Courui Big Head COPPER heat sink feeler. Let me hear your voice!

Hey all,

I have not yet seen any thread where another member is offering a full run of these, only the thread were a single pill was sold. If someone is already doing this I may just bow out :)

Here is the light we will be talking about in this thread. Its an amazing light with endless possibilities.

Here are my thoughts on this.

Option one
Keep it very very simple (and cheap)

I take one of the 100+ dollar per foot sticks of 1.75" copper rod and turn a piece that looks like this.

The dimensions are rough at this point but the picture gives you an idea what I mean.

This would be the simple cheap way of going. There would be NO threads, NO led recess, NO driver slot or wire holes. This would give the user the full benifit of a massive chunk of copper and exceptional conductivity with almost none of the cost of intricate machining. The flat top would also give the user full range of flexibility for MCPCB size ie 20mm 32mm etc.

The sink would be held down by either pressure from above by the reflector, or by epoxy.

Doing it this way will GREATLY REDUCE THE COST.

I am thinking cost per unit this way will be about $14 each.

Option 2

We go with a full blown production model. This version would be a thread in. Have a recessed pocket for a 20mm star and have pre drilled wire holes. The sink would still be a flat bottom since most people are using the factory driver. This lowers the cost per unit by about $6-7

Price for this version would be about $38 each

Option 3

Yes threads. Yes wire holes, but pushed out to the edge at around 31mm mark. NO Led pocket

Price would be $26.50 each

Shipping would be $4 USA and $7 world wide.

Please chime in and let me know your thoughts on this :)

What about no pocket with option 2? The reflector gets close to the solder points on the 20mm and prevents thick wire.

Yes I also would like option one with threads…if the threads are always the same on every model…
I have a 31.5mm maxtoch copper mcpcb laying here for use in the courui so no pocket would be the best…

Yes of course some edits can me made at this point. This is exactly why I wanted feed back on the design.

The only caveat with leaving out the pocket for the LED on the threaded version would be that the wire holes may need to be left out. Without the led pocket it would be tough to align the holes properly ( I dont have a mill), but since many people would be using a different size MCPCB anyway I think it may be better for the individual to place their own holes anyway.

How important are the pre drilled wire holes to everyone? Is it a deal make or breaker?

Please let me know YOUR opinions WILL effect the design. I will do my best to take into account what everyone has to say.

EDIT: Werner do you know if the maxtoch copper boards are a direct bond to the base like sinkpa or noctigon? The reason I ask is I have some copper boards from china that are just copper but still have the substrate layer.

What about wide wire holes for the bigger boards? These could still be used for smaller mpcbs…?

To drill a hole in copper can be tricky and break a drill bit easyly…I would say if it is possible without major increase in effort and cost it would be a good thing.

The maxtoch are dtp, I have not used one yet but they are sold as dtp and they have conductance from the center pad to the bottom. The only tricky thing is that they come with a clear protection film, which could cause problems if you don’t notice it. Link with description

I am in for one for sure :slight_smile:

If everyone is ok with that I would also agree to it. I see no reason why having the holes out to the side would hinder anyone who wanted to use a smaller MCPCB with this light.

I will add an image to the op to represent this as a 3rd option.

I would love to get the one with thread in aluminum.

Always this goddamn expensive copper… some of us don’t want to drive a XP-G2@6Amps in there, just want a proper heat-sinking.


BLF rule #2, thou shalt not swear (or otherwise be rude crude or socially unacceptable)

The option one looks very viable, leaving a lot of room for leeway.

Has it been discovered if the threads in these D01’s are of a consistent nature? Would a threaded insert be likely to cause issue? It would certainly open some options for mounting different emitters and achieving accurate focus…

Threaded but with a flat surface and holes on the outer edge would be my way of thinking. Will have to open mine up and have a look for these specifics to see what might be most applicable.
Thanks for checking into this.


Sure aluminum would be a possibility. It would certainly cut the cost a bit. If others seem to be on board I would consider that as well.


I suppose I could spin of a sample and pass it around if needed. I do have a pair of these lights in hand at the moment and I will check the threads on both.

My only other concern with a threaded flat top is this. In order to get the threads to come up high enough on the wall to be useful, there would still have to be a counter sink made for the emitter even if it was near the edge. Other wise the emitter sits up too high. I took that little plate thing that came in one of mine and flipped it over. The height was ok, but when I screwed it in NONE of the thread were in use. When it bottomed out I could spin the plate in circles.

I’d be in for option 3, aluminum if it was available, copper if not.

I'd lean towards option 1, then. It's more adaptable if the manufacturer decides to use different threads on the grey ones, or something. Costing 60% less doesn't hurt, either.

I would like the cheaper option #1 in aluminum also - just my 2 cents Smile. I know we have proven the copper MCPCB is the biggest factor, and maybe comfy's position has some merit after the MCPCB.

PS just ordered a bunch of copper discs of assorted sizes from Bopper on Etsy ( -- quoted me a price on exact sizes/qty I wanted. She offers pretty much the same options in copper and aluminum, but comparing the prices (18 gauge to 18 gauge), it's only about 12% more for copper, so I'd rather buy copper because I can solder the discs together and make a bigger heat sink out of it, or solder directly into a brass pill - I can't do that with aluminum discs. Only problem is the extra weight of copper vs. aluminum.

For a big heat sink like this, I'm thinking the material cost of copper is considerably more - all depends of course...

the price for the unthreaded version is what is so tempting…

Alu would be also nice for me if it considerable cuts cost…but of course a shiny copper piece is nice to have.

I just have looked again at Linus thread in post #71 he noted some measurements which will help to imagine the circumstances better: Teardown and Mod Thread of Courui XML2 Aka "Big Head 3x18650 Side-Switch Thrower"

If anyone is interested Mountain electronics has the 31.5mm Maxtoch XM boards for what I thought was a very reasonable price.

IF these perform like sinpad/noctigons I may consider assuming use of them in the design. I have some on the way.

Nice boards, and DTP. The contact pads are way on the outer edge, making it easy to clear most reflector bases.

The 25mm board that I got doesn’t have anything on it, but the larger 31mm board has a thin clear protective film over it that of course must be removed prior to use.

I would take two of the cheap ones. I would want to drill my own holes anyway and using a really good thermal epoxy to set the pill in place will work just as well as threaded anyway.

Ya know, in the back of my mind I was thinking to myself, "what would I do if I was only making the batch for me?"

I think the answer is leaning more and more toward this. Just an aluminum sin with some good mass. Go super BLF on the deal and cut the price as deep as humanly possible..

Especially with the use of a large copper MCPCB (31mm) I think the heat is being "conducted" excessively well already. Once its pulled from the emitter and spread out the next step is to dissipate it right.

Option 4?? The BLF EXTREME??

Just the T shaped sink like in option one, but made from aluminum.
Optional pre drilled holes for couple bucks more fore the people who want it?

Like $8.50 maybe?
Pre drilled holes add $5

+1 VOB! Smile. I got a bunch of your copper pills, and some others. I think the mass is great - well over stock, but not so sure of the copper vs. alum. The weight of these lights is considerably more than stock - gives them a quality feel but the weight is just that more to lug around. I think a well designed alum heat sink would work maybe just as well, or at least close. Don't think anyone has done, or published, any direct head to head comparisons in a real practical modded light, so I don't really know for sure. comfy has been implying alum is as good as copper - for me, I am tending to believe him more and more. Also it's just whatever is easier to work with, or what's available. I like that copper can be shaped, formed, and soldered of course.

But for this - made custom just for this light, and thinking can be mounted solidly, alum would be pretty darn good.