For best cooling should I hug/squeze flashlight or not for best heat heat dissipation

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Ekstasis
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For best cooling should I hug/squeze flashlight or not for best heat heat dissipation

For best cooling should I hug/squeze flashlight or not for best heat heat dissipation
I have always wondered this.. I tend to squeze it when it gets warm… in the winter it can actually be nice… if you don’t have gloves..but from scentific point of you what will dissipate the heat best the hand or the air ?

crn3371
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Air circulation is your friend.

Notmyrealname
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Might depend somewhat on the air temperature. It can be over 30° at night here. Also, I wonder if humidity has any effect on heat dissipation.

I feel sorry for people who don't have a hobby or interest to escape to.

Firelight2
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My recollection is that conduction into your bare hand is supposed to be better than convection into surrounding air. This is why temperature-regulated lights tend to run at higher output longer when held in the hand versus tail-standing out in the open.

That said, there are many factors such as:

  • the design of your light
  • air temperature
  • wind
  • your hand’s temperature

CvR_XX
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Notmyrealname wrote:
Might depend somewhat on the air temperature. It can be over 30° at night here. Also, I wonder if humidity has any effect on heat dissipation.

Humidity would have an effect if there is moisture on the surface of the light. If a person is sweating it’s to cool down the body but it’s not the actual sweat that cools you down. The thing that is cooling you down is the evaporation of the sweat. For the phase change to occur a significant of energy is required. This energy will come from your skin hench cooling it down.

When there is a relatively high humidity there is less “space” for water in the air. This reduces the ability for sweat to evaporate and cool you down. This is why humid weather feels so warm.

So if there is moisture on the light humidity would matter.

zoulas
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Using your own flesh as a heat sink is not a good idea. You will burn yourself long before you cool down the light.

Unheard
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I think it helps dissipating heat. If the light is already hot, it is surely not a good idea.

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TIFisher
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zltwo
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Your hands have high blood flow, and will indeed cool down a hot light.

If the light has Narsil or Anduril, you can adjust how hot the internals get, to prevent skin burns.

texas shooter
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Your hand is a good heat sink and has a build in thermal sensor array. This thermal controller has three different independent channels. Touch, this is really getting hot. Audio, sizzling noise. Olfactory, who’s cooking chicken?

Notmyrealname
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If I need to run turbo or high longer then my setting will allow I’ll lower output or turn off momentarily, let the light air cool for 10 seconds or so and then squeeze the head of the light with my hand and sometimes switch hands back and forth. It cools the light much faster. Of course don’t do this if the light is still too uncomfortably hot to touch unless you wet your hand first with BBQ sauce.

I’ve been thinking about testing a lights heat dissipation using our ambient temperature here vs putting the light in the freezer. (about 30°C vs -30° or the difference between the tropics and a northern winter night). Of course the faster a light gets hot (FWAA?) the less effect air temperature will have so unsure of how useful it would be.

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jon_slider
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Yes, handheld cools better than freestanding in air. Even though my hand is hotter than the air.

zltwo wrote:
Your hands have high blood flow, and will indeed cool down a hot light.

If the light has Narsil or Anduril, you can adjust how hot the internals get, to prevent skin burns.

I agree Thumbs Up

I did a test with my Copper FWAA w SST-20 4000k

I use a Calibrated Light Meter to detect thermal step down

I set the ceiling of my FWAA to 400 lumens (90/150), turned it on and put it on the light meter..

the thermal protection I have set to 40C triggered after a few seconds and the output started to drop below 320 lumens.

I then picked up the light, held it in my fist for a few seconds, then put it back on the light meter and got a reading of 390 Lumens.

iow the output went up when handheld

wle
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i would not do that

the only time heat is a problem, is also above safe temps for human skin

ie either the light will not need the cooling, or you will get burned

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NeutralFan
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It seems dissipating heat through your hands will be faster than air. I’ve done this numerous times in order to cool down a flashlight that has gotten very hot when calibrating the high end temperature. If it gets too hot to hold, then move the flashlight between hands until it cools down.

But if you have a flashlight with large fins around the head, then perhaps air will help dissipate the heat faster. Probably depends on the flashlight.

I’d rather use my flashlight around the house than turn on the lights.

jon_slider
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wle wrote:
the only
Im not sure we have the same goal in mind

the goal of my test was to prevent thermal stepdown, using a 40C thermal limit

I wanted to find the sustainable output both freestanding and handheld

The safe and sustainable freestanding Lumens level of my FWAA is 200 lumens, with thermal ceiling at 40C.
Thats my Simple mode ceiling.

for my Advanced ceiling, I set 400 lumens, after a series of test showed that the thermal regulation would not trigger a lumen drop, when handheld.

400 lumens does trigger a lumen drop when freestanding, also with thermal limit at 40C

from this I clearly understand that my hand lets me have twice as many lumens, as the air, without triggering thermal stepdown set to 40C

make sense?

wle
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jon_slider wrote:
wle wrote:
the only
Im not sure we have the same goal in mind

the goal of my test was to prevent thermal stepdown, using a 40C thermal limit

I wanted to find the sustainable output both freestanding and handheld

The safe and sustainable freestanding Lumens level of my FWAA is 200 lumens, with thermal ceiling at 40C.
Thats my Simple mode ceiling.

for my Advanced ceiling, I set 400 lumens, after a series of test showed that the thermal regulation would not trigger a lumen drop, when handheld.

400 lumens does trigger a lumen drop when freestanding, also with thermal limit at 40C

from this I clearly understand that my hand lets me have twice as many lumens, as the air, without triggering thermal stepdown set to 40C

make sense?

==not really
what about “moving to alaska for more lumens”?

or just ‘get a light that is designed for your actual needs”?

"You never have the wind with you - it's either against you, or you're having a good day."
    Daniel Behrman, "The Man Who Loved Bicycles".
It never gets easy, you just go faster.   
-Greg Lemond.
       ,ø¤º°`°º¤ø¸,ø¤º°`°º¤ø¸,ø¤º°`°º¤ø¸