Interesting Dale… Looks like 7.15A is the new highest… do you think that by leaving a small layer of the dome on it increases the throw less than fully de-doming in petrol? Vinh’s lights were tested by rdrfronty to be ~620kcd at only 5.75A. But then again, the difference between 541 and 620 is definitely within the margin of error especially with the inconsistencies with light meters. I know mine reads a little on the high side.
Yup, according to Cree’s datasheet for the XM-L2, it supposedly has an unlimited life span at its rated specs:
We all know that’s not true when we push our LED’s to 3x their rated current, and the previous gen LED’s are rated for 50,000 hours, which translates to 5.70 years.
Hopefully we can find a sweet spot between 5.70 years and insta-poof. 
What I have in my mind is setting up the K50 to a ridiculously high level 7-8A but only use it for bragging rights. Even with my modded K40 or TN31, Level 3 out of 6 is bright enough for me for “normal” uses.
Thanks for chiming in Dale. I’m not sure if a K50 can beat the TK61 when both modded to their max potential (7.0 - 7.5A) because the TK61 has a slightly bigger reflector. I couldn’t make up my mind but I decided on the K50 because if its superior build and stunning fins. Should definitely help with the heat.
You’re one of the people who say that the hot-knife deodming method yields better tints than the gasoline method. Interesting, I’d love to get to the bottom of this.
And I test at 5M, probably not ideal for this kind of thrower. I need to try a 15M test.
That said, I got an Olight SR90 from rdrfronty that I put an XM-L2 in, de-domed, at 6.62A I’m measuring 612Kcd interpolated from the 5M test. My new Courui big head has a beautiful beam profile, doesn’t seem to have convergence but appears to have a tubular hot spot that goes on forever…341.25Kcd. So each reflector is going to have it’s own anomalies.
And he claimed 670Kcd from his. That would indicate he’s gotten more throw from the K50 than the TK61. Not sure if he’s redone the TK61 though, as I understand he’s been working on raising the power output.
rdrfronty’s TK61 is making, they suspect, in the 6.5A range at the emitter.
Oh, by the way, that 7.15A is an emitter amp reading, taken off the negative lead about an inch away from the emitter with a clamp meter while in the light.
I’ve even got a little Eagle Eye X6 doing 6.77A to a de-domed XM-L2 for 1556 OTF lumens. 
Even that little light is doing 82Kcd! :bigsmile:
That’s good news, I almost got the Niwalker Vostro on sale but I’m glad that I got the K50 instead.
I wonder how the driver will handle solder bridged sense resistor pads.
Edit: Hoping that the head isn’t glued…
I think I'll turn mine into a K50M. (scan their product lists, you'll figure it out easy enough)
With an MT-G2?
I wonder what the max voltage of the driver output is.
If it’s higher than the K40/TN31 we’re used to, then the soldier bridging method won’t work and will likely fry XM-L2’s. Precisely calculated SMD resistors (1206 sized?) would be necessary.
If not, it’s going to be almost impossible to drive a MT-G2 with the stock driver.
What’s the typical max current the emitter sees in a standard K50 V2?
There are TK61's out there doing ~8A, at least tested in that realm - just fyi, probably the soon-to-be TK61vn V2.
Also, the 5 meter to 15 meter throw measurements will make a difference for some, maybe most lights, not all though. I measured a TN31 at 435 kcd or so at 5m, then rdrfronty measured the same light at 5m - about dead-on with me, then measured it at 15m and got ~580-585 kcd, so with that light, 15m does help. According to rdrfronty, once you get to 15m, further out distances don't make much of a difference, so he sort of standardized to measure his throw at 15m because of his numerous test trials at various distances.
Not sure what the stock amps is for a K50 V2, but must be up there to produce 1,600 OTF lumens. I'd be guessing at 4-4.5A.
Yes thought it must be close to the 5A mark which is I think is sensible and advantageous for emitter longevity and cell choice.
Modding not out of the question though
I didn’t manage to get in on the group buy, they were gone by the time I saw it. But one of our members has asked me to mod his for him. So I’ll be posting my results here. I really won’t know what I’ll be doing to it until I get into it. Most likely just a de-dome, focus work, heavy wires, lap the star, best thermal grease and resistor mod. I would think that 6 or 7 amps should really be enough for this light. Keep it reasonable so it’s not going to kill it anytime soon. Anything more and you end up in that area where it’s really diminishing returns. I would think this will come really close to the TK61 and should beat my TK61 as it’s not running that high of amps. I’ll be able to post the results of the two up against each other. That should be an interesting match up.
I really wish I had gotten in on this group buy but that’s the way the cookie crumbles and at least I get to mod one.
I’m going to be following this thread closely. It’d be fun to see how high people push their K50s. Of course some emitters will fry at 8A, some might fry at 8.5 or even 9A. It definitely has better cooling fins than the TK61, but also has a slightly smaller reflector.
Sorry to hear that 18sixfifty. It was indeed a very nice deal and the lights did sell out quite fast. Seems like these are limited edition Supbeams indeed.
I can’t wait to get the light. Does anyone know the differences between the K50 and the K50 V2?
Subscribed! Thanks everyone.
So what would be the amp draw per battery for this light in standard form?
I’m assuming 1.5-2.0A per cell, so it’s quite manageable for any cell.
Things get a little different when modded, I’m guessing about 3.0-4.0A as the driver’s efficiency falls.
4.5A output is around 16-17 watts, and with 4 cells in series the current draw is tiny. It should be well under 2A even when the cells are dead empty.
I’m a bit new to modding drivers so I don’t really know much, but why does the driver efficiency fall as you mod it? I’m wouldn’t have thought adding a resistor or bridging connections would cause efficiency to fall so low.
Pushing 12-16A to the driver when the emitter itself will only be getting 7-8A?
With the cells in series, amps is amps. It's just at a higher voltage (more power in watts).
Max voltage is 16.8v, min voltage is 12v. High voltage low current input, to get a low voltage high current output. That's a buck driver.
Driver efficiency falls because more current through the driver means more heat, and heat is wasted electricity. The actual efficiency might not change much, but the amount of wasted electricity goes up.
That’s a good question. I’m not entirely sure, but as you push the inductor, diode, etc. beyond their rated specs, the efficiency of the driver seems to drop noticeably. When I started pushing 6.0-6.5A to my K40 and TN31, I noticed that the driver heats up pretty hot and sucks a lot of current from the cells. If the cells are almost depleted, the driver would try to suck more current for the lack of voltage. This caused my springs to heat up and lose their tension. Copper braiding them helped a lot.
Here’s a video of a voltage sweep with my modded K40. Note how the current draw shoots up to 6.69A when the voltage is about 7.5V.