Teardown and Mod Thread of Courui XML2 Aka "Big Head 3x18650 Side-Switch Thrower"

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LinusHofmann
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comfychair wrote:

gords1001 wrote:
I wonder if the 5a ramping lck led driver could be peesuaded to fit? http://www.lck-led.com/38mm-side-switch-5000ma-driver-sst50-p-1102.html?... from the quoted size, I’d say so but it depends on the positive pcd. comfychair has one so perhaps he could give us a measurement to compare to the stock board?

I just retested this one with 3× 20Rs in parallel. It, well, sorta works. It’s not entirely happy with the voltage, it makes a truly wicked squeal from around 40% up to 80%. It’s fairly quiet at 100%, but still making some noise. It only sounds not too bad because of how loud it is before it gets to 100%.

Output is 4.10-4.15A, shorting the big sense resistor on the top board only bumps it up to 4.30A. It is much happier at 8.4v input and above, though I don’t think it would be unsafe/unreliable at 4.2v. The squeal is from the driver itself, not any of the connections or other components. No squeal at 8.4v.

How wide is the top circuit board? That may be the biggest hurdle to getting this to fit.

comfychair
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LinusHofmann wrote:
How wide is the top circuit board? That may be the biggest hurdle to getting this to fit.

1.31"/33.something mm.

The inside surface of the lower board has components out to within .070" from the outer edge, so the ledge the driver sits on can't be any wider than that.

janko.hrasko
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I love this beast Smile
on the left is the big head with dedomed stock emitter flowed onto noctigon, replaced wires, braided springs, r100 sensing resistor and smaller centering plastic
on the right is t08 dedomed xm-l u2 1c on noctigon, replaced wires, some resistors stacked up..
and damn! this thing throws Smile

also I turned the emitter plate upside down to be able to focus better (get the led deeper into the reflector and create some pressure on the board) and pasted it a little – then tightened it really well
but I screwed up the stock driver a bit, it doesn’t turn completely off Sad measured ~16ohms between L- and ground and couldn’t find where was it coming from Sad oh well, it’s a nice nightstand light when “off” Big Smile

LinusHofmann
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good to see some more of these lights in the hands of modders!
The hotspot it produces really is very nice once focused, dedomed it must be a beast. Nice one!

Did you manage to get a reading of tailcap current after the r100 resistor change?
Cheers

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not yet, I’ll try to get a good reading this weekend across the tailcap
the hotspot is really nice, with a bit of flares
it got a brighter ring around the hotspot but that doesn’t bother me that much and I will not mess with the focus no more

Rod911
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janko.hrasko wrote:
I love this beast Smile on the left is the big head with dedomed stock emitter flowed onto noctigon, replaced wires, braided springs, r100 sensing resistor and smaller centering plastic

Pretty much what I am planning to do with mine. The XP-G2 version will be using either an R120 or R150 resistor. I am not entirely too sure yet.

How are you finding it handling the added heat? Do you think it’s necessary to add some more heatsinking mass to the LED plate/shelf?

LinusHofmann
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Rod911][quote=janko.hrasko wrote:
Do you think it’s necessary to add some more heatsinking mass to the LED plate/shelf?

On my light I would say yes it’s pretty much necessary for higher output. Definitely for overdriving an XML to the max. Maybe not for XPG but the stock solution is really not ideal.
janko.hrasko how was the tolerance of the pill shelf threads on your unit?
Mine was very loose, as in I could wiggle the shelf easily and by quite a large amount when it was partially threaded on and in the focus position, that’s the worst thing about the thermal transfer I think. Very few threads for a small contact surface, and loose as well. Putting thermal grease/paste on the threads helps but not enough really.

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the shelf was very loose on mine in the focus point too.. that’s why I flipped it upside down to tightly screw it against the rim underneath it
in stock there was a recess in shelf in which the led was sitting.. now it’s higher on the flat part of the shelf and even the reflector is pressing on it from the front
the heat transfer seems fine to me, it’s getting pretty warm but not hot even when I’m not holding it – the whole massive body is working as a heatsink

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janko.hrasko wrote:
the shelf was very loose on mine in the focus point too.. that’s why I flipped it upside down to tightly screw it against the rim underneath it in stock there was a recess in shelf in which the led was sitting.. now it’s higher on the flat part of the shelf and even the reflector is pressing on it from the front the heat transfer seems fine to me, it’s getting pretty warm but not hot even when I’m not holding it – the whole massive body is working as a heatsink

Yeah nice idea to flip it over, that’s probably going to result in the best solution using the stock components! Smile

Rod911
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Is there any chance you can take measurements between the bottom of the LED shelf once it is screwed in and the top most driver components? It looks like the clearance is around 30mm, but that is a total guestimate.

LinusHofmann
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Rod911 wrote:
Is there any chance you can take measurements between the bottom of the LED shelf once it is screwed in and the top most driver components? It looks like the clearance is around 30mm, but that is a total guestimate.

Sure, I’m stripping the light down again in a bit so I’ll take a bunch of internal measurements of everything

Ok here is what I came up with.

top of emitter shelf from top of heatsink when in focus ~2.7mm
thickness of emitter shelf 3mm (3mm-0.85mm for pcb cutout)
-
depth from top of driver board to emitter shelf rim 27.5mm
depth from emitter shelf rim to electronic switch port ~12mm
driver cavity inner diameter 34mm (33.98mm)
-
emitter shelf thread O/D 41.75mm
I/D of emitter shelf threads in body 41mm
depth of emitter shelf threads in body 7mm
-
thickness of driver board 1.6mm
height of driver at highest component (including board) ~12mm
-
diameter of flat base section on reflector 27mm

So Rod, if you want to know exactly the distance between the bottom of the emitter shelf when it’s focused and the top of the driver board.

It’s…

distance from top of the driver board to emitter shelf rim (27.5mm) + depth of emitter shelf threads (7mm) – gap from top of threads when emitter shelf in focus (2.7mm) – thickness of emitter shelf itself (3mm).

And if I didn’t mess any of that up it comes out as 28.8mm, so your guesstimation was pretty damn close Smile
If you’re wondering about the size of the copper slug you could fit in there though, you’d have to take into account the height of the toroid on the driver (around 11mm) and the electronic switch port which is only 12mm down from the edge of the emitter shelf rim.

-

Easiest heatsink enhancement I think would be a 34mm X ~13.5mm slug (copper/aluminium) lapped and bolted to the bottom of the emitter shelf. Then drilled to accomodate the two emitter wires.

Starting with a 35mm bar it should be fairly easy to sand the O/D down a bit and also remove the anodizing on the inside of the driver cavity walls (and open it up a bit as well) to get the combination close to being a press fit.

At least that’s what I’m going to be attempting I think, I have 35mm aluminium bar stock at hand and it should be doable without heavy machinery…I hope Silly

Better would be to machine a whole new pill out of copper with threads and everything but that’s definitely out of my league, and I’m pretty sure a lathe is mandatory for something like that… Wink

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Many thanks for the info. I am hoping the heatsinks which I ordered from FT arrive within a couple of weeks. A copper slug of around 10mm in height might do the trick if I can find said slug in a hardware store.

Thinking out loud, the plan is to place the LED shelf upside down. With it upside down, the area where the LED is supposed to occupy, there will be a 20mm copper slug in its place. The surrounding area, I will place heatsinks which are 5mm in height. I will have to rely on the threads to transfer the heat collected to the body.

Also, with the shelf upside down, it should focus the LED better as suggested by janko.hrasko as it is sitting up closer to the reflector rather than the default position.

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Rod911 wrote:
Many thanks for the info. I am hoping the heatsinks which I ordered from FT arrive within a couple of weeks. A copper slug of around 10mm in height might do the trick if I can find said slug in a hardware store.

Thinking out loud, the plan is to place the LED shelf upside down. With it upside down, the area where the LED is supposed to occupy, there will be a 20mm copper slug in its place. The surrounding area, I will place heatsinks which are 5mm in height. I will have to rely on the threads to transfer the heat collected to the body.

Also, with the shelf upside down, it should focus the LED better as suggested by janko.hrasko as it is sitting up closer to the reflector rather than the default position.

The problem with this approach is you’re not really doing much to improve the thermal path away from the shelf and to the outside. It will work well initially to suck and store heat from the led but the real weakness of the shelf is not really it’s thinness but that it can only transfer heat to the body through it’s small and loosely machined threads with minimal contact surface. Upside down or not the contact area is still pretty minimal and that will be the main bottleneck.

The idea with adding a 34mm slug that fits down into the driver cavity is that this will both collect and transfer the heat out along it’s own contact points to the driver cavity walls. Even if the press fit isn’t optimal you can increase/improve the contact area very easily with a few layers of copper or alu foil.

I’m pretty sure that will do a much better job at keeping the led cool than relying solely on those threads on the emitter shelf. You’ll see when you get the light, they’re pretty suboptimal…to put it kindly. :bigsmile:

Incidentally how easy/hard is it to remove anodizing on a specific part of a light without destroying the rest. Like could I paint on the degreaser/greased lightning only to the inside of the driver cavity and let it do it’s thing or would just sanding the coating off be a much better idea?

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LinusHofmann wrote:
Rod911 wrote:
Many thanks for the info. I am hoping the heatsinks which I ordered from FT arrive within a couple of weeks. A copper slug of around 10mm in height might do the trick if I can find said slug in a hardware store.

Thinking out loud, the plan is to place the LED shelf upside down. With it upside down, the area where the LED is supposed to occupy, there will be a 20mm copper slug in its place. The surrounding area, I will place heatsinks which are 5mm in height. I will have to rely on the threads to transfer the heat collected to the body.

Also, with the shelf upside down, it should focus the LED better as suggested by janko.hrasko as it is sitting up closer to the reflector rather than the default position.

The problem with this approach is you’re not really doing much to improve the thermal path away from the shelf and to the outside. It will work well initially to suck and store heat from the led but the real weakness of the shelf is not really it’s thinness but that it can only transfer heat to the body through it’s small and loosely machined threads with minimal contact surface. Upside down or not the contact area is still pretty minimal and that will be the main bottleneck.

The idea with adding a 34mm slug that fits down into the driver cavity is that this will both collect and transfer the heat out along it’s own contact points to the driver cavity walls. Even if the press fit isn’t optimal you can increase/improve the contact area very easily with a few layers of copper or alu foil.

I’m pretty sure that will do a much better job at keeping the led cool than relying solely on those threads on the emitter shelf. You’ll see when you get the light, they’re pretty suboptimal…to put it kindly. :bigsmile:

Incidentally how easy/hard is it to remove anodizing on a specific part of a light without destroying the rest. Like could I paint on the degreaser/greased lightning only to the inside of the driver cavity and let it do it’s thing or would just sanding the coating off be a much better idea?

flipped shelf isn relying solely on those poor threads.. it sits tightly on the rim and with some thermal paste there it isn’t that bad Smile
sure copper pressed really tight would be better but I don’t think that it matters to me that much to have someone machine it for me

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Hi Linus,

Thanks for the review.   

Can you tell me what the outermost diameter of that heat sink plate the LED sits on is?

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vestureofblood wrote:

Hi Linus,

Thanks for the review.   

Can you tell me what the outermost diameter of that heat sink plate the LED sits on is?

Sure, that’s what I’ve called the “emitter shelf thread O/D”, probably could have named it better. It’s 41.75mm.

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I got tailcap lockout!
just unscrew the tailcap, unscrew the b- pcb, take it out
screw the three screws that were holding it to the body

place the pcb OVER the screws

get something that can create pressure on the pcb from the tailcap (I used a lid from film canister) and place it over the pcb

screw the tailcap on and BAM! Smile
when you tighten the tailcap, it pushes the pcb on the screws and completes the circuit
loosen it a bit and the pressure from the springs breaks the contact

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Nice and simple, good job! Smile

Update: I ordered a custom firmware driver from DrJones (mokkadrv – 4 mode) that I’ll be using in this light.
Probably won’t do much work on it till I get this driver, too many projects on the go and I really need to get my BTU-MTG2 monster project finished up. Smile

But I’m keen to see what others are coming up with in the meantime so feel free to post any progress or ideas in this thread so we can have a collection of useful info on this light.

If anyone has any questions or wants any measurements let me know, the light will stay disassembled for now.

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Linus. I’ve just encountered the same type of threaded emitter plate on the Yupard I started working on. The COURUI has an integral ledge that the plate threads down onto, but mine doesn’t. I can’t add extra heat sinking that will transfer heat into a ledge that is part of the head.

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Ouchyfoot wrote:
Linus. I’ve just encountered the same type of threaded emitter plate on the Yupard I started working on. The COURUI has an integral ledge that the plate threads down onto, but mine doesn’t. I can’t add extra heat sinking that will transfer heat into a ledge that is part of the head.

Looks like the shelf threads in the body are also anodized on that Yupard, that can’t be helping thermal transfer surely.

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I’ve got an idea! I’ll let you know if it pans out.

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Allegedly, anodizing doesn't affect the thermal properties in a significant way. It might be measurable, but that doesn't mean much. If your wife says 'it's cold in here!' and you raise the temp from 63.4* to 63.8*, that's measurable, but probably not likely to do anything to stop the complaining. Smile

A change in output of 1 lumen is measurable, but how much work would you be willing to invest for one lumen? How many lumens would an improvement have to be to be worth whatever work required to get it?

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Just placed a order for 2 cant wait Smile

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comfychair wrote:

Allegedly, anodizing doesn’t affect the thermal properties in a significant way. It might be measurable, but that doesn’t mean much. If your wife says ‘it’s cold in here!’ and you raise the temp from 63.4* to 63.8*, that’s measurable, but probably not likely to do anything to stop the complaining. Smile

A change in output of 1 lumen is measurable, but how much work would you be willing to invest for one lumen? How many lumens would an improvement have to be to be worth whatever work required to get it?

Sure, I’m just suggesting something that could potentially improve a poor heatsinking solution.
I bet even small changes in thermal conductivity at the interface will have some effect when the contact surface from a loosely threaded emitter shelf is already minimal.
I don’t know how hard it is to remove anodizing though so it may not be worth the hassle, maybe the same benefit can be had by just slapping some thermal paste on the threads instead…

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Removing the anodizing won't improve anything, as it's not a hindrance. It's not one of those little things that when combined with a bunch of other little things adds up to something meaningful, it just doesn't affect it one way or the other.

Now, an anodized outside surface has better radiative properties than bare aluminum, but for internal parts it doesn't matter.

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I got my COURUI today. Eleven days. Wow! I really like the look and feel of this light. Now I have to decide what I’m going to do to it.

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I’m getting a reading of .290A accross the tail on high. What am I doing wrong?

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Ouchyfoot wrote:
I’m getting a reading of .290A accross the tail on high. What am I doing wrong?

Did you remove the filament wire before taking the reading? Silly

How’s the output of the light in general, you’d notice if that was the actual drive current. Would be very dim.

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No, I didn’t remove the filament. I just placed my probes on each end.
It was bothering me, so I took an emitter reading… 2.22A. Man, those wires sure are microscopic. The light throws great. I only tested off my balcony, but it went through a dark area, accross a highly lit street and lit up a dark alley on the other side.

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Ouchyfoot wrote:
No, I didn’t remove the filament. I just placed my probes on each end.

Well that’s the problem, you’re only reading a fraction of the true current like that. The majority is still going through the wire and not being measured!
For accurate current readings your DMM needs to be in series with the circuit without any other conductor in parallel.

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