Thanks for the suggestions guys. The MCPCB is copper, and everything looked fine just now when I had it apart. I reflowed the emitter and made sure there was plenty of solder on the middle pad. It sucked itself into place and a light tap on the top of the dome with a q-tip left a couple small balls of solder on the side which were promptly removed. I’m still getting a noticeable blue tint shift at max output with a freshly charged 30Q. On the right is the BLF Q8 and on the left is the M2 (excuse the dirty wall, this is in my garage). I’m not convinced the LED isn’t being over-driven. The light gets too hot to hold in about 30 seconds. I lent my multimeter to my father otherwise I’d see what kind of current is running through it.
I believe that BSOD BEOD (Blue Emitter :-D Of Death) thing is probably the led phosphor layer melting down because of extremely high temperature. It is already known the infrarred emission of leds is quite high, their phosphor layer gets quite hot when operating normally (way hotter than the junction) and my infrared temperature gun confirms this. Check this article: True or false: High-power LEDs don’t generate IR heat in the forward direction like a filament lamp @ EDN Network
Eric587, if you don't mind, could you please reduce the above image's size? To about ¼ is nice enough, I believe.
Thanks.
:-)
Sorry about that I’ve never posted a picture before, it should be fixed now. I think you’re right about it overheating. Oddly enough I can leave it on the 2nd brightest mode (it has blf a6 firmware) which if left on for 5+ minutes get’s ridiculously hot too but there’s no tint shift. The shift only occurs in the highest mode, and it is instant. The other 6 modes the tint matches the Q8 beam you see in the picture.
Or just “100%” or “95%” to fit the screen-width if huge.
And imgur doesn’t let you just rightclick and view-image, but forces you to its own annoying “display page”.
So, I just skip it. <shrug/>
Yep, perfect. 
Well, from what Eric587 reports I can infer the Vf of those SPHWHTL3D50GE4RTMF LH351Cs must be low. This means that Q8 is better served with LH351Ds or the stock emitters.
By the way, how big does the LH351Cs' die size looks to be? 
Curious, it works for me. 
Just to be clear Barkuti, the emitters in both my Q8 and M2 are LH351D’s. I did not purchase any of the LH351C’s.
I have also just removed the bypass wire from the driver spring of the M2, which fixed my blue tint on turbo problem. It actually seems brighter now on turbo, which suggests that it was getting too much current. Still get’s hot very quick which is to be expected.
Maybe I got an odd 351D with very low forward voltage? The 4 in the Q8 handle it’s turbo fine.
Wellp, thanks for pointing it out Eric587. I've been reading bits and tips of this thread here and there, including Bob_McBob's comments, and somehow I got mind messed.
Yes, everything's possible. This is why I love regulated drivers. Look at this regulated MOSFET premiere: 3000mA 3-Mode LED Flashlight Driver Circuit Board @ FastTech
That driver uses an AON7520 MOSFET (50A rating and super low VGS), plus sense resistor to regulate maximum current. :THUMBS-UP:
Lightbringer is gonna have a laugh. 
Cheers ^:)
The M2 is a good host, but upon receiving the first prototype of the Q8 I was very surprised at the extremely good heat handling of it. That may add to why the same leds in a Q8 perform better.
That certainly makes sense, thanks guys :+1:
I installed four of the 5000K LH351Ds (SPHWHTL3DA0GF4RTS6) in a brand new Q8, and the output at turn-on is only 50 lumens lower than stock (5102 vs. 5048). Tint is significantly less green-yellow than the LH351C I previously tried. I much prefer the 4000K LH351D, but that is more personal preference. I will put together a video tonight comparing 4000K and 5000K LH351D to stock XP-L in the Q8 since I happen to have three at the moment.
I put an LH351D in a Wowtac A2S. Lost 40 lumens (1040 -> 1000) and not much change in intensity or beam pattern. Tint looks like a 5000K 219C, but less green. Color, unsurprisingly looks great.
Stock XP-L ~4500K left, LH351D right:
The camera settings are the same, and there’s no significant difference in intensity. The XP-L is overexposing the green channel. I am trying to convince Wowtac they should sell them this way.
Looks really good zak.Wilson, thanks for posting up the comparison pics. :+1:
4000K and 5000K side by side in Q8s.
Bob how does the 4000k LH351D compare with a 4000k 219c? It looks rosier to me judging by your picture.
Should be noticeably rosier at high currents. The Nichia don’t change as much with increasing current.
Oh man, that $0.34 deal would have opened the door to modding my showerhead lights.
Subscribing to this thread for the Maukka tests.