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

It looks like we're getting closer to being on the same page, except for the second part. Let's look back at what I actually said.

I don't see how that could be any clearer.

I am truly interested in those facts though. I've seen many claims of lumens being lost to dedoming, but I haven't seen a formula for it. There's some data here and there, but I haven't seen it tabulated. I'd really like to have a better look at those numbers so I can come up with a decent prediction of how much of the gains would be lost. Is there enough information to estimate a data sheet for a dedomed XP-L? That's academic though. As I said, I don't have plans in the near future to put it under a Carclo, and if someone doesn't try it by then and there's still no XP-L Carclo, then I'll go ahead and take that gamble myself.

Actually, I may have been mistaken when I listed the XP-G2 S3. The S3 is pretty hard to find too. The S2 would have been a better fit in that chart. Anyhow, I don't feel like pulling up the S2 data, so I'll stick with the S3. The XP-L V6 has 26% more lumens at 1.5A than the XP-G2 S3. How many of those 152 lumens would be lost when dedomed? I predicted that the loss would be <152, but >76. Note that I used ">" instead of ">=".

I think the next thing I will be interested is, when kaidomain or fasttech or such gets these in stock. Cutter.com.au is a bit pricey for hobby builds or any series of builds.

1. Cree claims the smaller size means they are cheaper to make than the xml2. I want to see this in action at that checkout.

2. Pretty much a small, but important, improvement on the xml (in efficiency and beam discipline), not xp-g2. (The xpg2 is still what I would want in anything sub 2x18650, like 1x18650 or 4 aa).

3. I got my willbuying xml2 u3 in like 7 days from order to usa. Really would like to see the xpl against this led. I haven’t done anything yet with my u3. I am thinking of building a tripple goose neck (3x hydra neck of about 3ish inches long each, pointed seperately—not too long and bouncy, but long enough), maybe xpg2 in center, mounted to a 4x 18650 pack with ledsupply 700 ma cc dimable controller, and velcro straps for mounting on a paint roller pole &/or bike.

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: