# Noctigon copper mcpcb mod for P60 setups (improving thermal pathway)



## LilKevin715 (Jun 30, 2013)

The benefits of direct LED to copper mounting is well documented here on the forums. Copper mcpcb’s without a dielectric layer such as the Sinkpad or Noctigon do help tremendously in allowing LED’s to be overdriven. Overdriven LED’s means more heat and that heat needs to be transferred to the body of the flashlight host in an efficient manner. 

P60 setups typically use a brass pill, which is a bottleneck in terms of thermal conductivity compared to the rest of the metal used in the thermal pathway to the body of the flashlight host. Brass has roughly half the thermal conductivity of aluminum, while copper has roughly twice the thermal conductivity of aluminum. Disregarding thermal interface materials such as thermal paste and epoxy the thermal pathway of a P60 setup is:

LED -> MCPCB -> Brass Pill -> Aluminum Reflector -> Flashlight Host

If the Brass pill is a bottleneck what can be done? There aren’t any widely available pills made of better materials such as copper or aluminum. Here is my solution.



 

 

My mod helps transfer heat from the copper mcpcb to the aluminum reflector directly without going through the brass pill. The amount of surface area where the small copper strips come into contact with the reflector isn’t that great, but it’s definitely better for heat transfer than going through the brass pill. Heat will still be transferred to the brass pill, just not as much as before with a regular setup.

Here is how I did the mod. First step is to scrape away the dielectric layer of the mcpcb on the edge and to determine how thick the dielectric layer is.



 

 




 


1.58 – 1.3 = 0.28mm thick dielectric layer

Next up is to measure the distance to be bridged between the mcpcb and the reflector. FYI I used a Fasttech XP SMO reflector (SKU 1208506).



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Distance between the reflector and mcpcb with dielectric layer: 4.84 – 3.6 = 1.24mm
Distance to be bridged by copper strips: 1.24 + 0.28 = 1.52mm

Here are the copper strips for the mod that were from a piece of copper pipe. I filed them down just a tad bit too much (0.07mm), but in the end it worked out just fine.



 

 


Copper strips and LED reflowed onto the mcpcb. The reflow process added 0.08mm in height between the copper strips and the mcpcb. The distance bridged by the copper strips + solder paste is 2.83 – 1.3 = 1.53mm. 



 

 




 

Here are some assembly pics of the dropin. Note the copper strips are above the top lip of the pill. Ceramique thermal paste was used between the mcpcb and the pill, while Fujik was used on the copper strips and on the threads of the reflector. Everything was screwed together tightly and allowed to cure/dry.



 

 



FYI the driver used is a Kaidomain v2 8xAMC7135 (3.04A). A XP-G2 driven at this level definitely needs a better thermal pathway; hence the reason for the mod to the Noctigon mcpcb being done. Last thing to do is wrap the dropin with some copper foil and I’ll be good to go.


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## badtziscool (Jul 1, 2013)

Very nice! Is this a one-off creation or do you plan on doing a production run with this?


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## LilKevin715 (Jul 1, 2013)

Its most likely a one-time creation, more of a proof of concept/prototype idea. If I do make anymore it will be for myself as I am using the human lathe method for construction: metal snips and lots of metal filing by hand. If I had a lathe it would reduce the amount of time significantly to create the copper strips. Heck if I had a lathe I wouldn't bother doing this mod in the first place; I would be making P60 pills out of copper instead.


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## zoom (Jul 2, 2013)

To tin Noctigom or SinkaPad directly in to the small copper strips from the back side should be much easier


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## LilKevin715 (Jul 3, 2013)

zoom said:


> To tin Noctigom or SinkaPad directly in to the small copper strips from the back side should be much easier



:huh2:
That sort of defeats the purpose of the mod:* improving the thermal pathway to the host*.


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## LilKevin715 (Jul 14, 2013)

I've finally got around to doing some testing to see how effective the mod is. For testing I compared three different XP-G2 dropins as I've built as listed below:

XP-G2 R4 4C @ 1.7A with Aluminum mcpcb
XP-G2 R5 3D @ 2.4A with Noctigon mcpcb
XP-G2 R5 3C @ 3.04A with Modded Noctigon mcpcb

The output of each dropin will obviously be different. What I am more interested in is output loss over time. FYI Each dropin is built in the same manner (Fujik on the reflector threads, reflector wrapped with copper foil) with the main difference being the mcpcb used. To measure output loss I used my lightbox (details here) and took measurements every 30 seconds in a 5 minute runtime test. I did not run the test longer than 5 minutes as the lights were not cooled externally in any way (no fan for airflow).

Here are the test results (click on the images to enlarge). Lux readings from my lightbox have been converted to Lighbox Lumens (LBL for short) and the percentage loss from initial turn on has been calculated.



 

Here is a graph of the LBL loss percentage over time of the three different mcpcb setups.



 

Output of all three mcpcb setups sags the most in the first minute of runtime, which is to be expected. After the first minute of runtime looking at the data and graph we can see two trends. The Aluminum and Noctigon (unmodified) mcpcb setups continue to loose output as time passes by. However the output of the modified Noctigon mcpcb setup levels off. This can be attributed to the better thermal pathway of the noctigon mcpcb mod; heat is transfered faster to the body of the flashlight host. If the runtime test was longer the output of the modified Noctigon mcpcb setup would have most likely sagged more eventually. 

So to answer my own curiosity the mod definately helps. Visually I can't tell a difference, but that is why I tested output with my lightbox.


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## bshanahan14rulz (Jul 15, 2013)

Even if visually you can't tell a difference, this is just a testament to these modern LEDs. Really, it is good to know that you've done it right, and that your LED is happier than it would have been otherwise. Thanks for following up and providing your data and conclusions


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## Walterk (Jul 16, 2013)

Nice graph! Thx for the demonstration.


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## Chodes (Jul 21, 2013)

Well thought out and executed.


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## D2000 (Jul 21, 2013)

Great proof of concept! Thanks for the data.. I love it - science and experimentation purely for knowledge sake


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## clemence (Aug 7, 2013)

Guys,

Today the marketing in Sinkpad sent me an email. I can't find a direct page to show you. So, I'm attaching the screenshot.
Sinkpad is now gen II! They now have flat bottom, no cavity underneath and what I like the most: they offers BENDABLE MCPCB

here's the screenshot from my inbox:


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## tobrien (Feb 7, 2014)

so I googled "noctigon" and this thread showed up, but who exactly makes Noctigon? Is it the same as the Sinkpad stuff?


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## Mattaus (Feb 8, 2014)

Noctigon are made exclusively for intl-outdoor, although intl-outdoor resell through a handful of other shops. I think noctigons are better than sinkpad though the new sinkpads seem to be similar now.

Sent from my Galaxy Nexus using Tapatalk


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## Mr. Tone (Feb 8, 2014)

Help me out here guys but what would the benefit be of being "bendable"? Wouldn't most placed you would mount an LED be milled flat?


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