lpw, or about 66watts...
> ...



"The LED of course is not the only source of heat" is an important point. High current in particular will have an out-of-proportion negative impact. Every wire and every connection, each is a resister. It may be very low resistant but a resister non-the-less.

Power = Voltage * Current; Since Voltage= Current * Resistance, you have
Power = Current2​ * Resistance
In other words, for twice the Power at the same voltage, the Current doesn't double but go up by square.

For a mere 0.1ohm, 3A going through it will generate 0.9Watt. Even typical DMM probe wire will be around 0.05ohm, and a screw-in contact may have 0.01ohm. When in closed environment with high current, it can heat up pretty well.

I had a 16AWG wire with spring loaded 10A fuse connected to a socket. The *socket* was rated for 20A. So, I fully expected the thing to be able to carry 6A. But I was getting something strange. Carefully checking, by the time I pushed that to 4A to 5A, The fuse contact spring was heating up so much the spring melted enough of the plastic to unseat the fuse. Inside that holder, the plastic melted enough to have a molded impression of the spring.

Back to flashlights. That small contact resistance will affect your performance. I just got into the LED flashlight thing by starting with a pair of budget lights. The pair was same as in same model and probably same manufacturer. *One flashlight-body was constantly drawing less current than the other* even after I swap the LED/Driver pill. It turns out to be dirty screw threads (or bad lubricant with poor electrical conductivity). After cleaning it with soup, the two flashlight has much closer current draw. It affected the top current by about 10% even at the low range of 800mA-900mA. When there is enough resistance to create a 10% delta with amperage, it would certainly be enough resistance to create more heat.

That is higher voltage (serial 2x18650 vs 1x18650) is more efficient at least electrically-speaking.

Rick


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## more_vampires (Oct 12, 2015)

You're sharp, Rick.

I hear what you're saying on resistance causing problems. A common mod here on CPF is called a "spring bypass" where we bypass the poor conduction natures of most springs with a simple short copper wire shunt from head to tail of the spring.

This, and clean threads. I agree 100%.


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## Rick NJ (Oct 12, 2015)

more_vampires said:


> You're sharp, Rick.
> 
> I hear what you're saying on resistance causing problems. A common mod here on CPF is called a "spring bypass" where we bypass the poor conduction natures of most springs with a simple short copper wire shunt from head to tail of the spring.
> 
> This, and clean threads. I agree 100%.



Ah ha, interesting. Being a newbie in flashlights, I did not know about the "spring bypass". Learn something new today so today is a good day. 

Thanks!


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## more_vampires (Oct 12, 2015)

NP, various CPF testers report a gain of up to 100 lumens by spring bypass, depending. Not all lights can benefit from this, depends heavily on well... everything. Some lights will show no visible gain. In some lights, 100 lumens is not detectable without equipment.

I've got a couple p60 copper triple modules from CPFer Vinh Nguyen with that. Those modules rock.


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