Hi Nightbird, wish you can finish the build with 3 dedomed xpg2 driven hard. I know you probably want to do it on K40. But just now I was thinking about this and came up with a rough estimation of ~700kcd if everything is done right on a BTU shocker.
That is going to be another big leap forward!
I can guarantee you that not everyone is into lux increase at the expense of everything else. Otherwise you would see de-domed emitters and way more XP-G2s and such around here at BLF. In some cases the lumen loss can be quite visible, and in some cases the lux increase is not that impressive. It will depend on emitter/reflector combination.
You are definitely not much into NW or WW emitters.. :p But if de-domed emitters makes "nice warm colors", then you are in for a treat in the future when you try the real deal. ;)
What drive current are you estimating?
Driving 3 XP-G2s real hard is not easy in a BTU.
Hi RaceR86, yes I agree with you on that. Did not realize that before I talked to TomE. He explained to me that driving 3 xpg2 hard is not as easy as driving 3 xml2 because Vf for xpg2 is higher (?) than xml2.
Before one can achieve more throw from xpg2, a nice driver needs to be identified. And maybe an extension tube for shocker can be helpful?
I’m not familiar with XP-G2 specs yet. Also per my tail cap current readings or 3.35 Amps at 12.05 volts, my stock BTU driver should be providing 3.88 Amps to eas XM-L2. I’m not sure is an XP-G2 could handle that.
I’m prioritizing my K40 because per latest LED current readings, it only provides 3.03 Amps to the LED direct wired and 2.43 Amps with 4 R100s added in parallel.
By the way, what’s the maximum current that the XP-G2 can take?
This is exactly the reason why I wont try XP-G2 on my BTU yet. I’ll have to learn everything regarding XP-G2s first. 
I want lux increase but ONLY for my throwers. For my flooders, I’d like to increase the lumens output in some but leave some as it is. My X-10, BC-40 & Terminator will remain stock, all the rest will be modified. :bigsmile:
It turned out after changing my DMM test lead wires that my K40 is getting to 6.25 Amps at the LED, direct wired. I think this might be too much for the XP-G2. :~
Yes lux increase will not be impressive in smaller reflector lights but they will surely throw further.
About tint I have probably one of the warmest tint aspheric available (30KCD that can visually throw to more than 200 meters)
little comparison here:
I want to say that de doming of cool white emitter will be something on half way between these two. It will be warmer than cool white left and not so warm as this guy on the right.
Same KCD value cool white vs warm tint winner is always warm tint. So another case that it is really important what we can see at night and not just KCD numbers.
Luminarium, I have actually used WW XP-G2 in the 7 range, copper mounted, running 3A in aspheric. I also have a de-domed 7C XM-L, lol. Probably ended up with something that would have been a "9" tint.. :D I have de-domed 3C too.. :p
Saying that de-doming a CW emitter makes nice warm tint is far from the truth. You end up in the upper NW range, (if not in the lower CW range) and you often get a yellow-greenish hue with lower CRI than a proper NW. Far from nice warm colors..
I prefer to start with a 1A when de-doming. Does not end up that yellow-greenish.
A cool tint is generally better for spotting things at a range IMO, which is the reason why I do not have any throwers with WW tint anymore..
In multi-emitter lights, the tint of de-domed emitter can certainly be improved though. Improving the color tone of de-domed emitters.
______________________________
Nightbird95.
If you have not checked this thread lately.
I had around 3,5A+ to XM-Ls
Swapped to XP-G2s. close to 3 average.
De-domed two of the XP-G2s, Close to 2,6A average.
Normally, I would not expect up towards 0,4A lower current to each emitter because of de-doming, but with that driver and those de-domed XP-G2s, that was the result in that light.
Generally, its not easy to push several XP-G2s far beyond 3A with typical drivers that are available.
Here is a beamshots comparing XP-G2s vs XM-L2s in a SRK (mouse over changes picture). I have not taken pictures of the de-domed combinations (yet).
As you can see, the XP-G2s does throw a bit furter, but have less output. When that is said. The XP-G2s are then driven fairly close to the max, the XM-L2s are not. And the XM-L2s in my case were only T4. If I had used top bin, and higher current, the XM-Ls2 would have won in terms of throw too.
Same thing should pretty much apply for the BTU too. At similar current the XP-G2s will throw further than the XM-L2s. But since you can push the XM-L2s much harder, then throw is fairly similar. But with the XM-L2s you get much more light output.
The main "advantage" with running XP-G2s is that the light could run a bit cooler (due to lower amps) and still have good throw. You will also get less spill, which can help the visual impression of the beam.
In the BTU, I would stick to the XM-L2s. Its probably better in terms of throw (although, I can not say that 100% for sure).
Thanx for the tips RaceR86!
So the XP-G2 would only appear to throw farther because of its smaller hot spot? If I install XP-G2s to my Shocker (after lowering the current output) then the beam will become more defined and appear to throw farther BUT the spill will become dimmer making the Shocker look like s single emitter thrower with dedomed XM-L. I don’t want my Shocker to perform that way. I’m very happy with its present beam and if ever I mod it again, I’ll be changing the LEDs to XM-L2 U2s or U3s (the present LEDs are XM-L2 T6) and not XP-G2s. :bigsmile:
If you swap your Shocker emitters into XP-G2 of course the sheer lumens output would be much lower.
RaceR86 is right. While this is just being my guess and taking both Vinh’s TN31 (XM-L2 dedomed) and Michael’s TN31mb (XP-G2 dedomed) as reference, Vinh’s TN31 has a little more throw than the TN31mb, and this is with XM-L2 driven at about 6.5A. TN31mb however is driven at stock current with XP-G2.
So in order to make your Shocker to have the throw as much as the XP-G2 you may probably need to drive your XM-L2 emitters at above 6.0A I guess. With 3 emitters and 3 batteries configuration, which mean each 18650 is required to give around 6.0A!
Anyway the above are not scientific assumption though. Need someone to really do the actual mod in order to prove this.
I cant say for sure which will have the furthest throw. Some reflectors does seem to behave a bit differently with different emitters.
Rough guesstimates, you will probably see around 3,2A to XP-G2s and 4,4A to XM-l2s in the shocker with a similar setup. Emitter Vf, and battery setup could be factors the could change the numbers.
I don't think the smaller hotspot with 3x XP-G2s will necessarily make it appear to throw further, if it does not throw further. I mainly think that spill light in general can limit some of the visual perception of throw depending on landscape and weather. When spill hits moist, fog, rain etc it will limit your ability to see far away. The same happens if lots of spill hits the ground in front of you, or a nearby tree or something. Your pupils will react to the light, and limit how good your perceive light. This effect is often larger with XM-L2s. In many circumstanses this does not affect you, and it will not affect lux readings.
I suspect that 3x XP-G2s in the BTU will look somewhat similar to 1X XM-L2 driven to its absolute max in a large single reflector. The XP-G2s should output a bit more light though, if that light is in the center of the hotspot you might get some serious lux numbers. That is, if you can get the XP-G2s far enough into the BTU reflector. The underside of that reflector is flat (based on pictures I have seen).
Yes, the underside of the Shocker’s reflector is flat. I think we need to put a copper strip or something between the LED and the star to raise the XP-G2 a little from its star.
I guess I’ll be sticking to XM-L2 U2s then for upgrade.
Can the XP-G2 handle 3.88 Amps? That’s what I’m measuring with my Shocker.
It can handle more, but due to having higher Vf than XM-l2 when pushed hard, it tend to end up with lower current. Like I showed in post 69.
There are a few people, me included who are playing with XP-G2 around 5A. J)
These tests made by djozz is quite useful and interesting.
Thanx again Torger. :bigsmile:
Your beamshot as an Avatar looks very nice! Well done!
Also, of course, I must say you’re doing very well with your mods. Fun, is it not?
Thanx Dale!
Yes its lots of fun. I usually allot the time 12 midnight and onwards modifying or tweaking my lights. Its actually a way of relieving myself of all the stress at work.
Tint differences could be one of the most subjective areas in flashaholic world.
I said that with de-doming CW emitter you will get warmer color than cool white and that is the fact. I don’t know which color number I got by de-doming but is this really important? It really looks much warmer than CW I know that there are warmer colors than that but my vote goes to color of de-domed CoolWhite emitter.
Color given by de-doming Cool white emitter will be much nicer than stock cool white color. In reflector lights there will be no greenish tint. As you said it could be little greenish tint with aspheric but I would say it is hardly noticeable because you are not building this lights for white walling and watching tint 5 meters from the wall but for field use from 50 to 800 meters with riflescope and I guarantee that you will perceive things better with de-domed cool white than with domed cool white.
Saying that cool white is better for distant spotting things at the range? It could be true but mostly it is not true.
CW has advantages:
Cool white will be better for distant spotting of high reflective targets(especially white color targets), It will reflect better from bigger surfaces(buildings) and that is it.
And disadvantages:
But in real field use (grass, trees, game) cool white will not look as natural on them because of very high reflection from the target. Green grass or distant tree will look blueish to human eyes. Brown game will look grey. It reflects on unnatural way.
I would say that color between CW and WW works the best, de-domed CW is somewhere between them…
It does not have high reflection from the surface and it will give more accurate color rendition and we perceive things as they are. Warmer colors are more “eye friendly”.