Emitter Test Results pt4: XML2, XP-E2, XP-G2, and Nichia219! (along with sinkpad tests)

[moderator007]

@Pulsar

Thanks match, been waiting for a test on these.
Would the higher vf on these be accounting for the 2.25a draw using a 3.5a driver? Or is there something else coming in to play here?

Thanks again, your tests are invaluable to us here

Are you using a single cell driver?
And if so, what battery are using?
Update: Pulsar I found your thread with the mag, I’ll take the discussion there.

[apt323]

Great information as usual, thanks!

[Slim_Pickens]

Sweet mother of pearl. As always—a big “thank you” for the data, match! I’m looking forward to how the XP-E2 fares. Will it have a higher Vf than its predecessor, like the XM-L sequel? Or will it be notably lower like XP-G2 vs. G1?

@scaru

Great work Match, so now it looks like the vf of the XM-L2 is very similar to that of the Nichia 219.

I know. It looks like high currents will call for 4xNiMH in a Mag. All the better for heatsinking, at least.
On the upside, the XM-L2 hovers around 62 lumens/watt at nearly thirty watts, >1.5A/mm^2, and delivers >400 lumens/mm^2. That’s crazy!

[relic38]

Excellent work Match! This puts my ‘XM-L2 on copper SinkPads BTU Shocker’ mod very high on my list

[PilotPTK]

Pretty Awesome that you can see the increase in Vf (roughly 0.15V at 3.0A) with the emitter on the Copper vs the emitter on the Aluminum. This is almost certainly attributed to the lower operating temperature of the emitter on the copper. Some of the difference, however, is likely just emitter to emitter variation. I’d love to see what the difference in the Vf to Current curve would look like for the same emitter soldered to an Al vs. Cu star.

You should, in fact, be able to work backward and figure out what the actual die temperature difference is between Al and Cu. It’s easy to calculate - 1.6mV difference per degree C.

PPtk

[Slim_Pickens]

@PilotPTK

Pretty Awesome that you can see the increase in Vf (roughly 0.15V at 3.0A) with the emitter on the Copper vs the emitter on the Aluminum. This is almost certainly attributed to the lower operating temperature of the emitter on the copper. Some of the difference, however, is likely just emitter to emitter variation. I’d love to see what the difference in the Vf to Current curve would look like for the same emitter soldered to an Al vs. Cu star.

PPtk

+1
I agree; Sinkpad’s design is definitely doing it’s job! I’m impressed.

[RaceR86]

Thanks for sharing…

This is how I would rate the upgrade by looking at your graph.
Up to 1,5amp, no difference
1,5-2,5 minimal difference
2,5-3,0 some difference, about 10% at 3A - or 100 lumen gained compared to aluminium.
3,0-4,0 defiantly some gains. Especially when getting close to 4A. About 200 lumen gained compared to aluminium star @4A. Or 15% increase.
4-6, huge gains

1500+ lumens @ 5A. NICE!

But, gains are mostly when having high vf.
Can someone explain to me how real life gains would be when using a 4-5 amp driver and only 1 li-ion like a Panasonic NCR18650B Protected in combination with a linear driver… Would there actually be any gains at all?

Using one protected 18650 in combination with a boost driver, would there be any issues?

If using only one battery, I am assuming larger , low resistance, no protection would be helpful. But pushing 5A for some time would not be realistic even with one “high ouput” 26650, or??

[rdrfronty]

@relic38

Excellent work Match! This puts my ‘XM-L2 on copper SinkPads BTU Shocker’ mod very high on my list

Exactly my plans. Got all my parts ordered. Just have to wait for these dang XM-l2’s to eventually come in.
And thanks match for the awesome tests!

[PilotPTK]

@RaceR86

But, gains are mostly when having high vf.
Can someone explain to me how real life gains would be when using a 4-5 amp driver and only 1 li-ion like a Panasonic NCR18650B Protected in combination with a linear driver… Would there actually be any gains at all?

Even the best 18650’s aren’t going to push the XM-L2 harder than about 3.6 to 3.8 Amps on a linear or switching buck driver.

[moderator007]

@PilotPTK

@RaceR86

But, gains are mostly when having high vf.
Can someone explain to me how real life gains would be when using a 4-5 amp driver and only 1 li-ion like a Panasonic NCR18650B Protected in combination with a linear driver… Would there actually be any gains at all?

Even the best 18650’s aren’t going to push the XM-L2 harder than about 3.6 to 3.8 Amps on a linear or switching buck driver.

And even if it does make that suggested current it would not stay there very long maybe a couple of minutes at best. A IMR cell would probably stand the best chance at it. Possibly 8 to 10 min judging by HKJ’s IMR graph.

[PilotPTK]

Yep, the XM-L2 really wants two LiIon cells and a buck driver. That would be ideal.

PPtk

[RaceR86]

@moderator007

@PilotPTK

Even the best 18650’s aren’t going to push the XM-L2 harder than about 3.6 to 3.8 Amps on a linear or switching buck driver.

And even it does make that suggested current it would not stay there very long maybe a couple of minutes at best. A IMR cell would probably stand the best chance at it. Possibly 8 to 10 min judging by HKJ’s IMR graph.

I had a feeling that would be the case…

[AlexGT]

Thank you for the analysis Match, What bin were the XM-L2? Tint? Where did you purchase them?

Thanks!

[nofearek9]

thanks for the test,sinkpads do great job.

[bibihang]

Thanks Match. Now I just need to know where can I get those XM-L2 on sinkpad

[ergotelis]

excellent work Match, thanks!
Particularly this Vf graph is neccesary for a good mod! I was expecting the lumen results but i was a bit surprised from the Vf graph. Do you have any xm-l for comparison? THanks!

[bdiddle]

What bin is that XM-L2?

[georgek]

very nice work… thank you very much…!!!

I also need to know where to get xm-l2…

[NightCrawl]

@texaspyro

Yes, but isn’t Match is sinking copper to big chunk 'o copper? Results would be less spectacular if the copper sinkpad was sinking to a chunk 'o aluminium like in most flashlight bodies.

Yes he is. But the difference is not that big, see here:

Taken from here: http://www.taschenlampen-forum.de/modding/13515-bastis-bastelbude-13.htm...

Testing of a copper star on Alu, Cu and Ms (brass) heatsinks.

Thank you for the test Match. Nichia 219 in sight? :D

[ImA4Wheelr]

Great info. Thank you Match!

So it appears that even running multiple healthy parallel cells wouldn’t run very long at 5A. Guess one needs to consider getting the equipment needed to measure capacity and rate of discharge if they want to push an XML2 hard.