Aluminium foil wrap effectiveness - measured data

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rennsman
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Aluminium foil wrap effectiveness - measured data

I took these measurements in 2009 and posted them on CPF, I thought I may as well post them here as well. 

The idea was to see how effective wrapping the drop in pill with aluminum was in regards to thermal control was, as you will see quite an appreciable difference in temperature was measured. 


Using a Solarforce L2R2 flashlight, I measured with a beaded type thermocouple the temperatures of some areas on the torch, and graphed these against time.

Position one, the side of the led's own plastic lense.

Position two, the deepest point of the pill's reflector.

Position three, On the top of the LED's own reflector, the alloy rim that you can see around the led lense.

 

 

L1

 

l2

Edited by: rennsman on 04/23/2012 - 09:40
Don
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Thanks for this.

 

Bet this test was a pain to do.

 

The numbers from my light tests are always to be found here.

https://spreadsheets.google.com/ccc?key=0ApkFM37n_QnRdDU5MDNzOURjYllmZHI...

Pulsar13
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Wow... around 10°C difference on LED side. That is really something. Thanks for doing this, finally we have some data to back the aluminium wrapping theory.

BetweenRides
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I'm not sure I understand the middle one... It seems by your graph the temperature went up when wrapped. This one seems to be opposite of the other two measurements. Are the two labels mixed up or am I reading this wrong? (Yellow and Light Blue lines)

Lothar
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Very good results! Thnx for sharing!

Current Collection:

BLF: BLF-GT90, BLF-GT70 (CW Sliced), BLF GTmini, BLF-LT1; 

BTU: Shocker (3 x SST-40 @ 8A)

Solarforce: L2P (XM-L2 U3 @ 4A), MPP-1 (XP-L HI @ 6A), MPP-3 (3 x XM-L2 U2 @ 12A), M6 (Nichia 319A @ 6A), M8 (XHP-50.2 @ 9A), 9x (9 x XM-L2 U2 @ 2A)

Coming Soon: Lumintop: BLF-GT4; 

rennsman
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BetweenRides wrote:

I'm not sure I understand the middle one... It seems by your graph the temperature went up when wrapped. This one seems to be opposite of the other two measurements. Are the two labels mixed up or am I reading this wrong? (Yellow and Light Blue lines)

You are right, I never noticed my mistake, I will swap the colors over.

Thanks.

Lothar
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I know this is a very tall order/request, but is there any chance you can perhaps repeat the test for a XM-L running at 3A at some point in the future? Laughing

Current Collection:

BLF: BLF-GT90, BLF-GT70 (CW Sliced), BLF GTmini, BLF-LT1; 

BTU: Shocker (3 x SST-40 @ 8A)

Solarforce: L2P (XM-L2 U3 @ 4A), MPP-1 (XP-L HI @ 6A), MPP-3 (3 x XM-L2 U2 @ 12A), M6 (Nichia 319A @ 6A), M8 (XHP-50.2 @ 9A), 9x (9 x XM-L2 U2 @ 2A)

Coming Soon: Lumintop: BLF-GT4; 

BetweenRides
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NP, rennsman. Thanks for a great test.

JohnnyMac
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Lothar wrote:

I know this is a very tall order/request, but is there any chance you can perhaps repeat the test for a XM-L running at 3A at some point in the future? Laughing

+1

Nice work, Rennsman!!

spectrrr
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Nice work Rennsman, very useful!

Since all three measurement points showed roughly the same separation trend (wrapped vs non wrapped) after a few minutes, we could probably save time on future measurement tests and just measure a single point, at least for the purposes of comparing real world efficacy of a heat synching material.

I'm curious if the foil wrap would be more effective with a very THIN thermal potting material or any other such thermal goop (maybe a bulk sized tube of the really cheap CPU grease) that took up the air space between each layer of foil. Of course it would be a royal pain in the ass to do that, maybe more feasible with a thicker material like thicker copper sheets or pop cans, foil could have a lot of layers to it unless the pill fit very well already...

trooplewis
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I'm curious if you have gathered the same data with copper foil wrap?

Rats, finally sold my 2010 509hp Mustang...now I can buy more lights!

Sold the red one too! Now guess what I drive, doing my penance for 500 hp commuters...

http://dreammustang.com/

http://i884.photobucket.com/albums/ac47/Ha

rennsman
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Lothar wrote:

I know this is a very tall order/request, but is there any chance you can perhaps repeat the test for a XM-L running at 3A at some point in the future? Laughing

 I don't currently have a 3A drop in, however I wanted a P60 for one of my L2's anyway, so yes I will do this at some point, just don't hold your breath waiting. 

 

 

spectrrr wrote:

Nice work Rennsman, very useful!

Since all three measurement points showed roughly the same separation trend (wrapped vs non wrapped) after a few minutes, we could probably save time on future measurement tests and just measure a single point, at least for the purposes of comparing real world efficacy of a heat synching material.

I'm curious if the foil wrap would be more effective with a very THIN thermal potting material or any other such thermal goop (maybe a bulk sized tube of the really cheap CPU grease) that took up the air space between each layer of foil. Of course it would be a royal pain in the ass to do that, maybe more feasible with a thicker material like thicker copper sheets or pop cans, foil could have a lot of layers to it unless the pill fit very well already...

If you could apply thermal paste thinly enough it would probably help, I wonder if you could thin it down and spray it on? at least aluminum foil is a little malleable and when wrapped tightly has a slight chance of good contact between itself, though with each layer is an oxide surface which reduces heat transfer. 

I don't think it would be hard to overdo it with thermal past, as it itself is not that good a conductor of heat, it's just a lot better than the air gaps it is filling. 

Soft drink cans often have a plastic layer on the inside, you would want to remove this.

Copper sheet would most likely work very well, especially if you annealed/softened it, it should work better than aluminum foil.

The best thing would probably be a machined sleeve pressed onto the drop in pill and a tight fit to the host, then with some thermal compound.  

  

trooplewis wrote:

I'm curious if you have gathered the same data with copper foil wrap?

 

Sorry, I have not, I assume from your question that you know copper works better in this regard, though the trick would be using annealed copper for an easy install and good surface contact.

 

texas shooter
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I’ve wrapped with both and haven’t found much difference on my 3 amp dropins. Heat choke points have to be eliminated before any real difference in wrap material becomes apparent. Aluminum stars out copper stars in. Direct bonding of the LED, Copper pill over Brass. By the time you get to wrap material you have so much more surface area that the great copper heat transfers become negligible. How you wrap does matter, fewer thicker wrap layers work much better than lots of thin. I use larger soda can as the cans are thicker. Disposable Aluminum cookware is much thicker than foil and not prone to tearing. I’ve also used Aluminum tape, I think one or two adhesive layers transfer heat better than one or two air layers.

comfychair
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Calmaja
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Thanks for your effort rennsman.

sorotantaz
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when I use copper tape sheet, it gets hot faster than alu foil, afterward the feel is pretty much the same. no scientific data though. copper tape itself is thicker around twice than alu foil.