P1D CE + Thermography

[wojtek_pl]

I don't have a P1, all i can compare to is an L1T,L2T,L0D, or an Inova X03/X02. which ones do you guys want to see?

Well... All of them of course !

 

[heliyardsale]

I have a FLIR Thermacam P65. It uses a Focal Plane array uncooled microbolometer at 320*240. It can accurately measure from -40C to+1500C (at different ranges). www.flir.com should be able to tell you all you need.

3.9 watts! wow that's a lot of power! :wow:

61C wasn't the hottest, i stopped while it was still rising, albeit slowly. (i want an old and healthy P1D CE)

Andron Frolov
theLEDoutlet.com

Great now you did it, I want a Thermacam. Damn! What is the lowest price and the best place to buy one? Thanks,
Heli

 

[LEDoutlet]

heliyardsale,

uhh, well thermacam pricing goes from around US $8000-60,000+, +accesories. If you are still interested i'll see what i can do.

 

[LEDoutlet]

New shootout is up at the top if you're interested...

 

[LEDoutlet]

Qben,

I am not sure of the max temp for LiON vs. Alkaline vs. NIMH batteries but if the battery can survive the heat i can tell you what temp the P1D CE gets to on medium (still plenty bright) if you'd like

 

[Qben]

This is a particularly interesting thread to me because I am a Firefighter and have been lurking here in search of a small light to mount on my helmet. It would probably never run for more than 30 minutes at a time and rarely in any signifigant heat. Would it be foolish to try and use the light in moderate temperatures...say 150 degrees F? I lean towards the P1D-CE because of it's size and light output, but maybe LEDs are simply not suitable for my needs.

 

[eebowler]

Very COOL! (HOT!) I'm confused now though however, are all lights run at the highest level?

 

[LEDoutlet]

yes, all lights are run at the highest level. also, after i was done with the test i grabbed the P1DCE like i would when using it and within 45 sec the temp dropped 15C.

 

[SpeedEvil]

Greenlight,
Emissivity is too large a topic to completely explain here but suffice it to say, Matte Black (or any matte color really) will radiate heat much better than any chromed color if they are the same material. IE) Matte Black, Brown, Blue etc. paint will radiate better than any shiny black, brown, blue etc. A lot depends on the material and if you look at my pictures closely, why do you think you can see Fenix P1D? that part isn't any cooler, it just has a lower emissivity.

This isn't really right, the colour at visible wavelengths is not important, it's the colour at infrared. (at least till you get up to several hundred C)
See http://www.etiltd.co.uk/emissivity_table.htm .

Emissivity isn't wholly important at these temperatures for flashlights - most of the heat is lost by convection.

Stephan-Boltzmans constant is around 6*10^-8.

60C is 330K or so.

Emissivity in watts per square meter is therefore 330^4 * 6*10^-8 *0.85 (the emissivity), or 600W/m^2.

A P1D is what - 20mm*50mm or so, or 60mm*50mm rolled out flat (this will void your warranty), or 3000mm^2. Or .003 m^2.

This makes the heat emitted 1.8W or so.
In an environment at 25C, it'll absorb around a watt, so the total is .8W.

Convection and conduction are much more important.

 

[LightBright]

~ 20mm x 72mm. I calc'd 5,151 sq mm

 

[SpeedEvil]

This is a particularly interesting thread to me because I am a Firefighter and have been lurking here in search of a small light to mount on my helmet. It would probably never run for more than 30 minutes at a time and rarely in any signifigant heat. Would it be foolish to try and use the light in moderate temperatures...say 150 degrees F? I lean towards the P1D-CE because of it's size and light output, but maybe LEDs are simply not suitable for my needs.

It will probably work fine.
At 150F, I wouldn't rely on it to work for more than a minute or so.
It might - but...
If it was me, I suspect I'd be looking at a 6 cell lithium (18650?) pack, and a 20W or so halogen bulb with sealed reflector.
Pack worn inside clothes, out to bulb on helmet.
Done right, this will produce light while the helmet lasts.
I assume there are lights already like this.

 

[Mike abcd]

Thanks for posting this information. I was already trying to be careful not to run the P1D CE on high more than a few minutes unless I was holding it. This makes me more so.

If you ever check the P1D CE on medium, I'd be very interested in the results. I'm far more likely to run it for long periods on medium in candle mode for room lighting (not holding it) than on high due to the significant increase in battery life.

Mike

 

[IsaacHayes]

Perhaps run the test with it on medium to see how much a differnce in heat there is? I bet low is cool enough to not even warrent the test.

 

[eebowler]

Ok I'm sorry, a bit tipsy now... What's the output of these lights at max power? I'm thinking that it would be a better comparison (the comparison would be more meaningful) if we knew the relative outputs of these lights. If the P1D CE is outputting more power than the others, duh, it should get hotter given all other conditions equal.

Sorry, I'm not familar with any of these lights. Can someone help?

Thanks.

 

[LEDoutlet]

Speedevil,

I know that the color doesn't matter, i was trying to explain for non-thermographer types that's why i said "Or any color really". sorry if i wasn't clear. also, I agree that radiation doesn't play a huge part in heat loss at this temp. the point of this exercise was to see how hot the lights got in normal use. I happen to have an IR camera, so i used that (with electrical tape at .95 emissivity).

Mike abcd,

I'll run the tests on medium, but it will probably be in a few days. am very busy right now.

thanks all,

Andron Frolov

 

[Xygen]

Ok I'm sorry, a bit tipsy now... What's the output of these lights at max power? I'm thinking that it would be a better comparison (the comparison would be more meaningful) if we knew the relative outputs of these lights. If the P1D CE is outputting more power than the others, duh, it should get hotter given all other conditions equal.
Sorry, I'm not familar with any of these lights. Can someone help?
Thanks.

The P1DCE is about 3 times brighter then the L2T.
I did some shoe box integrated sphere measurements:
L2T: 79 Lux
P1DCE: 230 Lux on High
L1P: 40 Lux (don't have the L1T)
These Cree's are really impressive. For comparison: My SF L4 reaches 240 Lux

 

[waion]

Those picutures are interesting and beautiful.

 

[eebowler]

Xygen, thanks but, I'm not talking about brightness, I'm refering to power to the LED as in Current x Voltage

 

[NewBie]

Keep in mind, the heat is generated by the battery, the converter, and the LED.

Here is a thermal image of the A19 XR-E:

If I recall correctly 1/4th more of the heat is radiated in a black bodied "flashlight" vs. my testing of a shiny, but not mirror polished "flashlight", once it starts warming up.

I did some testing about a month ago, to see the differences between two pieces of aluminum, one black and one shinny:
http://candlepowerforums.com/vb/showthread.php?p=1774679#post1774679


I do believe there is something very wrong with your numbers, as testing and calculations show quite different results, and show that whether the surface is shiny or black, makes a big difference on the temperatures.


There is a handy online calculator where you can go and plug in your numbers:
http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/stefan.html

 

[Mike abcd]

...
Mike abcd,

I'll run the tests on medium, but it will probably be in a few days. am very busy right now.

thanks all,

Andron Frolov

I asked for the test on medium because I thought I was seeing much lower temps on high than you and was concerned about the heat sinking in my P1D CE. Hence my reluctance to run it long term even at medium.

i finally realized that I was checking it on medium with an RCR123. Although I couldn't visually see the difference from high with the cell 50-75% charged, my light meter could when I checked. The actual output was higher than medium on a CR123 but still lower than it would be on high.

On high, I saw about 120 deg F on the head with a cheap IR thermometer after 10 minutes so my heat sinking is probably ok. I still wouldn't mind seeing your results on medium but please don't bother just for me.

Thanks for posting your results.

Mike