Lumileds Luxeon V, test of a 4000K 70CRI emitter

207 posts / 0 new
Last post
Flashy Mike
Flashy Mike's picture
Offline
Last seen: 3 days 1 hour ago
Joined: 01/14/2016 - 16:38
Posts: 1166
Location: Germany

Where do I lose voltage? 3 cells in series sum up to about 3.3V at 5 amps, where the LED is pretty efficient. Eneloops should be good for this current, HKJ tested them up to 10 amps with a max. temperature raise of about 20 °C. Even the capacity of the cell doesn’t decrease much at higher currents.

djozz
djozz's picture
Offline
Last seen: 2 hours 42 min ago
Joined: 09/07/2012 - 17:04
Posts: 14962
Location: Amsterdam

Coincidentally I was able to do a quick check on 3 Eneloops in series because a few years ago I made a 3xAA carrier with phosfor-bronze springs and Omten switch (using Oshpark boards) for a project that I never finished. Pushed against the Luxeon V-modded VG-10 head I checked the output on 3 fully charged Eneloops, 30 seconds after switch-on I measured 1400 OTF lumen, that is about 1600 led-lumen, which should be about 4.2 amps (measuring the amps directly is not as quick as this was).

Of course upon draining the batteries the output goes down considerably (though not dramatically because the voltage curve of the Luxeon V is relatively steep), but this at least shows that a 3xNiMh set-up should work well enough to make a flashlight with very decent output.

Flashy Mike
Flashy Mike's picture
Offline
Last seen: 3 days 1 hour ago
Joined: 01/14/2016 - 16:38
Posts: 1166
Location: Germany

Thanks, djozz, that’s close to what I expected. Looking forward to my X3 mod once the LEDs arrive …

djozz
djozz's picture
Offline
Last seen: 2 hours 42 min ago
Joined: 09/07/2012 - 17:04
Posts: 14962
Location: Amsterdam

Today I tried the Luxeon V 4000K 70CRI in my black Emisar D4 (see the WDYMT thread). The output and beam were very rewarding, but although it still looks alright, the tint is better in the VG10. I can’t say for sure but I expect it is a reflector vs TIR thing, the hotspot from the TIR is more yellow, and the rosy appearance in the VG10 beam is not obvious in the TIR beam.

Also, while playing with both flashlights, it looks like the tint is better (more red in the tint) at high current when the led runs on the FET than at low current when the led runs on the 7135.

Agro
Online
Last seen: 3 min 3 sec ago
Joined: 05/14/2017 - 11:16
Posts: 3983
Location: Ślōnsk

So they fit under Carclo optics without dedome. Smile
It makes it somewhat more likely we’ll see the triple / quad MCPCBs for them eventually.

djozz
djozz's picture
Offline
Last seen: 2 hours 42 min ago
Joined: 09/07/2012 - 17:04
Posts: 14962
Location: Amsterdam

The black D4 with LuxeonV’s runs pretty efficient even on highest setting. On a freshly charged 30Q I measured 15A for the first minute. A 30Q at 15A has a voltage of about 3.7V in that minute, so the power use is 55.5W. If you take the output at 12 seconds, 4620lm, the flashlight efficiency is 85 lm/W, which is rather good. This is not surprising because it is a quad, each led receives just 3.75A in which region the LuxeonV is still quite efficient (guess what, it is even well within specs Party ).

The same story goes for XP-L(2)’s btw, and even in somewhat less extend for XP-G2 and 219C.

This implies for me that a triple channel driver in a multi-emitter light like the D4, or the FW3A, is a nice luxury and should certainly be aimed for, but the huge efficiency boost in the middle modes that some folks promise does not quite happen, it will not be more than an unnoticable 10 or so percent.

Lights that have a complete battery available per led (single led single li-ion, or i.e. the Q8) drive the led on highest setting very close to the inefficient max, in that case a triple channel will have some merit.

Agro
Online
Last seen: 3 min 3 sec ago
Joined: 05/14/2017 - 11:16
Posts: 3983
Location: Ślōnsk

I remember someone measuring D4 (not sure which emitter) runtime @350 mA and arrived at under 100 lm/W. Actually I think it was eighty something.

djozz
djozz's picture
Offline
Last seen: 2 hours 42 min ago
Joined: 09/07/2012 - 17:04
Posts: 14962
Location: Amsterdam

Agro wrote:
I remember someone measuring D4 (not sure which emitter) runtime @350 mA and arrived at under 100 lm/W. Actually I think it was eighty something.

I checked the black D4 at 1×7135: I measured 347mA with an output of 149.6 djozz-lumen. The 30Q was at 4.09V resting voltage and loosely interpreting HKJ’s graph I see at that drainage stage and 350mA a battery voltage under load of 4.07V. The power is thus 4.07×0.347=1.41W. That calculates at 106 lumen/W.

That is with the 7135 burning off 1.3V overhead voltage (.45 W). Would a buck driver exist that converts that 100 efficient in output then the efficiency would go up to 156lm/W. Dreams!

(as a side note: my djozz-lumen, which in some comparisons that I did looks like it is ~9% optimistic compared to real lumens still appears less optimistic than the lumen that most people’s on BLF and most well-known flashlight manufacturers use)

Flashy Mike
Flashy Mike's picture
Offline
Last seen: 3 days 1 hour ago
Joined: 01/14/2016 - 16:38
Posts: 1166
Location: Germany

djozz wrote:
Also, while playing with both flashlights, it looks like the tint is better (more red in the tint) at high current when the led runs on the FET than at low current when the led runs on the 7135.
Is the tint also better when FET is running with lower duty cycle (e.g. with 1 Ampere) – or only when FET is near 100%?
djozz
djozz's picture
Offline
Last seen: 2 hours 42 min ago
Joined: 09/07/2012 - 17:04
Posts: 14962
Location: Amsterdam

Flashy Mike wrote:
djozz wrote:
Also, while playing with both flashlights, it looks like the tint is better (more red in the tint) at high current when the led runs on the FET than at low current when the led runs on the 7135.
Is the tint also better when FET is running with lower duty cycle (e.g. with 1 Ampere) – or only when FET is near 100%?

Very difficult to see because the tint change that I think that I see goes together with a large brightness change and a brightness change alone already makes your eyes perceive a different tint. So yes, I think it is already better with FET at low duty cycle but the effect is not at all obvious.
Flashy Mike
Flashy Mike's picture
Offline
Last seen: 3 days 1 hour ago
Joined: 01/14/2016 - 16:38
Posts: 1166
Location: Germany

If it depends on high current it might be another point against triple channel drivers. After using several lights with Nichia 219C 4000K CRI92 I’m pretty spoilt with tints.

djozz
djozz's picture
Offline
Last seen: 2 hours 42 min ago
Joined: 09/07/2012 - 17:04
Posts: 14962
Location: Amsterdam

I crunched the numbers, here’s what I measured, LuxeonV on a XP-Noctigon compared to LuxeonV on led4powers 4040 board. They were different leds so some difference could be expected regardless on which board they were. But the performance on the lower currents is so identical that I’m inclined to attribute the slight difference at high currents to the boards and not to the difference between the leds. I checked the quality of the reflow after the test by desoldering the led and checking the solder pads for incomplete reflow, everything looked fine.

My conclusion: the 4040-board has the slight edge, but only at very high current. But apart from performance, the 4040 board makes reflows way way easier and robust.

I wanted to be gentle to the led to be able to use it afterwards, so I stopped the test at 11A, but looking at the chart it looks like the output decrease when the current is over the maximum-output current is clearly lower on the 4040 board. This suggests a healthier led in case of abuse when a 4040 board is used.

Flashy Mike
Flashy Mike's picture
Offline
Last seen: 3 days 1 hour ago
Joined: 01/14/2016 - 16:38
Posts: 1166
Location: Germany

Thanks for the numbers!
Would like to see this LEDs in my D4 …

Enderman
Enderman's picture
Offline
Last seen: 1 hour 55 min ago
Joined: 11/03/2016 - 22:42
Posts: 3926
Location: Vancouver, Canada

Hey I just noticed this, but “a thermal resistance of 0.8 degC/W, which is 3 times as low as any existing high power led” is not really correct, the CFT-90 has a thermal resistance of .45C/W at the junction.
But this is probably because the LED chip itself is like 10mmx10mm or something huge like that Silly

The_Driver
The_Driver's picture
Offline
Last seen: 4 hours 56 min ago
Joined: 10/20/2016 - 05:51
Posts: 1349
Location: Germany
Enderman wrote:
Hey I just noticed this, but “a thermal resistance of 0.8 degC/W, which is 3 times as low as any existing high power led” is not really correct, the CFT-90 has a thermal resistance of .45C/W at the junction. But this is probably because the LED chip itself is like 10mmx10mm or something huge like that Silly

Yes and no. Big Smile

0.8°C/W is by far the best value ever for a 4mm^2 LED (XM-L2, XP-L2 etc. => usually around 2.5°C/W).
Luminus has traditionally reached the lowest thermal resistances because they use larger DIEs and a special direct-to-copper mounting technique (notice that they have two sets of bond wires, the current doesn’t got out the bottom of the DIE).

Generally LEDs with large DIEs seem to have lower thermal resistances. I think it makes sense to compare thermal resistances relative to the Die size, so I multiply them (so lower values are still better):
XHP70.2: 0.9°C/W * 14.2mm^2 = 12.78
CFT-90: 0.45°C/W * 9mm^2 = 4.05
XHP50.2: 1.2°C/W * 8.24mm^2 = 9.89
XHP-35 HI: 1.8°C/W * 5.9mm^2 = 10.62
Luxeon V: 0.9°C/W * 4mm^2 = 3.2 (I had to guess here regarding the DIE size)
SST-40: 2.5°C/W * 3.994mm^2 = 9.99
XP-L2: 2.2°C/W * 3.55mm^2 = 7.81
XP-G3: 3°C/W * 2.06mm^2 = 6.18
Osram Black Flat Gen2: 4.3°C/W * 1,122mm^2 = 4.82

So it seems the Luxeon V and the CFT-90 are indeed very good, but the Osram Black Flat, XP-G3 and XP-L2 certainly hold their own.

I’m not sure theses theoretical values tell the whole story though or even have any meaning at all. I am completely ignoring the size of the LED package and thus of the center solder pad. The Luxeon V has a larger solder pad compared to the XP-L2 and the SST-40 is even larger than the Luxeon.

djozz
djozz's picture
Offline
Last seen: 2 hours 42 min ago
Joined: 09/07/2012 - 17:04
Posts: 14962
Location: Amsterdam

djozz wrote:
Today I tried the Luxeon V 4000K 70CRI in my black Emisar D4 (see the WDYMT thread). The output and beam were very rewarding, but although it still looks alright, the tint is better in the VG10. I can’t say for sure but I expect it is a reflector vs TIR thing, the hotspot from the TIR is more yellow, and the rosy appearance in the VG10 beam is not obvious in the TIR beam.

Also, while playing with both flashlights, it looks like the tint is better (more red in the tint) at high current when the led runs on the FET than at low current when the led runs on the 7135.


I’m using the D4 with Luxeon V’s everyday now during a short holiday on Schiermonnikoog. Despite the very small margins between the solder pads on the ledboard because of the non-fitting footprint the light holds up fine and proves to have a very good and pleasant tint for use in a natural environment. Actually in showing contrast and depth it does no worse than my E2L with 4000K R9080 219B’s.

But I still feel a bit lonely using this led, is there anyone else who has used the Luxeon V in a flashlight? Experiences?

led4power
led4power's picture
Offline
Last seen: 4 hours 49 min ago
Joined: 12/29/2012 - 09:48
Posts: 1119
Location: Croatia,EU

I built S2+ with 9A LD-A4 (+ thermal enhancement kit) and Luxeon V on 16mm DTP, it works nicely,I'm seeing highest lumens from 4mm^2 die LED with absolutely great tint, it's pretty unbelievable this LED is only 70CRI,it has quite a bit of red in spectrum and beam is very uniform across emitting angle, also tint is very consistent over wide range of current. CREE XP-L V6 3D tint looks pretty crappy compared to Luxeon V, and it has less output too (fast drop due to high Vf).

The Miller
The Miller's picture
Offline
Last seen: 1 year 1 month ago
Joined: 12/14/2015 - 12:08
Posts: 9630
Location: Charente France

Djozz, the same depth and contrast as 319b sounds great
Do you think it is a candidate for the FW3A?

ImA4Wheelr
Offline
Last seen: 4 days 8 hours ago
Joined: 02/03/2013 - 14:51
Posts: 7882
Location: SC

djozz wrote:

. .  But I still feel a bit lonely using this led, is there anyone else who has used the Luxeon V in a flashlight? Experiences?

 

Been trying to join you, but the footprint is frustrating me in my chosen target, the Q8.  It looks doable.  Sorry for the off angle of the picture.  Seven reflow attempts so far.  All seemed dead on.  The last few reflows were just one emitter, the other 3 excluded.  Always shorting the positive side.  Even if I hold the emitter from where it wants to sit.

If I want to keep the stock mcpcb, I think I will have to modify the pads slightly.

 

djozz
djozz's picture
Offline
Last seen: 2 hours 42 min ago
Joined: 09/07/2012 - 17:04
Posts: 14962
Location: Amsterdam

I have many different XP boards in my spare box and the solder pad size and position vary a bit, to the point that on some the electrical pads are too far to the middle to fit the Luxeon V at all. Perhaps the Q8 board is one of those Smile

Tom E
Tom E's picture
Offline
Last seen: 16 min 20 sec ago
Joined: 08/19/2012 - 08:23
Posts: 12136
Location: LI NY

Just ordered 3 mounted on the 16 mm's from Led4power. That looks wayy too challenging even for me to mount on a XP board.

Just checked - these are 4.0 x 4.0 mm, bigger than XP's, smaller than XM's. Soooo, guess stock centering pieces won't work?

led4power
led4power's picture
Offline
Last seen: 4 hours 49 min ago
Joined: 12/29/2012 - 09:48
Posts: 1119
Location: Croatia,EU

Rotating XM-L spacers should work .

led4power
led4power's picture
Offline
Last seen: 4 hours 49 min ago
Joined: 12/29/2012 - 09:48
Posts: 1119
Location: Croatia,EU

XP-L V6 3D (EE X6) vs. Luxeon V 4000K (S2+) white wall

Luxeon V 4000K beam

FmC
FmC's picture
Offline
Last seen: 4 days 19 hours ago
Joined: 03/31/2013 - 05:23
Posts: 2194
Location: Brisbane, AU

ImA4Wheelr wrote:
Been trying to join you, but the footprint is frustrating me in my chosen target, the Q8.  It looks doable.  Sorry for the off angle of the picture.  Seven reflow attempts so far.  All seemed dead on.  The last few reflows were just one emitter, the other 3 excluded.  Always shorting the positive side.  Even if I hold the emitter from where it wants to sit.

If I want to keep the stock mcpcb, I think I will have to modify the pads slightly.

 

 

Has anyone tried cutting away some of the center pad with an exacto knife?

 

djozz
djozz's picture
Offline
Last seen: 2 hours 42 min ago
Joined: 09/07/2012 - 17:04
Posts: 14962
Location: Amsterdam

Now that is proper led surgery! Big Smile
(no I have not tried that)

ImA4Wheelr
Offline
Last seen: 4 days 8 hours ago
Joined: 02/03/2013 - 14:51
Posts: 7882
Location: SC

Interesting idea FmC.  Sounds promising.

I modified the Q8's MCPCB to fit the Luxeon.  Just used a utility knife to remove the solder resist on the outside of the pads out to the overflow tabs and to remove just a slight bit of the coper trace on the inside of the pads.  It wasn't pretty, but it works.  Measured about 8.5k lumens at start up which dropped down to 8K about 20-30 seconds (wasn't timing).  I had also swapped out to the A20DP FET.  The tint as has been reported by djozz and others above is so nice.  As led4power stated, it's really hard to believe the CRI is only 70.

In addition to mcpcb's, we are going to need new isolator rings.  I ended up using some xml isolators and drilled out the Q8 reflector some.  Unfortunately, I was impatient and used a dull bit.  Messed up some of the reflective coating at the enlarged emitter holes.  Luckily, the beam pattern seems unharmed.  Just not so pretty right now.

Thanks djozz for bringing this emitter to our attention.   I think this may be my new favorite emitter.

 

EDIT:  I should note that the Luxeon V's measured above went though at least 8 reflows until I got them all properly connected. I don't know yet if all the heat hurt their performance. But at a minimum, these are tough emitters.  If I get a chance tonight, I'll get a couple beam shots.

EDIT:  Sorry folks.  It was raining last night.  Looks like it will continue to rain with the tropical storm that is moving up the coast.

djozz
djozz's picture
Offline
Last seen: 2 hours 42 min ago
Joined: 09/07/2012 - 17:04
Posts: 14962
Location: Amsterdam

That is great and perseverent work ImA4Wheelr, and some bravery is required to attack the nice Q8 board with an exacto knife, I know how wrong it can go when you cross the dielectric layer when going too deep.

For clean reaming reflector openings for fitting centering rings I succesfully use a hand reamer. Mine was a really expensive one (the brand is PB) but I never regretted buying it, I use it often in modding.

The numbers that you get are as expected exactly 4 times the numbers of my VG10 with the LV.

ImA4Wheelr
Offline
Last seen: 4 days 8 hours ago
Joined: 02/03/2013 - 14:51
Posts: 7882
Location: SC

^

Thanks for the tip on the reamer.  I haven't ever used one.  Will look into them.

Tom E
Tom E's picture
Offline
Last seen: 16 min 20 sec ago
Joined: 08/19/2012 - 08:23
Posts: 12136
Location: LI NY

I installed one of the 4000K/16mm MCPCB Lumileds L1V1 from Led4Power in a BLF KRONOS X6 SS/cu light - it has spring bypasses and looks like the stock 22 AWG LED wires.

With a VTC6 at 4.21V, measured 8.7A at the tail w/clamp meter, 2285 at start, 2135 at 30 secs, 42 kcd throw measured at 5 m. The tint is one of the best I've seen, as LED4Power said earlier. It's amazing what this LED can do, plus the drop over the first 30 secs is pretty low. I can only describe the tint as a milky white, no trace of yellow - nothing like the XP-L2's. It does appear very much like a 5B or 5D that used to be my favorite.

Arrow now has 5700K L1V1's in stock, but only in qty 1000: https://www.arrow.com/en/products/search?q=lumileds+l1v1

 

I'm now working on modding a Lumintop SD Mini with a full FET+1 or  triple channel driver and another 4000K L1 V1.

Jensen567
Offline
Last seen: 3 weeks 6 days ago
Joined: 04/10/2017 - 16:59
Posts: 491
Location: MD/DC Area USA

Finally got one of these in a light. Convoy M1 with a MTN-17dd driver. The beam is gorgeous. Probably my favorite 4000k tint without tint mixing. Very hard to believe it is only CRI R7000. If they make a CRI 90 version this will be one of the best emitters out there IMO. No tint shift at all like with XPL2.

I tried out a 6500K version, and the cold white looks good too! Not as nice to me as SST40 for 6500K, but that’s because I kind of like the purple tinge SST40 has. Luxeon V is a more pure 6500K white.

Pages