on my mods i do not use a centering ring or paper washer like the uf-t20’s come with. try removing them then take a black sharpie or black paint pen and black out the brass pill, the solder blobs, even the shiny letters “cree” on the mcpcb star can reflect crap into the beam. black out anything shiny that can reflect “crud” into the beam. i actually think this will help your light quite a bit. let us know how it works.
I actually can read Cree xml under the hotspot when i point it at my white ceiling. But I’m not annoyed by the small reflections that are visible now, the flowery debris were much more visible.
But since light is reflected back around the led, will i lose lots of lumens now when i don’t have the white cover left?
Technically no, as black absorbs all light, white reflects all light.
Chris
I have tested the uft20 with and without the ring and washer. There was no measurable difference in output.
yeah, definitely no measurable difference
and for me, with an aspheric thrower, artifacts and any sort of spill are highly undesirable
I use vht flameproof flat black (exhaust paint) on stuff that gets hot (pcb, pill) and black plastidip (which is pretty flat if you apply it in lights coats) on everything else.
Wow Kevin, that is very humbling to hear you say something about my work like that. I'm so glad your pleased. Thank you again.
Yep, 20mm star, 17mm driver. I will keep the thread open for a while, I cant promise it will stay open indefinitely, but there seems to be a good bit of interest.
you’ll probably get a second round of requests once we start posting beamshots and lux measurements.
I might have to get out the temp probe for my multimeter, too
I’m quite sure the biggest reason to use one of these is for high power stuff like kevin is doing, but I’m wondering how much lower the PCB temp will be after a long run at something like 3A.
I expect that even when the light body has reached a steady state temperature, the PCB will still be significantly cooler than with the stock brass pill. It should be an easy test to do, since I have 4 UFT20s, and two already have a sinkpads soldered to them :bigsmile:
I do not want to spoil the game, and I certainly find Matt's work amazing in all aspects! , but without being a thermodynamics expert my judgement is that there will not be a huge difference changing a brass pill to a copper one. Sure with the high amp mods it will do something (and here at BLF every lumen counts 
), but my feeling is that it will not make a world of a difference. I do not have the skills to calculate it through (sorry), but I think the biggest gain was obtained with the copper sinkpad with direct metal-to-metal bonding of that tiny thermal pad on the led all the heat has to go through straight to the copper core of the board. And the real improvement of using copper for the led-board is not so much the high thermal conductivity (which I admit does not work against heat sinking ), but simply that it is solderable and aluminium is not. The pill is further away from the heat source and the surface area the heat goes through there is so much enlarged already that this further-down-the-road heatsinking will go smooth whatever (good conductive) metal the pill is made of: brass, aluminium or pure copper.
But I really, really want to be proven wrong here, because it would be awesome if even more light is being produced with these copper pills
stock pill in the uft20 is solderable (brass)
there will be much more pcb to pill contact area w/ these copper pills (center of the stock pill is raised and contact is <16mm diameter).
but I’m not sure what the gains will be either, which is why I plan to test it 
you do make some valid points. once the entire pill and body are heatsoaked it really won’t matter what material they are made of, without some form of active cooling. but what what the copper pill will do, is buy you some time before the led junction temperature starts dropping the the light output.
based on my own testing going from aluminum star to copper sinkpad, and on my very very basic understanding of the differences in thermal properties of brass and copper.my geuss is we will see approximately a ten percent gain(maybe more) in light output just switching to copper pill, with everything else being the same: driver, emitter and mcpcb. just a geuss.
i hope to see some actual temperature data from someones testing.
i’ll bet one of the BLF thermo engineers will be able to add a more scientific explanation.
really? edit: (meaning, i’ll be suprised if there’s a gain at turn on w/ copper pill)
i thought w/ <3A we wouldn’t see much difference between copper on brass pill and vs copper on copper pill in the first say…minute of run time
we shall see once I receive my pills.
It won’t be 100% scientific, since I don’t have a power supply, but I’m thinking of just taking a video of two lights and two temp meters at the same time with the same setup
xml2, nanjg 105c at 2.8A, multimeter w/ temp probe on pcb (no head on the light body)
I have two multimeters w/ temperature capability, so once the video is done, I can play it back and put the measurements in a spreadsheet for graphing
As others have stated, the most important junctions are the ones closest to the heat source, so the copper star (SinkPAD) is probably the biggest difference. I thought someone else (I tend to agree) that the junction between the star and pill is important, but not much difference between a good thermal grease and solder, since the thermal characteristics of solder isn't that good anyway. So for now, I'm thinking of staying with Arctic grease there as long as it's makes sense (good bond from reflector or polished surfaces that bind well) - making it more flexible.
I'm thinking the copper pill vs. brass or aluminum will have an effect, but may be minimal or just delay the heat conductivity process further. For a lot of my builds, the first 1-3 (6 at most) minutes are critical (and most asked for) - I'm not too concerned about longer than that, unless a specific usage is in mind for prolonged "high" use. There is always medium and low modes and I could beef up the custom programmed medium mode to 50% (or more) if that works out better.
I've only seen hollow pill C8's with Q5's, not XML's, but maybe the XML C8's I've worked were pricier, in the $15-$20 range. I would think it will all depend - sure it will make a bigger (maybe big) difference if only replacing a hollow pill with this copper pill, leaving a stock alum star, but the beefed up C8's I have already are converted to XM-L2's on a SinkPAD on brass pills, no hollow pills. I think the $20 is better spent on a XM-L2/SinkPAD, or U3/SinkPAD first, but I definitely want to try these copper pills, first to see if straight upgrade will improve brightness and thermal conductivity, but also then maybe up the amps even further.
Very nicely done VoB.
What are the dimensions of the pill?
HI all,
MY ultrafire C8 came today. These pills DO in fact fit mine perfectly. With the pill threaded all the way down the lens was slightly loose, so a thin O ring under the pill or a change of the lens O ring MAY be needed to compensate for the variance in individual lights.
Hopback,
The dimensions of the pill are:
.556" tall
.998" largest diameter ( top rim where the PCB sits)
.894" Outer thread diameter.
There may be about a .005 variable on any of those for the actual pill received.
Whats the difference in height between the face which the driver seats on in the host, and the height of pill where the star sits?
The higher the better, if its +1mm I can get an xre (de domed) to focus with an xpg reflector, at over 70k lux with 1.4 amps. Just imagine what it will get at 2 amps plus
Chris
Hi VOB - any updates on this? Thanx!
crnkrn,
I will get back to you with that measurement when the batch is done.
EDIT the distance from the from the base of the pill to the place where the MCPCB sits is .480 From the lip where the top face of the driver sits to the MCPCB rest is about .405
Tom E,
The metal has arrived, I have a good start on the batch. I suspect they will be ready for shipment by Thursday.
I finally got the 5a driver in from FT and started test fitting the parts. Hopefully will get it completed and running wednesday. It seems like its going to be a tight fit for the double board driver. Hopefully I have a battery that will get close to 4-5a. The pill has been sitting on the work table and I just randomly stop and stare at it. :bigsmile: