Results: Testing XM-L, MC-E, SST-50, and XP-G emitters **Updated**

I’ll have to bust out my AW 2900 vs Trustfire Flames graph when I get a chance. They’re pretty evenly matched. Actually, the AW 2600 is better at holding its voltage (resulting in higher amps) than either.

Now...the question is why the difference in amps between the L2P and L2?

EDIT: Yup... I just moved into a new place in Hijacksville. I'm such a hypocrite.

I was just wondering that myself. Gimee 10 minutes.

boredFoy

Sort of like putting an 850 holley double pumper on your honda civic ..

Foy if your flashlight is drawing that many amps instead of thinking of changing drivers to bring your amperage down why not just add two more xml's .??

I just updated my earlier post with the additional readings.

Well Boaz, in an attempt to at least somewhat stay on topic I guess my point is that all these XM-L drop-ins may be needlessly driven too high. Seems like I'm getting 10 or 20 more lumens at the expense of more heat and less run time.

2 more XM-Ls? Yeah, that's what I need; two more XM-Ls.

Foy

Wow Match, thanks for your effort these results are really interesting!

Great job! I really appreciate your work!

Really a great work Match. Would be really useful for everyone that approach a DIY wit an XML.

[quote= Flashlight Foy]

p.s. Match, if this is a thread hi-jack I will quietly delete.

[/quote]

No, not off-topic at all. In fact, this brings up a good point. After testing I took out my MF UF 3 mode drop-in and measured the current it was drawing off the battery ( measured without host. Used ampmeter leads to make negative contact). I measured @4.2a on high with a fresh battery. Then I hooked the same battery directly to an xm-l (DD) and took another reading. Guess what it read? @4.2a!

From what I've observed, with these new "xm-l drivers" is that they are DD in high mode and there is no current regulation happening at all.

I feel any current difference at high end is largely due to the individual cell. With that in mind, I would highly advice against running a low internal resistance cell like an IMR due to the high potential for excessive current. (If anyone has an 18650 IMR and is willing to test this, I'd be very interested to hear the results).

Great work Match , the results are what is expected given the manufacturer's data.

Trooplewis, the loss near or beyond 150 Celsius which is the temperature surely reached for those 'monsters' is around 30% therefore at this numbers a big chunk must be corrected , so I doubt you can get more than 700 L at 5A.

Also, roughly the tailcap current is the emitter current , what the driver burnt is the excess voltage Vin -Vf...

Foy; you are not getting 20 or so more Lumen . Temp corrected probably are getting as say above 700L ...that is what I mean in the other thread , dim , weak, less bright ...

The trick here is find the most you can push an emitter in a given body to get the most. Don't even dream you can put 4A successfully in a flashlight , not enough mass and a lot of thermal resistance.

[quote=oldbobk]

Match,

Thank you for a very scientific test! However, (there's always one of those) what about testing other emitters with the same methodology you used for the XM-L? I'm thinking specifically of the SST-50. As previously noted, 2.8 A. at the emitter is a sweet spot for the XM-L. Where does it start to nose over with the '50? Or the MC-E? People have opined that these two emitters are somehow obsolete, with the coming of the XM-L. I wonder if that is true. I could order some from Digikey (who ship very quickly), and have them shipped to you. You up for it?

Bob K

[/quote]


Since this is a rather recent hobby of mine, I have no experience with the SST-50 or MC-E. Has a test like this been performed yet for either of those two? I haven't looked. The main reason I wanted to do this test was because of all the heresay about the XM-L at >3a (including my own).

Thank you for the offer Bob. I'd be willing to test them though and can return them to you afterwards (pending they don't explode ).

The manufacturers are using the limitations of the battery technology to limit the current to there emitters instead of building high amperage drivers, a very cheap solution to an expensive problem. As battery technology increases I have three direct drive lights now that may burn out. The Ultrafire UF980L, The Manafont Drop-in and the KD C-8.

Excellent effort, Match, and it is much appreciated! I am sure this will be used as a reference for a long while both here at BLF and elsewhere. Keep up the great work. You are truly an asset to the group. 8)

Thanks for doing this test Match! I just got a Trustfire X8 and the most im seeing out of it is 2.56amps at the tail but it is quite bright and throwy with the deep reflector so im really happy with it. im wanting more deep reflectored lights but there does'nt seem to be too many around.

Okay, that non-linear part was bugging me, so I put the data on a regular graph and now I am much happier. This is a great test, Match. Now if I can only find a big block of aluminum with a lanyard . . .

It's not that way .The wattage the resistor must cope is E.I being E the voltage drop across the resistor and I the current.

An XM-L fed with one li-ion at 3A need 1W resistor...Vin 3.7V Vf at 3A =3.35V so 3.7-3.35= 0.35V drop X 3A = 1.05W the resistor being .35/3=0.11666 Ohm

Amazing work, match and foy ;) Looks like 3,4A-3,6A is the best for XML.

BTW, here you have a very good cell comparison: http://lygte-info.dk/info/Batteries18650-2011%20UK.html

The two MF Ultrafire XM-Ls I bought recently (the ones this group suggested) both measured roughly 2.8 at the tailcap using Panasonic 2400s for me. I wonder if you just got a flaky one or if maybe they changed drivers at some point.

What I've noticed is that the amps drawn seems to vary more with the battery I use than between the different XM-L drop-ins I test and remember; we're usually talking about max amps which is often direct drive. My XM-Ls have been fairly consistent and what Match said about DD in high mode is important. Every time I test for amps with these UF drop-ins, medium and low hardly vary at all while high is all over the place. Your Panasonic battery with your XM-L drop-in on medium or low might not be much different because those modes are regulated.

Foy

Great setup and great measurments, Match :)

I compared it to the Cree datasheet specs, and it matches quite well up to 2.5A, then your values are a bit below theirs (3% at 3A). I guess that's due to their measurement method: If I remember correctly, they only power the LED for a small fraction of a second to avoid increasing the junction temperature. (Unfortunately I can't recall where I read that.)

Oldbobk,

"Run in series, you have to have a resistor that will run the wattage of the light"

I understand perfectly what you say but just because the above sentence is incorrect what you get is the opposite. In parallel with the emitter the resistor must be much more powerful than one in series.