Oh, I think the S6 did a very good job, being limited to an aluminum heat sink. They were both so hot I could barely pull the tail cap off after 5 minutes. But look, the L2m did it with a considerably smaller lesser cell! Copper, my friend! The C8 trifecta proves it out, my Cu M8 proves it out. Whether at 3A or 10.5A, copper does your body good, pass it on… 
Looking to buy: One chunk of sweet copper.
Bucket is the Cu go-to guy. Fast, excellent workmanship, and reasonably priced. He da man!
OK, not doing lights for anybody but me from now on. Dale, until your chart shows battery voltage alongside the light output, you're only seeing half the picture and pretending like the other half doesn't exist. Have fun guys.
I didn’t say the light you build was bad in any way, it just has limitations due to it’s size and whether or not copper would make any difference at all I simply do not know. Yeah, I could put my light engine in an L2P and run it with an 18650 20R so they’d be apples to apples across the board. Not much point in setting up to read voltage or amperage or anything else, as they are flashlights, handheld tools to chase darkness away and that’s how I approach em. When the power goes off, how long is it going to do what it does? All that matters to me, doesn’t even matter which one does it better or longer, I’ll just grab another when those cells die. No biggie.
Your end of the S6 is gorgeous, nothing wrong there at all. Already told you that.
For those who were thinking about grabbing the new 2x26650 host here is a little write up I did; It shows how well the dry driver and MT-G2 fits in it
Build Using New Host from Mountain Electronics
Well I don't understand at all then. You claim your data proves something, then say it doesn't matter. The light output is only the end result of temperature, input power, and output power. It tells you less than nothing about the pill material.
Some people are always going to believe that copper is a substance infused with pure magic that causes heat to evaporate away into a parallel universe, I guess I'll have to work on accepting that I can't fix irrational beliefs.
I only know what I read in the forum, and I assumed that copper is superior in delaying heat sag.
Copper is a better conductor of heat than aluminum but aluminum radiates heat faster than copper due to its lower density.
Other words copper pulls heat off faster than aluminum but aluminum radiates heat to ambient temperature faster than copper.
It converts heat into that dark energy they can’t ever seem to locate? :bigsmile:
Much the same way that while solder has not very good thermal properties it still is able to work well because the layer of solder is so thin, the pill-to-head/body contact area is so much greater than the area where the heat comes from (LED's center pad) that even a relatively poor material is able to work not much different than a really good material.
Why do copper MCPCBs work better than aluminum MCPCBs? Is it because they're made of copper? Or because the dielectric layer can be eliminated since copper can be readily soldered to using non-exotic solders & flux? If it were possible to solder a LED direct to an aluminum board without a dielectric layer, I'm pretty sure there would be no performance advantage to using copper and copper boards wouldn't exist because there'd be no reason for anyone to invent them. Again, compare the contact area between the LED center pad and the MCPCB, and the contact area between the MCPCB and the pill.
SinkPAD makes both aluminum and copper direct thermal path stars. I have a couple of the aluminum ones, though never did a head to head. I believe their site has test results. I thought recalling it was pretty clear the copper was superior, just the aluminum was offered for reduced cost and weight, but still the SinkPAD aluminum was better than the 10 cent aluminum stars in most flashlights.
q = k A dT / s (1)
where
q = heat transfer (W, J/s, Btu/s)
A = heat transfer area (m2, ft2)
k = thermal conductivity of the material (W/m.K or W/m oC, Btu/(hr oF ft2/ft))
dT = temperature difference across the material (K or oC, oF)
s = material thickness (m, ft)
I don’t have a dog in this fight, but I thought long ago that CPU heat sink makers had already settled this discussion about what works best. Copper to absorb it and aluminum to dissipate the heat with a press fit between the two.
When I say press fit I don’t mean a fit where the copper cylinder maybe .001” smaller than the hole and it has to be drove in. A press fit is a fit where the cylinder is actual a very tiny bit larger than the hole or the exact same size, no air gap. It must be forced into the hole sometimes using heat and cold temps.
Seems like I remember that too 007 and I’m currently asking about making some changes to the big copper pill on my M8. I see what is being said, there’s 2 sides to it, as with most things, and there’s compromise. So I’m willing to put some greenbacks on that argument and have a copper core pressed into aluminum fins, the copper to pull mass heat and the aluminum to disperse it. And more of everything. Dissipating the heat from an MT-G2 at 10A is a large order. Results are what I crave, regardless of the science that achieves it.
1+ :bigsmile:
Copper for thermal conduction, aluminum for convection. Anodized contributes higher emissivity then bare. Don’t polish your lights.
That’s what I said in post #957
moderator007 understands H)
um… you know we don’t have to hijack a great seller’s thread, we could open up another thread exchanging this idea and whatever kakameme scientific proof you guys have… let’s keep this thread clean and concentrate just on what’s the latest awesome stuffs on Richard’s store and maybe give a little guidance for some newbies who wants to build an awesome light 
Pretty sure that as a salesman RMM doesn’t mind one bit that we keep this thread on top!
I need some more CREE XM-L2 U2 1A LED on Noctigon 20mm MCPCB and Panasonic NCR18650PF 2900mAh Button Top Unprotected batteries 