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

Thanks Match,I love these "where the rubber hits the road" tests.The sinkpad really makes a difference and is clearly the winner over the aluminum mcpcb.It seems XML-2 is best suited in a multiple cell configuration because of the higher vf.Very valuable info for modders,and out of curiosity what is the bin of XML-2 in this test?

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.

Thanks for the valuable information Match.
I guess amc7135 drivers are out at high currents. The battery wouldn’t be able to stay above vf of the led and the .12v overhead for the amc7135’s, at least not for very long anyways.

Great work and Thank You Match

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

Thanks for the testing match. Interesting results.

Pulsar wrote:

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

Great information as usual, thanks!

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 wrote:

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

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

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

PilotPTK wrote:

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

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??

relic38 wrote:

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

RaceR86 wrote:

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?

PilotPTK wrote:

RaceR86 wrote:

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.

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

PPtk

moderator007 wrote:

PilotPTK wrote:

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..

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

Thanks!

thanks for the test,sinkpads do great job.

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

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!

What bin is that XM-L2?

very nice work.. thank you very much..!!!

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

texaspyro wrote:

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?

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.

texaspyro wrote:

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.

Thanks for doing the measurements.

WOW!

Thanks for doing those tests.

Thanks Match!! This confirms what I've been seeing in the few XM-L2/SinkPAD builds I did and posted about. I ordered a Small Sun ZY-T08 exactly because of the 2 parallel battery configuration - perfect for a hot XM-L2/SinkPAD/Nanjg 3.85A or 4.2A setup.

 Also, these results don't mean you won't see much of an advantage from single cell applications - even at lower measured amps, results are impressive over XML U3's on aluminum. I've also seen outstanding results with an XML U3 on a SinkPAD and having the same high Vf issue with that, so it's not so much an advantage of the XM-L2, it's the SinkPAD's advantage. For single cell applications, switching to lower resistance batteries directly results in higher amps, higher measured lumens/throw - I've done this on a few lights by testing with an AW IMR 2000 mah.

 So, I'm seeing greater gains with a SinkPAD upgrade than upgrading to an XM-L2 emitter only, so, Match's results seem to confirm this. I'm not saying XM-L2's have no merit - they do with efficiency, and with equal bin, equal tint, they should do better than an XML, but unfortunately the best/brightest available XML emitter is a U3 1A/1B/1C, while the best/brightest XM-L2 is U2 1A/1C now, and I've only used XM-L2 U2 1C's and XM-L2 T6 3C's up til now.