Cree XP-L, XM-L performance in an XP size package

I've seen ~20% in loss of lumens from de-doming with XM-L2's, maybe slightly less, using the gas method. I've heard of lower percentages but I just haven't seen any much lower, maybe 18%, but don't think less than 15%. This is several lights, including Super Shocker triples, but several XM-L2 singles as well, like HD2010's, C8's, etc. Can't guestimate XP-G2's - didn't do enough to see apples to apples. With the de-domed XP-G2's I always seem to lose amps, thinking from a higher Vf - others seen this too.

I bought six of them. Should be interesting to see how they work on the 20mm triple noctigons.

I’d also like to have a better feel for efficiency lost by dedoming. Sounds like a lot of work for somebody though, so I/we may have to make do without.

I was going to reply that I wasn’t so sure about this. I thought I’d looked into this previously and concluded that even a cut XM dome would not fit. Turns out that after reviewing the facts again, it seems clear that comfychair is correct. I don’t know what went wrong the last time I did this, but here’s the deal: The XM-L dome is approximately 4.4mm. I roughly measured this myself just now. The diagonal of an XP- sized package is ~4.737mm. My math isn’t so good these days so I used a calculator to get the diagonal. As you can see, this leaves plenty of room for the little spaces we’ve got in the corners of the XP-L (>0.15mm for each corner). Clearly comfychair is correct about the dome size.

I think they may have sharpened up the area where the dome joins the plain of the rest of the package. Previously there seemed to be sort of a small curved transition, this seems to be gone for the XP-L.

18sixfifty - Are you gonna dedome to fit the optics, or maybe mod the optics? Maybe decide after in hand? I'm goin single for now. Definitely my T10, maybe a zoomie too - might be interesting... Should have ordered more than two.

Since it came up…. have you noticed any change in Vf for those dedomed XM-L / XM-L2?

Lower output is what many of us care about the most. But lower output + higher Vf is an even worse situation. Just getting the same output at a higher Vf means a drop in efficiency… together that’s extra bad. :wink:

Didnt someone successfully even if accidentally dedome as a result of heating the LED via high amps? IIRC, they said the colour did not shift and I was wondering if maybe that might translate to maintaining lumens too?

Maybe the ‘solution’/gasolene is the reason for all/much of the loses and colour shifts rather than dedoming perse?

I’m going to wait and see, but chances are I won’t be able to resist trying to de-dome them. :bigsmile:

I’ll let you know when they show up.

I have 2 of the V6 2D and 2 V6 2A on the way from Craig. Intend to use the 2D as is, try to de-dome the 2A. We’ll see. If the tint is good on the 2D I might put one in the new Nitecore HC90 that’s coming with em. We’ll see how that light fares with it’s stock emitter and what it may take to change it.

I’m not too sure, heating up the emitter with a solder iron or by running it at high amps is still going to give you a tint shift after a dedome.

Well actually heating is how many dedome - not everyone uses gas. XP-G2's I don't believe color shift as much as XM-L2's, so maybe that's why? I dedome using gas and vinh uses heat - I know our de-domed TN31's are very close to the same lumens, and I know his will color tint shift same way. Lot of speculation has gone around, but only known measured lights I've seen #'s on, or seen and measured myself seem to indicate same results.

Calvin*, Craig is my brother :P

My apologies. Thanks for taking the time this afternoon, really appreciate it.

I’m thinking I’ll try some set-ups with the 2D and 2A, get some base output measurements and then maybe try a de-dome with the 2A and see what changes. If it’ll de-dome clean and not tint shift too much, I’ll try a triple in a 14500 sized light. A Buddy wants another chopped mini-mag, these would be a good candidate to ramp it up a bit. :slight_smile: If it acts like an XM-L instead of XP-G then a BLF17DD should allow higher amperage to the triple for bigger outputs, right?

So what do y’all think? Would/should the XP-L in a triple be similar to a triple XM-L? I have a triple XM-L with de-domed emitters, wondering if it should be comparable.

An AW IMR14500 gives over 7A to this triple XM-L set-up through the BLF17DD.

I ordered two XP-L leds, can't even remember which of the tints. When they are in I can do a amp/voltage/output test up to 7A, and when I'm at it I might as well do a dedome (I do that hot) and test it again. And since my vacation money is in (which really is for vacation, but I feel rich now ), I might do a crash test on the other one.

(that leaves me none for flashlight modding )

Just in. Carclo is working on designs for the XP-L. They found out about it when we did.

@Tom E, thanks for sharing your dedome numbers.

@djozz, thanks for taking another one for the team. I can't wait to see the results.

What would the xpl do in a sk 98 ?

Nothing much better than an xml2. The hotspot when zoomed in might look a bit funny.

I’ve got a V5 2A on 16mm Noctigons, one domed and one in the gas. Thinking of using a Convoy C8 and running each through the paces, BLF17DD with a Samsung 20R, find out just what they do.

That’s what we pay you for isn’t it? Oh wait… :wink:

Nice, and I'm jealous, still haven't received them, for a my flashlight hobby it is not advantagous to live in the EU :-(

When the XM-L changed to XM-L2 we saw some differences in the face of the die. Here we go again. There seem to be dots arranged in a spiral pattern on the face of the die. Odd.

The XP-L V5 2A on a 16mm Noctigon in a Convoy C8 with BLF17DD and running an Efest 35A at 4.21V fresh off the charger shows 5.71A for 1252 OTF lumens at start, 1145 OTF at 30 seconds. I haven’t measured Vf, just put one together to see how it looks and acts. The tint here is nice, almost pure white actually. The hot spot anyway, the aura around the hot spot drops in intensity and is warmer. I don’t have any XP-G sized centering rings, so it’s in a standard butterfly centering ring and fiddled with when screwing the bezel down until I got it centered.

The beam profile is perfectly acceptable, I’d be willing to keep this light as is.

I tested the XM-L2 T6 3C on Ryans pill before I put this one in and with the cell at 4.15V it drew 5.93A for 1490 lumens and 1394 at 30. So, even the standard T6 is making more lumens.

I’ll be back to collect my check after I get some more things done, the other emitter should be ready to come out of the gas directly. :wink: