XM-L2 upgrade = don't bother (now with pictures)

Flashlight Modding and DIY Parts
21

When looking for maxim brightness from a single cell the difference between XM-L U3 and XM-L2 (even U2) will not be that much, in most circumstances, no more than 10%.
Difference is mostly because of the XM-L U3 BIN. Which is not available for XM-L2.
When looking at all tints below 6000K the advantage of XM-L2 is higher compared to XM-L. More like 20%.

I would say tint can easily change the perception of light output too.
20% increase in brightness is not much to the eyes. 10% is not much at all… So it all depends on the person.

To OP, comparing tailcap readings is a mistake when looking for small differences in output. For all you know, the drivers can have different efficiency. Drivers can easily be between 60-95% efficient. The chance of having 10-20% difference in output when comparing random chinese light with similar tail cap reading is not what I would consider low. They change around on driver circuits all the time, even for similar lights. Also, several of the lights you mention dont excactly come from stores/manufactures that are considered trustworthy (in terms of bin/tint)
Since LCK-LED dont sell XM-L U2 emitters, its a T6 (at best). Which are equevilent to XM-L U3 I dont see how you cold expect to see a difference. The perceived difference you see is most likely a combination of tint and how many amps the emitter are getting (not the driver).
All in all. Your results are not surprising at all.
As for the copper MCPCBs, im pretty sure the ones from LCK-LED are with insulation layer…

Being a flashoholic I will certainly bother upgrading from XM-L to XM-L2. The difference is defiantly there. Is it big? no… (but that is subjective)
I would only care for XM-L2 U2 if looking for CW though, not T6 (or possibly lower bins) that most Chinese lights will use.

22

hmm… maybe if i upgrade all the LEDs on my Tr-J18 mod’ed with KD driver to XM-L2s, would that show much improvement? since they use 3 26650 batteries :wink:

23

+1

24

i also agree with the not killing the messenger, though i don’t agree with the thread’s premise, if done properly i would definitely go for an XM-L2 over XM-L

25

Very interesting thread. Thanks for sharing all this. I like where I live, but it does sound like you have a nice test range there. I just test off my deck at trees. :smiley:

Different tint for different environments is very true. Add to that we all have particular tastes, it makes for a lot of variety. That’s what keeps all this silly stuff fun. :beer:

Would love to see some screenshots, when you can. This all has me feeling a little better about my “outdated” XM-Ls.

26

I’ve have two lights that have had recent XM-L2 upgrades. My kinda weak TN31, with its stock XML U2 got upgraded to XM-L2, on a copper Sinkpad I must add. It went from 1075 at 30 sec. up to 1275 at 30 sec. So even starting with the U2, I had a 200 lumen upgrade. Or about a 19% increase.
Other example is my BTU. It also started with XML U2’s, 3 of course. Swapped in XM-L2 U2’s on copper Sinkpads. Went from 2975 at 30 sec. up to 3670 at 30 sec. So almost 700 lumen increase, again with a nice U2 start. That was over a 23% increase.
Granted the copper Sinkpads and better thermal paste helped in both cases, but still likely I got close to the expected 14% cree estimates for the two bin increase I went. The copper & thermal paste likely gets credit for a good 6-9% on top of that.
So I’m totally pleased with both XM-L2 swaps.

27

I have been extremely busy, but will get to beamshots when I get a chance.

I guess I should make myself an integrating sphere! I assume these lumen ratings come from people who all have them or access to them? I had no idea that so many blfers had made them!

Like I said, I may indeed have a 20% increase in output. My inside wall tests seem to point to perhaps an increased output in that range. But outside in the real world, any output rise is barely noticeable if at all, in my case. Once again, the 10 or so upgrades from stock T6s to U3 emitters all were very noticeable; some were pretty downright mind-blowing. But not with the XM-L2s. In fact, I just put a fasttech U3 in a Trustfire X8 and wow what a diff. Mine excelled at white-wall hunting, but outside in the real world, before the U3, it just didn’t compete well with other similar lights.

I really want to try a u3 or xm-l2 (well maybe not the L2 after this) in a ke-5. I have an extra one ready and waiting, but it’s the first emitter I cannot for the life of me get off the pill Forget Fujik or thermal paste, they musta epoxied the emitter in. I actually bent a formidable screwdriver (and the emitter edge) trying to pry it loose. I might have to use C4.

Thanks to everyone for their input. Hopefully this will be a very valuable thread for anyone thinking of emitter upgrades!

28

I also want to find a way with my camera to lock in the color balance so I can show everyone just how blecchy (pardon the scientific terminology) warm-tinted emitters look out here in an environment that isn’t overly green. I mean we have lots of green. It’s just not predominant: The creosote is coming into bloom as are the yuccas and joshua trees, all of which are BRIGHT green, the creosote with yellow flowers.

But green that is spread out and all of it against a brownish dirt or colorless gray granitic rocks. I tried to do it like a week or so ago, but I couldn’t get it right.

I need the government to extend all days to 28 hours. Then I would have plenty of time for all this fun stuff! :wink:

29

Okay, here are the requested pix. The XM-L2 Small Sun is always on the left. Captions refer to the picture directly below the caption.

Ye olde 2 Small Sun T08 flashlights; as far as I could tell, both had exactly the same output before adding a lck-led xm-l2 to one

Batteries used: Protected samsung 2600s, topped off to 4.20 volts. (Yes, I write down on the shrink tube every charge to keep an eye on how well charges are holding, and with these Samsungs, they hold 4.2 volts exactly for a month or more.)

2 reflectors with xm-l2 installed in the left one.

The moment of truth. Lights are about 6 feet from a PURE white wall. No doubt in my mind which light I will be using. T6 is on the right; xm-l2 is on the left. My eyes say the T6 looks just as bright as the L2, and the pix appear to show the same thing, unless I am reading the pictures wrong.

Another beam comparison outside. Note how browny orangy the warmer L2 is. Warm lights and the desert don’t mix. :frowning:

View from the hill a couple miles from where i live, looking down into Panamint Valley (inside Death valley National Park) with the Funeral mountains to the left, and a smidge of the Panamints to the right. Any light I have dies MILES before it hits the ground from here. Mountains on the other side of the valley are about 12 miles away.

However, I want to go to this spot at night for some serious light testing, and would have by now —- except the 4WD trail to this abandoned mine overlooking Panamint Valley is mucho hairy during the day (with a 1000-foot dropoff on one side), let alone at night. But I have done the road a bunch now and I think I can do it at night. This is about 1/2 mile from my house.

Anyway, there you have it. As you can see, no exaggeration on my verbal description.

I would not recommend a XM-L2 as a mod to this Small Sun, at least the xm-L2s from lck-led.

As you may remember, I also put an XM-L2 in a aurabuy C8 with similar results. I have a couple stock aurabuy C8s on the way and will do some beam shots with that C8 with the XM-L2 and a aurabuy c8 with the stock T6.

The Aurabuy C8 with an XM-L2 shows imilar results to the Small Sun XM-L2 emitter upgrade. The Xm-l2 is definitely brighter than the stock C8, but not brighter than a fasttech U3.

Thanks to everyone for their comments! Hope these pics help explain what i have been talking about.

30

Something changed that shouldn't have during the swap, those hotspots are very different size. If they were the same size I bet the L2 would be noticeably brighter.

Can you swap *just* the reflectors between the two lights, and see if the difference is down to the reflector or the emitter (or something else)?

31

Wow, living that far away from anything you really dont like people, do you? :D

32

Wow. Gorgeous area. Nice clean air and you can see out as far as the eye can see. You have a real reason to have powerful flashlights. I would think you would want light with a high CRI so spot critters like rattlesnakes and scorpions. Do you have scorpions out there?

Not many open areas out my way. Vegetation and trees are quite aggressive here.

Don’t have any input on you beams. The xml2 does seem not as bright. Something must be off. Are your tail current readings on low normal? If they current is high on low, you may have a short.

EDIT: You may want to check for shorts between the emitter pcb and pill even if the low reading are normal. You could have a short that is kept in check by the driver’s current regulation.

33

This picture explains a lot…

1. The XM-L2 hot spot looks way bigger. That always makes perceived brightness go down. If there is no differenecs in reflector, I guess it sits too low (not enough into the reflector) Change around on the reflectors/centering rings. Make both lights have the same beams. Or swap completely around just to see the difference.
2.Your XM-L2 is less cool. Perceived brightness is lower. (Is it CW vs CW btw?)
3. For comparison to be accurate, you should check the the emitter gets similar current. Tailcap reading is not good enough since driver efficiency can be different and invalidate the whole comparison.

34

Wow, what a breathtaking landscape. Must swallow up any light you can throw out there.

As for the Tale of Two SmallSuns, I suspect there’s more at play than meets the eye. Thanks for the beamshots, hopefully we can get to the bottom of this.

35

The T08 with XM-L2/SinkPAD running at 4.2A or 4.5A with a Nanjg driver is my favorite mod of them all so far! Here's the results from the T08 review thread here - https://budgetlightforum.com/t/-/16808#comment-351934:

New #'s on my mod'ed T08. My mod'ed ZY-T08 w/XM-L2 U2 SinkPAD, Nanjg @4.2A lost a 7135 somehow - maybe it never worked day one I'm think'n. Anyway, added another 7135, with the 2 Pana PD batts, measured 4.27A now, and measured output:

lumens - 1,395 @start, 1,366 @30 secs

throw: 100 kcd (broke the 100k barrier)

Not bad with Pana PD's, but probably even better with Samsung 20R's. This is amazing, plus I did another even better at 4.5A, de-domed XM-L2 that got over 200 kcd! I really like the parallel battery setup on this light for mod'ing to XM-L2/SinkPAD's. Just got another T08 in today, probably will do a 4.5A straight XM-L2 U2 1C.

It looks like you have a T6 3C there - comparing a XML T6 1A with a XM-L2 T6 3C, it's apples and oranges... I like the 3C tints, but not when I'm looking for pure power, or comparing brightness to the cool whites because they will dissapoint. In a BLF A8 and an EDC XIAOZHO I got XM-L2 T6 3C's and they are down 150-250 lumens from the T6 1A or XML U3's. Unfortunately, it's hard to find a "true" (no lies) XM-L2 U2 1A, because th U2 1C's are a bit too neutral for many people's taste, I've been finding out the hard way...

36

>>>>>>those hotspots are very different size.

As I said way back in the beginning of the thread, because of differences between the stock star and replacement star, the XM-L2 star is recessed maybe .5mm-.25mm (1/2-1/4mm) lower than the stock star, hence the slightly different sized spots. The solder connections on a 21-mm star need a super thin spacer to prevent shorting against the reflector.

Yes the L2 could be reflowed onto a properly size GIANT star to make the comparisons exacty the same, but I will leave that to others. The spot sizes are less different the farther away they are, i.e., the outside spots are not that different in size. And spots-size doesn’t matter in tailstanding tests.

Tailstanding shows the L2 maybe an almost undetectable hair brighter than the stock T6.

Yes, the test is slightly imperfect, but please don’t forget that I upgraded TWO lights. The XM-L2 in the aurabuy C8 fits exactly the same as the original stock T6. I am waiting for more exact-same aurabuy C8s to compare with the L2 modded C8. BUT, the point is, in the C8 with the L2, I also can see very VERY plainly that the XM-L2 in the C8 is LESS bright than similar C8s with U2s/U3s and not that much brighter than a stock aurabuy C8.

I mentioned that I have two MORE lights intended for this L2-comparison project, two exact-same A0 clones. I have decided not to change one to an xm-l2 but will use a U3 instead. Why? Because I tried both the modded Small sun and modded C8 last night, and the L2 tint is just horrible for this landscape.

And there is NO DOUBT in my mind that the U3 — for me anyway — is the preferred upgrade with noticebly more light, minus the yellowy orange tint of the L2s that I have. So I won’t be doing a third light. Perhaps others will find better-performing L2s from different vendors. But stick a fork in me, I’m done with this project.

ESPECIALLY since last night I noticed that the bottom fell out of whatever brightness the L2 offered when it hit about 3.95 volts. Both L2s became noticeably dimmer. Could this be the more aggressive power demands of the L2 that others have mentioned? I don’t know. Yes, it could be the drivers I am using I suppose, but this sudden dimness did NOT happen with the stock emitters.

This is yet another reason, i will be passing on the L2 for now.

Perhaps with dedicated drivers in lights designed for this new emitter, the promised increased brightness will shine through, but as a drop-in upgrade in existing T6 lights, I am just not seeing ANY benefit to the L2 over the U3 or even a heavily driven T6 in some cases.

I really really wish that others with L2s would post some comparative beam shots. And I hope if others decide to do the L2 upgrade that they will post the results on BLF so we all can get a better handle on what this new emitter offers or doesn’t offer.

Finally, not meaning to sound like a broken record, as one BLFer said in this thread, technical specs are one thing but real-life testing is quite another. I can see NO 20-27% increase in brightness with the L2 over a T6 and certainly NOT over a U3 or even a U2. I WANT to see that increase. I didn’t set out to trash or dis the L2. I wanted a brighter emitter.

I hope others will pick up the testing gauntlet and prove me wrong. Do some more tests; post them here on BLF showing what a super-bright emitter the L2 is.

The second I can see how to make this emitter work, i will be back in line to buy more and use them in the way that does make them brighter. But, until that time, my L2 testing is done. I’m sticking with U3s and heavily driven T6s.

Thanks to everyone for their comments and their help.

37

what do you mean the hard way Tom? :wink:

38

I updated several light already mod'ed to U3 1C and upgraded them to XM-L2 U2 1C's and every time it's a bump and identcial tint, nothing perceived different in the beam pattern...

Not sure I picked it up here, did you post the bin and tint of the XM-L2's you used? This is very confusing....

39

How about a light sent literally half way around the world, only to get it returned because of the tint? Not a monetary loss, and it was handled very well considering, but it was more an emotional stress that maybe I did something wrong here, not explaining it or not asking the right questions on tint. I was thinking the 1C tints would be preferred by most over the 1A or even 0D but I'm wrong about that assumption for sure.

40

That’s really THE key - go with the LED you like for the conditions you are using it.

I tend to prefer a little more cool light where there is no reflective bounce back, like I get from glossy or thick leaves and some tall grasses or water.

I’ve found that when I have two lights like you’re showing, the warmer tint is better for looking at things hiding in foliage, where the cool is better for open, non-reflective terrain. In the desert, it would be no contest for me, either.

Still, even where I prefer the warmer light the cools tend to look like more light to my eyes (and reflections may be helping with that). I prefer it for most outdoor conditions, except when looking in and being under the trees. In the woods, I prefer the warmer LED.

PS - on the reflector focus issue, I’ll have to say in my 2 DSTs the warmer L2 hot spot is very close to the T6 size and if yours starts less focused, then it is probably loosing some throw and lumens OTF so that probably is part of the difference (knowing that you can’t really adjust for it in your setup).