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

Ok cool thanks :slight_smile:

There's lots of promise if someone does a redesigned copper pill for this. Thanks for the teardown.

Thanks Linus - subscribed.

Hopefully my KD one will show up soon.

Yeah absolutely, plenty of space inside the driver cavity for some extra heatsinking mass and the threads in the head are considerably longer than the thickness of the shelf. Currently those threads make very poor contact to the emitter shelf.
I would definitely be interested in a copper pill for this light!

Ok I reassembled the light and I’m reading 2.58A across the tailcap “filament” attachment points on high.
Fully charged senybor 18650s reading around 4.16v after the test and it stayed stable at that reading for a good few minutes.

I didn’t take note of the reading on low because my meter doesn’t like the low frequency PWM current signal. It gives inaccurate averaging results.

I have 1 loose r200 (0.2 Ohm?) resistor of the same size as the one on the board and a roll of r500 and r100s but they are smaller, like half the size.
If I added the extra r200 in parallel to the sense resistor should I be seeing around 5.2A at the tailcap?

Cheers

Subscribed :slight_smile:

-Jamie M.

Ok another small update, just replaced the original tall centering ring with a nice flat one and as expected this has made the world of difference to the hotspot and beam profile.

The centering ring I used is one of those white plastic ones with the wings on both sides and not much more than a slightly raised section around the emitter square. It won’t work if the emitter is not already pretty much in the center and can take a bit of coaxing to lock the reflector down right in the center, but this is the type I’ve had the best luck with centering HD2010 reflectors and it’s worked superbly again here.

The emitter is now sitting almost completely flush with the flat shelf of the reflector and it’s now pretty much perfectly focused. The spot is really nice, even and tight with fairly sharp defined edges. I’m sure that’s the perfectly smooth finish of this reflector that’s providing the definition.
It’s much more defined in fact than a nicely focused HD2010 and the spot is about 20% smaller.
So yes this light will out throw a HD2010 if given the right treatment :slight_smile:

Here is a direct side by side comparison between my best HD2010 running at over 5A on copper and the Big Head running at the measured tailcap current of 2.6A. I think I need to measure emitter current because this thing is keeping up with and maybe already surpassing the HD2010 in perceived lux! :stuck_out_tongue:


Distance to wall is 2.5m, Bighead on left and HD2010 on right.

Such a shame it didn’t come like this, would be so much easier to recommend if the beam profile was nice right out of the box…

Wow, talk about flawless beam!!

Subscribed for outdoor beamshots :slight_smile:

-Jamie M.

Thanks for the tear down. Great pics and summary of the light. Now I don’t have to do it myself - just the build log. :slight_smile:

I am slightly disappointed with the visible PWM, as I would like to use the existing driver. It is good to know that there is enough space in there to use my own driver though down the track.

Regarding the resistor mod, from the LD-29 thread , if you were to simply replace the R200 resistor with an R100 resistor, you should see an immediate double in current going into the LED. I plan to do this for the XM-L2 version light I will build. For the XP-G2 version, I plan to stack three R120 resistors and put them on top of the existing R200 to get around 4A from the tail cap. Both lights I am building will be de-domed.

Note that, the above figures are using your own numbers. To reduce resistance throughout the light, I intend to use higher gauge wire in place of the existing wires, along with copper braid the springs, as you have suggested.

edit: I am hoping that this light can dissipate the heat coming from XP-G2/XM-L2 being driven at >4A.

edit 2: just looked at your pics of the pill again. Man, is there a lot of space in there. Thinking out loud, me thinks soldering copper on the bottom of the pill should help with increasing the heatsinking mass, therefore, help with dissipating heat.

http://www.taskled.com/h6flex.shtml

$40 driver in a $35 light? Sure, why not. Since when did any of this make sense anyway? ;)

Being a parallel setup, doesn’t it mean that the light is only seeing 4.2V? If that is the case, the linked driver would not work as it requires a minimum voltage of 7V.

It is a massively nicer beam than when I started and the HD2010 should be a good comparison if you know what that beam can look like.
But I should state that beam shots like these can be a bit deceiving. They don’t look quite so flawless in person unfortunately.

In person you will see more shall we say “artefacts” around the center hotspot. This is usually in the form of like a flower petal type halo around the center hotspot, as well as sometimes a faint ring just at the far extent of that flower petal. This stuff is comparatively so much dimmer than the hotspot that the camera with it’s limited dynamic range fails to show it accurately. Our eyes pick it up though.

It all depends on how well focused and centered the emitter is in the reflector as well as the reflector type and quality but if you combine a smooth reflector with a square emitter those artifacts are always going to be there to a greater or lesser extent.

So both these lights exhibit these effects when looking at the beam on a white wall, on the HD2010 with it’s softer hotspot transition it’s only really noticeable when spinning the light and watching the center of the hotspot. On the Bighead the flowerpetal is a little more obvious, I suspect simply as a side-effect of the enhanced definition of the hotspot itself. The ring is also slightly more defined. But this is all with just a quick 5minute focusing so that may still be improvable by further tweaking.

The HD2010 took considerably longer than this to get to the “perfect” focus and alignment…like hours… :stuck_out_tongue: :slight_smile:

Outside you’ll never notice either of these artifacts so ultimately it doesn’t really matter.
I just want to say that if you expect a buttery smooth hotspot when white-wall hunting, you’ll have to settle for less throw and go with an orange peel reflector!

Cheers

I wonder if the 5a ramping lck led driver could be peesuaded to fit?

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?

Yep plenty of space in the driver cavity. You’re going to struggle soldering anything to the aluminium shelf. But you could simply bolt a copper or aluminium slug to the bottom of the emitter shelf/pill and try to size it (or alu/copper foil wrap it) so it’s a press fit into the driver cavity. Then you have some more heatsink mass on the bottom of the emitter shelf and an extra thermal path from there into the walls of the driver cavity/head. Kinda like I did here with my Apex 5T6 here that light had a similar issue with a “floating” driver shelf/pcb.

I’m looking forward to seeing what people come up with to rectify the problems with this light! :slight_smile:

I measured the inside diameter of the stock driver board ground ring at 32mm. That’s the gold ring on the top of the board, the inside diameter of the driver cavity is probably ~34mm/35mm going from that measurement. I’ll get accurate measurements for this when I have the light apart again tomorrow.
So it might just work…

Personally I’m not going to go for multi cell setups on this light, it’s parallel and I like it like that :slight_smile:

1.504"/38.2mm OD, .562"/14.3mm thick. This one also needs more than 4.2v, and also won't run anything but a "3 volt" LED - it's not a buck driver despite the input voltage range.

Of course. Sorry I didn't add all the required health and safety disclaimers! NOTE: SOME ASSEMBLY REQUIRED, TOOLS NOT INCLUDED, WARRANTY VOID IF REMOVED

fair enough. for some reason I thought this one played nice at 4.2v. I’ll go back to sleep :bigsmile:

What’s driving your HD2010? Is it direct drive?

Pretty much, it’s a heavily stacked 7135 driver that will do max 6A. But in reality it only managed 5.8ish on a brand new battery. Generally on a fresh-ish cell it will hit around 5.5A. In that image it was probably doing closer to 5A.
The emitter is an XML U2-1C btw so higher currents are easier than with an XML2, even on Trustfire 26650s.

The HD2010 has somewhat brighter spill and a wider spot so comparing side by side is going to be tricky. But the bighead can definitely project a tighter and arguably brighter spot even in stock form with the tweaked centering ring. Can’t wait to see what it will do when really driven hard!

Hotspot size comparison between the two is fairly close to the difference between a domed and dedomed XML HD2010.

Thanks Linus. I might just go back to XM-Ls for hard driven single cell lights.
I’m waiting to see if you try a resister mod on that driver.

Will give it a shot tomorow.

3x good 18650s even while feeding 6A to the emitter are going to be able to maintain a much higher voltage than even the best 26650 cell I would think. They’ll only be loaded with 2A each and that should be easy going for most good 18650s nowadays. And even Samsung 20Rs have decent capacity if you can use 3! :wink:

This combination should be enough for driving an XM-L2s well to 6A, so I think they are the way to go in this light.
For something like a HD2010 with a single 26650 I agree you might just get better drive current and higher overall performance out of an XML U3 or similar rather than an XML2 U2. Would love to see some tests to back this theory up though! :slight_smile:

But... if XML & XML2 were equal output at equal currents, then sure, whichever one would pull the most current would be the go-to choice, but they're not.