Your heat tests looks like confirming janko.hrasko’s thoughts on the heatsinking of the light. Up to 5A and without modification (ie. adding heatsink mass), the default setup works to keep the heat away. That is great news for me because I cannot seem to find a solid copper rod at all here. So, looks like I will have to go with plan B which is to solder in some FT copper heatsinks to the underside of the shelf LED.
Also, with both my lights, they were rattling a bit on the reflector side of things. So, I believe if the shelf LED was to be turned the other way around, again, as suggested by janko.hrasko, then it would put that extra bit of height needed to stop the rattling.
Final thoughts on the light. At stock, it is a thrower and a half. It doesn’t beat my modded Big Head K8 (de-domed Noctigon XM-L2 U2 1A, 2.8A, single cell) for throw and brightness, but it does give it a run for its money. The PWM, as far as my eyes can see, it is high enough for me not to notice.
About modding it. I still have my other soldering iron and some other bits and pieces. I’ll start doing the little things first before getting stuck into the driver. Oh, and all the Noctigons I ordered from Int’l Outdoor recently - all but one of them has been de-domed successfully with petrol. It worked a treat.
Well I wouldn’t use my test to show that the thermal path is anything but adequate. The led didn’t burn up and the light did eventually get hot but that’s about all you can say about it unless you take some output measurements and see if there is any thermal sag affecting output. ~20Watts is a fair chunk of heat to get rid of quickly.
For all we know the emitter shelf could be 40degrees hotter than the body temperature of the light, struggling to transfer the heat into the body fast enough and the led would be even hotter again, losing output as the temperature rises. There’s a big (or maybe small depending on who you ask:P) difference between what might be called adequate heatsinking and a truly effective thermal path. And each bottleneck along the way causes the temperature on the other side to rise above the ideal which is obviously not what we want.
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I will definitely repeat this test once I have a lux meter and then again after I beef up the thermal pathway behind the emitter shelf. I’m very curious if I’ll see any measurable improvement or better stability in the output.
I imagine the key part of the test will be to monitor the output during the regulated 5mins at the start and I’d be very surprised if the stock emitter shelf thread contact isn’t hampering the output in some measurable way.
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Rattling doesn’t sound good that’s for sure, I’d be wary of running the lights for too long before checking into what is loose. Sounds like the reflector isn’t pressing down on the emitter shelf which is them rattling in the threads. Provided the star is glued down that’s not a huge issue but who knows how these lights are assembled half the time. Could be using just thermal paste and then pressure is critical, again I’ve said it before but I’d hate to see one of these reflectors destroyed through a badly heatsinked emitter going smokey! It’s a sad sight and by the time you notice that your reflector is filled with white smoke it’s already too late…
Check the back side of your emitter shelf, wonder if the machining/dremeling marks are only this deep on mine or if they all have it to some extent. I couldn’t flip the shelf as suggested because of this but you may have better luck.
Have you focused up the reflector yet? The improvement from stock was pretty drastic on mine, I’m sure you’ll be in for a pleasant surprise once you have those photons going where they should be!
Recent experiences with testing a couple of XM-L2 U2 1D's leads me to believe it's under-performing for a U2. Want to do true head to head testing to be sure, but I'd say it's output it comparable to a T6 from what I've seen so far. Wonder if anyone else has seen similar results.
If this is true (speculation so far), your big head would do even better with a U2 1A.
I’ve seen this light advertised on various sites as XM-L2 T6 and XM-L2 U2. I guess there’s no way to tell what it really is.
Maybe I should just swap in a XM-L2 U2 1A in my mod just to be sure. Although I’m going to try pushing it at 7A, so maybe I should keep the unknown emitter just in case she blows.
Interesting, I don’t have any way of testing that myself so if you do some detailed testing that would be good.
Mine is definitely quite warm compared to all my other cool whites so I’d expect to see a slightly lower overall output compared to the bluer 1As and greenish 1Cs.
Love the tint though and it’s plenty bright for me, 1As for me are only really an option for dedoming.
Ouchy, Tom is talking about the led I used to replace the stock one. The stock led is most likely a T6 and the one in mine looked like a 1B/1C tint. Replacing it with a known u2 emitter on copper is a must if you’re aiming for 7A.
Yes, I got I think like 3 1D's installed now, and definitely a slight rosy tint in the spill, compared to a 1A or 1C, but I do like it - agree with your impressions of the tint. I bought 10 1D's bare at a good price ($4 each) from Hank a while back, and got lots of bare SinkPAD's and Noctigons.
The rattling does not seem to fully stop when the LED shelf is overturned. So what I have done is used around 4 layers of kapton tape on the underside of the reflector. Add to that, the slightly thicker Noctigon plus the wires, it should stop the rattling. I did a test fit, sans the wire, plus half turned the shelf so that it wasn’t fully tightened, and this did result in the head to stop rattling. I am hoping the half turn would be equivalent to the 18G wire I will be using to wire it up.
Focusing the emitter is something I have not been able to do just yet. However, I will be positioning the LED as far into the reflector as much as possible.
Have you seen my build thread on this light? The underside of the shelf was also badly scratched up. About 30 minutes worth of lapping fixed it right up.
Cool, yeah those scratches were really deep on mine, in the middle the gouges where about a millimeter deep and I didn’t feel like removing that much material from an already very thin shelf. I guess it all depends on how heavy handed the dremeling is on each individual shelf.
I may still lap it smooth when I get round to upgrading the heatsinking since then it won’t matter that the shelf is a little thinner, probably wouldn’t matter now either but hey…
Oh but adding extra layers of kapton tape to the underside of the reflector seems counter productive to me. Since that will hamper how low you can sink the reflector over the emitter for focusing. If you can’t bottom out the shelf even when it’s upside down then I’d say it’s not worth sacrificing your ability to focus the emitter.
The stock centering ring is WAY too tall, so I’d take that down first to the point where when everything is tightened up you have the emitter in perfect focus, then see how much you need to shim the emitter shelf to get some pressure on those threads. Do you have some copper pieces/plate you could use to make shims between the bottom of the emitter shelf and the body?
I coiled some copper wire to act as a spacer but that’s obviously not a good solution, just lets me tighten the shelf threads up.
Hmm, I decide to come back on and the first post I read has this ‘Modder’s Dream’ in it… nice. I guess I need to polish off my international credit card
Anyone measure the throw with a dedomed XML-2 U2 1C in there? That reflector really looks like it should throw, and the beam shots show it as well.
I meanwhile got mine, too, and just did a driver mod like LinusHofmann in #98 (desoldered all components from the board to simply use it as contact board, and get in a NANJG105C 3.0A with custom firmware) and of course used better wires. I'm quite happy with it. My Skilhunt K30GT (firmware modded) blasts it away though :)
Hehe not surprised there!
Out of interest did you also shorten the centering ring to focus up the emitter better? It’s really far off optimal on these when stock.
I’d be really interested in seeing some beamshot comparison photos between these two lights if you get a chance.
Oh that’s interesting maybe the tall centering rings aren’t a problem across the board. If you get the light apart again I’d be interested in a measurement of the emitter centering ring to see if it’s a shorter one. Wouldn’t surprise me to have some variation on these parts.
