HARMFUL,HARMELSS OR A LITTLE OF BOTH?

This is pertaining to LED flashlights only! They are the only kind I have and the ones that I used for this experiment, if you will.

This may seem like mostly common sense, But I wanted to be sure. OK,,,,,I have numerous modded and high powered lights. They all generate a lot of heat. Rule of thumb is when they get too hot to hold dial them down. I actually turn them down before that. When my thumb which is near the neck/switch/control ring, begins to feel too much heat I dial it down a notch or Two!

Here is the situation. It is winter time and snow is on the ground.The light is starting to get hot. I got this brainiac Idea to put the head of the light in the snow for ~5 seconds. The light was cooled down immediately as one might expect! Hey,,,,,now I can do another 15 minutes or so of a run on turbo! This light puts out~ 6800 lumens. It is One of only Two that will still get hot when temps. are below 20F/6.6C.

I only did this once and I will point out that even when this light gets too hot, it is thermally regulated to protect it. My thinking is no harm no foul!

How about for a light that is NOT regulated like this? Or even this light if I did repeated runs of turbo after cooling in snow?!

Even though the outside of the flashlight is cooled,,,what about the driver and other internal components?

These are my thoughts:

I THINK THE "ACT ITSELF" [COOLING IN SNOW] IS HARMLESS TO THE LIGHT. HOWEVER, WOULDN'T REPEATED RUNS OF CONTINUALLY BUMPING BACK UP TO TURBO BE POTENTIALLY HARMFUL TO THE DRIVER AND OTHER INTERNAL COMPONENTS?



What are your thoughts Ladies and gentleman? Could I have possibly resolved the enemy called "Heat",,,,,,,,,,,,,,just for the winter?!

Thinking about thermal path, this wouldn't help much in a plastic host.
Thinking about rapid thermal cycling, yeah maybe that's not so good.

Considering this: Like overclocking a PC?

Back in the day, there were some crazy college students that modded their kitchen freezer with motherboard standoffs, PCI rack, etc. They then went to great lengths to find/mod a motherboard to be overclocked to absolutely unheard of levels. Since they were college students, they did this with an "old" mobo/cpu. They received added style points for modding heat sinks to be little tables for bottles of freezer-temperature liquor.

Even in the freezer, the system would go unstable in only a few minutes. Think they managed to get the system to load Half-life 1 before system hang.

In their zeal, they hadn't considered a few things and error analysis showed that heat buildup on the underside of the mobo was the culprit.

They didn't have the zeal to try a liquid-cooled full-immersion build. That's an expensive place to play.

Summary: So, Cap... Shall we invent the active water-cooled flashlight? Worked for OCing PC, why not ODing LED? :thinking:

People have talked about it before! :naughty:

http://www.candlepowerforums.com/vb...tive-cooling-in-lights&highlight=water+cooled
http://www.candlepowerforums.com/vb...300-watt-LED-prototype&highlight=water+cooled

NiteCore advises against cooling TM26 light by immersion in water because internal contraction of air from temperature drop could suck moisture into the flashlight- something like that.

That must be some pretty souped-up torches being left on for awhile, you've got there.

KITROBASKIN said:

NiteCore advises against cooling TM26 light by immersion in water because internal contraction of air from temperature drop could suck moisture into the flashlight- something like that.

That must be some pretty souped-up torches being left on for awhile, you've got there.

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I have several of them but only my new TN36[~6800 Lumens] and my X2vn single cell 18650 ~1500 OTF still get hot in below freezing weather.

Same concept of cooling them down but this is a bit different. I am not dispersing them in water. I am just lying them in the snow for about 5 seconds.

You still stand the chance of breaking a lens being rapidly cooled, even though your not trying to cool the lens. Also, there is thermal transfer of heat to the batteries as well as the heat that a high amp draw on the cells create.

I look at it this way. The manufacturer designed the light using a thermal management plan. Call it timed or actively monitoring the temperature, it's all the same. Since you are using highly modified lights that create even more heat than what was designed for, even additional heat sinking probably only gets you back to where the OEM designed the light for if used at full power.

KITROBASKIN said:

NiteCore advises against cooling TM26 light by immersion in water because internal contraction of air from temperature drop could suck moisture into the flashlight- something like that.

That must be some pretty souped-up torches being left on for awhile, you've got there.

Click to expand...

...But Lux-RC was working on it! Fan cooling, not coffee-pot style valves.

more_vampires said:

...But Lux-RC was working on it! Fan cooling, not coffee-pot style valves.

Click to expand...

I have a tiny biscuit fan mounted on a heatsink surrounding the motor on my Mini Revo radio control car. It does a bang up job with keeping things from getting too hot. I keep waiting to see someone mounting something like that on an Oveready Wasp head, but i don't think that will help our friend here.

Whenever you overdrive something you are shortening its life to have the higher performance, so if you use this cooling method to run more high output cycles, you will 'use up' the life of the device all the faster. From my perspective, any overdriven device is 'for the fun of it', so should be considered almost disposable. If you want a long term reliable light, don't overdrive it.

I might be more concerned about the thermal shock on the lens more than anything else, plus, cooling the housing will not immediately cool the driver circuit to the same degree. So carrying out this BLAST - rapid cooling - BLAST - rapid cooling.... is taking the over drive to yet another level.

When I carry out my runtime tests, I am running lights on their maximum output, and during this time I am using forced air cooling with a small powerful fan directed at the head. This cooling approach does not introduce any shock, instead increasing the heat transfer. The driver circuit will be running at the maximum level for a considerable time, but at normal levels rather than over driven. Perhaps if you used the snow to cool the light as you are using it (grab a a handful and hold it onto the light) there would be less chance of damage as you would be stopping the light from getting too hot in the first place.

I would suggest discussing this with Vinh, as his recommendations for using overdriven lights might also be factoring the load on the cells as well as the driver and LED.

In summary, I think you might cause the lens to break and by increasing the number of maximum output cycles while perhaps not fully allowing the driver and cells to cool properly you will be reducing the expected lifespan of the light faster than normal. If you are having fun with your overdriven toy, then have fun, but don't cry when it breaks.

Thanks everyone for the insight.

The one thing I did not think of was possibly cracking the lens like a few of you mentioned.That would be my main concern for this[TN36] specific light.

This is definitely something that I would not continue to do because of the internal components being over worked. That would be my main reason and concern. Not so much for this light but others that don't have its feature of ITC-INTELLIGENT TEMPERATURE CONTROL.

I just thought of something! IF, AND I AM NOT, I were to continue this "snow cooling",,,I wonder if it would "FOOL" THE ITC? I wonder if the ITC is specifically designated for internal temp., external temp or OVERALL TEMP. of the light?

The TN36 was my volunteer! I tried it once the other night and once last night. If I chose to continue to do this which I am NOT, my concern would be what others mentioned and I did not think of,,,,,,,,,,,that is the lens possibly breaking. Again,As far as the heat build up for this light,,,that would not concern me as much because it is thermally regulated. So even if it is too hot to hold[as SB pointed out] I think the thermal regulation is still working to protect this light.

I would not even consider doing to this with my high powered Vihn lights. That is about 70% of my collection. I want them to last! Once they get hot I dial them down. Several of them can go 15, 20 minutes in the summer w/ out getting too hot,,,,,,,,,,,,One of which is my TK75vn KT which is my favorite. The SR52vn NEVER gets hot,,,,it can be 85F right after sunset and you can use it for 40 minutes on max!

Another one is my OSTS TN31mb,,,,,,,,,,,never gets hot,,~800 lumens and 470Kcd.

I hadn't considered external ice cooling and confusion of the thermal monitoring. Great point. That's possibly a real issue right there.

If the light has a good thermal path, the internal temperatures should track with the external temperatures.

Whether or not you can really fool the temperature circuit depends on where the sensor is located. Ideally it should be located on or near the components that are in the most danger of being overheated, which on some lights it is the driver and others is the LED(s). If your light has the sensor in the "right spot", then you shouldn't be able to fool it by rapidly cooling the exterior of the light.

What I would be most concerned with, as a few others have pointed out, is moisture ingress (or condensation of moisture already inside the light) and cracking the lens.

In short if you did in once, it wouldn't be good for the light. More than that it would be HARMFUL.

Now if your using it in the appropriate manner ( say a weapon light in freezing rain ) there should be a reasonable expectation that the light is up to the task.

Stick with snow angles, there're free and don't require repairs for abuse or using them for purposes that are considered outside of normal operation.

I'm going to disagree with pretty much everyone here I think, but I bet you'd be all set except in the circumstance that your thermal path is compromised, but in that case the driver or led won't last too long anyway.

I also highly doubt you'd crack a lens, it's not a six foot wide windshield where the differential of temperature from one spot to another would cause stress. By the time the edge of the lens is cool the center won't be all that far behind, and the change in dimension would be tiny over such a short distance.

I'd be mute worried about the batteries, but only because rapid temperature cycling them just sounds bad.

But, who knows. The only light I gave that makes that much heat is direct drive, and can run indefinitely as far as I can tell, so no data point to be gained.

This MAY change peoples assessment of my experiment!! http://www.sherv.net/cm/emoticons/confused/confused-face-smiley-emoticon.giff

I did not specify that the ONLY part of the light that was in the snow was the head. The lens and body never touched the snow. I simply rotated the head in the snow for ~ 5 or 6 seconds from a horizontal position! That may have some bearing on peoples concerns about the lens and maybe even the batteries?

http://www.sherv.net/cm/emoticons/shocked/wow-smiley-emoticon.gif

oh,yaa,,,,,WELCOME RMM [Richard!] http://www.sherv.net/cm/emoticons/smile/happy-wink-smiley-emoticon.gif

See Rule #3 Do not Hot Link images. Please host on an image site, Imageshack or similar and repost – Thanks Norm

I can't imagine sticking the head in some snow for a few seconds (or even a few minutes) would cause the light to die. I agree with onetrickpony, these lights are designed to get heat from inside to outside, which also means they can get "cool" from the outside to the inside. Cooling off a hot light is good for it.

It's not like you're dipping it in liquid nitrogen! Snow is cold, but it's not so cold that it can damage electronics.

Neither do I think it's a risk to the batteries. A dip in the snow isn't going to instantly cool down your light. It will take some time for that cold to reach the inside electronics and batteries, and besides I really doubt they'll get anywhere close to the temperature of the snow if you're running the light on max.

My only concern would be the glass lens. So, I'd avoid sticking the lens right in the snow. Lay it on its side or something like that.

WITL has come up with a capital suggestion!

The liquid cooled flashlight that Cap and I are inventing takes liquid nitrogen. PERFECT!

WalkIntoTheLight said:

My only concern would be the glass lens. So, I'd avoid sticking the lens right in the snow. Lay it on its side or something like that.
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That is exactly what I did young man! I just did not use the word "side" when I said I rotated it in the snow! My description was not 100% clear!
http://www.sherv.net/cm/emoticons/embarrassed/embarrassed.gif

See Rule #3 Do not Hot Link images. Please host on an image site, Imageshack or similar and repost – Thanks Norm

Capolini said:

WalkIntoTheLight said:

My only concern would be the glass lens. So, I'd avoid sticking the lens right in the snow. Lay it on its side or something like that.
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That is exactly what I did young man! I just did not use the word "side" when I said I rotated it in the snow! My description was not 100% clear!

Click to expand...

This is on par with snow angles then.

I think everyone thought you were maxing out the light temp and sticking it in the snow. :shrug:

Rolling a head in the snow ? Why?