C.O.B.S.S.L. News and Articles

[GroErr]

Be careful.....the IR in the Foscam cameras are 730nm. Don't leave them on all the time or in auto mode. Manually turn them off and on.

You mean be careful of hermies or the like? I have 4 of them, oldest is about 1 1/2 years when I started indoor, that one was in my combined veg/flower cabinet in really close quarters (2x4x5.5' cabinet) until I built the flower room. Haven't had any signs of issues/hermies, I question the whole light leak theory period unless maybe it's extreme.

Hey, the camera's like 2ft from my Blue Dream, perhaps THAT'S the secret to faster flowering, IR 24/7? lmao

Just kidding... really. The software has an option now to schedule when IR works or not, just haven't bothered since I haven't seen any issues related to it. Cheers.

 

[stardustsailor]

Yeap..As I've suspected ...
High CRI "suck".....
GO and see for yourselves...

 

[tenthirty]

You mean be careful of hermies or the like? I have 4 of them, oldest is about 1 1/2 years when I started indoor, that one was in my combined veg/flower cabinet in really close quarters (2x4x5.5' cabinet) until I built the flower room. Haven't had any signs of issues/hermies, I question the whole light leak theory period unless maybe it's extreme.

Hey, the camera's like 2ft from my Blue Dream, perhaps THAT'S the secret to faster flowering, IR 24/7? lmao

Just kidding... really. The software has an option now to schedule when IR works or not, just haven't bothered since I haven't seen any issues related to it. Cheers.

Stretch and funny flowering foxtailing etc.

 

[GroErr]

Stretch and funny flowering foxtailing etc.

Yeah, there's not enough output in these to worry about these cam's doing that. This Blue Dream I'm running will be the closest any flowering plants get to that Cam in the main flower room. Will look for any weird growth but I expect I would have seen something by now running them in the smaller cabinet for a long time. They definitely don't cause stretch in veg, the cam in the veg cabinet is 12" or less from top of the canopy, nodes are so dense/tight that when I can, I stretch them at 14/10 for a week or so to open them up a bit before flowering.

 

[AquariusPanta]

http://www.ledsmagazine.com/articles/2014/10/bridgelux-announces-d-cor-series-leds-with-optimized-cri-and-gai-performance.html

http://www.ledsmagazine.com/articles/2010/06/assist-alliance-develops-new-metric-for-color-properties-in-retail-lighting.html

http://www.lrc.rpi.edu/programs/solidstate/assist/pdf/AR-ColorGuideforRetailLighting-March2010.pdf

http://www.lrc.rpi.edu/programs/solidstate/assist/pdf/AR-SpecifyColorRec-March2010.pdf

http://www.ledsmagazine.com/articles/2010/06/nist-develops-cqs-alternative-to-cri-for-color-quality-specs.html

http://apps1.eere.energy.gov/buildings/publications/pdfs/ssl/cqs_rationale_06-10.pdf

pd...
http://www.photometrictesting.co.uk/File/blog_LED_colour_difference.php

...e actived... too faster...

saludos

"There are several problems with CCT as a measure of the color appearance of the light emitted by a source. First, CCT is a potentially confusing metric because higher color temperatures are associated with “cooler” color appearance, and lower color temperatures are associated with “warmer” color appearance.5 This counterintuitive relationship between CCT and tactile sensation appears to be an artifact of the association people have between the radiant warmth and the yellow color of an open flame."

I've been trying to wrap my head around that concept for awhile now. How can 2500K be warmer than 6000K, which is considered cool? I guess "cool" blue indicates a hotter flame temperature when cooking, while the "warm" orange/yellow flame indicates lower, so this could help justify the CCT. If they didn't use the words warmer and cooler, then most edumacated people would nod in understanding.

The Color Quality Scale: It's a SLAM DUNK!

Thank you for the news update TinSalmon

 

[SupraSPL]

The confusion ultimately comes from the reflected color of water. Humans associate blue with "cool" because of the reflected color of water and ice. Fire is orange because of its emitted color. In order for coals to appear white or blue they would have to be hotter.

So this confusion has led to all of our showers and sinks using blue to represent cold and red to represent hot. This is very dangerous because if aliens try to use your shower they will be scalded

 

[Dloomis514]

The confusion ultimately comes from the reflected color of water. Humans associate blue with "cool" because of the reflected color of water and ice. Fire is orange because of its emitted color. In order for coals to appear white or blue they would have to be hotter.

So this confusion has led to all of our showers and sinks using blue to represent cold and red to represent hot. This is very dangerous because if aliens try to use your shower they will be scalded

Then they should just go back to their original solar system

 

[AquariusPanta]

If these aliens are anything like the aliens off of "Signs", than they probably ain't going nowhere near the shower... the dirty bastards!

 

[stardustsailor]

CXA3070 vs VERO29 .
( CCT 3000° K - 80 CRI )

CXA3070-0000-000N00AB30x vs BXRC-30E10K0-L-xx

Both driven at 2.1 A and with Tc=25°C .



The way I see it ...
Vero 29 is the winner .
Higher radiometric efficiency ( +5,55% ),
along with a better -somewhat- light quality (at least for the ' flowering stage ' ).

Cheers.

 

[salmonetin]

https://www.rollitup.org/t/bridgelux-vero-29-led-test.702193/

saludos

 

[SupraSPL]

Hello SDS welcome back! Regarding Vero29 vs CAX3070, I have been wondering what is the actual Vf because there is a discrepancy between the curve and the chart in the same Vero PDF. The typical Vf (Tj 25C) at 2.1A is either 38.6 (chart) or 39.63 (curve). You referenced the Vero Vf at Tc25C but the Vero is misleading here because they are using pulsed measurement so TC=TJ 25C. But the CXA at 2.1A, Tc25C equals Tj of 60C because they are using steady state measurements. So to make things fair, at Tj 50C the Vero29 Vf would be 39.11 using the curve they give us and puts out 8474 lumens minimum at 2.1A.

Using minimum figures for both and Tj of 50C (impossibly low Tj at 2.1A I recognize) I get 117.5lm/W (36.15%) for the CXA3070 and 103.2 lm/W (32.25%) for the Vero29.

I will recalculate using the "typical figures" to try and get a closer comparison and I have a Vero18 on hand that I can check the Vf to see if it more closely follows the chart or the curve.

All that said, the Vero29 does hold up reasonably well at high dissipation wattage, but then again Vero29 is a 175Watt COB versus the 120W CXA3070.

I have a Vero18 on hand so I will do some testing to try and figure out which set of Vero Vf data is the correct one.

 

[bicit]

Welcome back SDS, and what a grand entry at that. If you don't mind me asking, how do those numbers look at 1.4 or 0.7 amps?

 

[stardustsailor]

Hello SDS welcome back! Regarding Vero29 vs CAX3070, I have been wondering what is the actual Vf because there is a discrepancy between the curve and the chart in the same Vero PDF. The typical Vf (Tj 25C) at 2.1A is either 38.6 (chart) or 39.63 (curve).

At chart from the revised pdf (9/12/2014 ) of Vero 29 the typical Vf at 2.1 A is ~38.6 Volts ,
(Typical curve ) .

You referenced the Vero Vf at Tc25C but the Vero is misleading here because they are using pulsed measurement so TC=TJ 25C. But the CXA at 2.1A, Tc25C equals Tj of 60C because they are using steady state measurements. So to make things fair, at Tj 50C the Vero29 Vf would be 39.11 using the curve they give us and puts out 8474 lumens minimum at 2.1A.

For led arrays,at general : Tc=Tj = Tsp

Typical DC luminous flux for Vero 29 is 8613 Lm at 2.1 A and Tc=85 C .
( Minimum is 7760 lm @ 2.1A / Tc =85 C )



Vf = 37 V


Typical DC luminous flux for CXA3070 AB is 8359 Lm at 2.1 A and Tc=85 C. (Vf=38.87 )



So .....

At TC=Tj=Tsp = 85°C :

Using minimum figures for both and Tj of 50C (impossibly low Tj at 2.1A I recognize) I get 117.5lm/W (36.15%) for the CXA3070 and 103.2 lm/W (32.25%) for the Vero29.



I will recalculate using the "typical figures" to try and get a closer comparison and I have a Vero18 on hand that I can check the Vf to see if it more closely follows the chart or the curve.

All that said, the Vero29 does hold up reasonably well at high dissipation wattage, but then again Vero29 is a 175Watt COB versus the 120W CXA3070.

I have a Vero18 on hand so I will do some testing to try and figure out which set of Vero Vf data is the correct one.

Actually ,Vero 29 it turns out to be a tad more efficient than cxa3070 AB bin,'cause of that also.
It's a more powerful led array.Thus driven lower than its max pwr dissipation ,
it outperforms almost any less powerful COB,driven at same If.

Cheers.

 

[SupraSPL]

At chart from the revised pdf (9/12/2014 ) of Vero 29 the typical Vf at 2.1 A is ~38.6 Volts ,
(Typical curve ).

Right, but the curve in the same PDF does not agree:

For led arrays,at general : Tc=Tj = Tsp

In a steady state measurement (as CXA), Tj = Tc + 21.3C (the thermal resistance from 82W of dissipation through the COB package). So at 2.1A, Tc25C = Tj46C before thermal interface and heatsink losses are taken into account.

In a pulsed measurement (as Vero) Tj=Tc because there is no time for the thermal path to stabilize. This makes the Vero appear to have 4% more output if this difference is not taken into account.

From the CXA3070 PDF:
"The maximum current rating of the CXA3070 is dependent on the case temperature (Tc) when the LeD has reached thermal equilibrium under steady-state operation."

So when Cree refers to steady state operation they are assuming thermal equilibrium, meaning the Tc does not equal Tj.

 

[stardustsailor]

Welcome back SDS, and what a grand entry at that. If you don't mind me asking, how do those numbers look at 1.4 or 0.7 amps?

Same thing .
For same Tc/Tj and If ,either 700 mA or 1.4A ,
Vero 29 outperforms slightly the CXA3070.

For example :
If=700mA
Tc =Tj=Tsp = 85 °C

Vero 29 .

Lum.Flux = 3212 lm



Vf= 33.2 V at 700mA / Tc=85 C (min Vf curve , because Vf drops as TC/Tj rises ...)

CXA:



So :


Cheers.

 

[stardustsailor]

Right, but the curve in the same PDF does not agree:
View attachment 3290070
In a steady state measurement (as CXA), Tj = Tc + the thermal resistance of 80W of dissipation through the COB package. So at 2.1A, Tc25C = Tj60C at the least.

In a pulsed measurement (as Vero) Tj=Tc because there is no time for the thermal path to stabilize. This makes the Vero appear to have 5-10% more output than the CXA if this difference is not taken into account.

From the CXA3070 PDF:
"The maximum current rating of the CXA3070 is dependent on the case temperature (Tc) when the LeD has reached thermal equilibrium under steady-state operation."

So when Cree refers to steady state operation they are assuming thermal equilibrium, meaning the Tc does not equal Tj.

There's no such graph in the new pdf of the VERo 29.
(Revised spec sheet :
Bridgelux Vero 29 Array Series Product Data Sheet DS33 REV E (9/12/2014) )

Values for Vero 29 are not from pulsed operation ,but from after reaching thermal equilibrium.
(Steady state ).

Furthermore:
.

 

[bicit]

Same thing .
For same Tc/Tj and If ,either 700 mA or 1.4A ,
Vero 29 outperforms slightly the CXA3070.

For example :
If=700mA
Tc =Tj=Tsp = 85 °C

Vero 29 .
View attachment 3290077
Lum.Flux = 3212 lm
View attachment 3290081


Vf= 33.2 V at 700mA / Tc=85 C (min Vf curve , because Vf drops as TC/Tj rises ...)

CXA:
View attachment 3290085


So :
View attachment 3290086

Cheers.

So cheaper, easier to find, easier to work with, AND more efficient? Sounds like bridgelux is on a roll with the vero series.

 

[stardustsailor]

Further more ....
CXA has it's diodes placed on a ceramic substrate :
http://www.americanberyllia.com/BeO_conductivity.html?gclid=CjwKEAiAvvyiBRDzrYuuldy6wB8SJABPJWObu39xRcDGggI9UxNwNU9HROMr1xaZY5gamYxbomh-3BoCSM7w_wcB

Even if the ceramic used is the highly expensive BeO (Beryllium Oxide ),will have a thermal conductivity of a tad more of
250 W/mK ..(~265 W/m.K )

Vero 29 uses copper as substrate ...
Average ther. conductivity of 385-400 W/m.K ...

Vero 29 has better thermal conductivity than CXA 3070 and of course less thermal resistance.
That's another reason for higher performance,also.

cheers.

 

[stardustsailor]

So cheaper, easier to find, easier to work with, AND more efficient? Sounds like bridgelux is on a roll with the vero series.

Yeap.
That's right !

 

[SupraSPL]

The CXA series excels when underdriven. So if the CXA is more efficient than Vero at 2.1A, it is a lot more efficient at 1.4A and more still at .7A. It is also slightly cheaper. According to my math (minimum figures), at .7A the CXA is 49% efficient and the Vero 29 is 37.5% efficient. At .7A the CXA cost $4.05/PAR W and the Vero cost $4.24/PAR W

Because we tend to run our COBs relatively cool and we prefer a wide spread of light, the superior thermal resistance of the Vero package does not come into play, but the superior current droop characteristics of the CXA do. This makes the CXA more suitable to our application IMHO and it shows up very noticeably on paper. For example I have demonstrated that it is cheaper