Thinking of a new light ..

Gathering ideas and parts for my new light ....

2x panels .Each 100 Watts ( 2x 50 Watt Cobs )...

Parts (for each panel ) :

-2x Heatsink Aluminium 1061 200x160x40 mm
- 3x Cree CXA 3050 cob led ( 5000°K 70 CRI -3000°K 90 CRI -2700°K 90 CRI )
-3x IDEAL Chip-Lok Array holders for CXA 3050
-2x MeanWell LPC-60-1400 AC/DC CC led drivers .
- Arctic Silver Epoxy
-2x 120mm Ball Bearing Fans
- 1x 12 V psu
- DPDT switch for switching between VEG/Flower mode ( NW 5000 or WW 2700 ,with WW 3000 as main light engine)

DoublePoleDoubleThrow Switch .
An example (slide switch...I prefer toggle switches ...... )

light mod-E-ling ...

So what do you think is the right reflector angle for this setup? Or good as is?
Much easier than single lower power leds, mucho time saver. Not completely sold on cobs yet..almost

Positivity said:

So what do you think is the right reflector angle for this setup? Or good as is?
Much easier than single lower power leds, mucho time saver. Not completely sold on cobs yet..almost

Click to expand...

Well ..COBs....
I've to try them !

Anyway ..

115° half power angle ?
Fantastic !!!
Could not get better !!!

I've tried the 80° from Oslons and the 120-130° from generic leds ..
I like leds closer to canopy ...I disliked the 80° of the Oslons ..
150° is way wide (oslons 150 )..
130° is good ...
115° is almost there !

I do not like lenses..not because of ' religious ' reasons ...
I've plenty of reasons not to utilise them in my tent ...

With COBs ?

One more ...
VOCs .....

I'm thinking of a pwm dimming circuit to automatically control the two fans of each panel ...

The 555 timer and a IRF530 mosfet will do the job ...
Instead of a pot for manually controlling the duty cycle of the square wave output ..
Place a NTC thermistor ..
Or even better a silistor ,which has a more linear resistance-temperature response...
Guod ,might give a hand of help , on that one ...

I wish a had found a better driver option ....
I do not want the " main ac/dc psu & Dc/Dc cc bucks " option ...

But I didn't find any driver as I wanted to be ...

From AC to 1000-2000/2500 mA ,30-40 VDC ,>55 Watt ....
Any suggestions ???

( the other option was the dimmable Recom RACD-60-1200A ..But only 1200mA max ...
& Slightly better efficiency.... 88% vs 85% of the MeanWell LPC-60-1400 ..)

And the chosen spectrum seems good enough..

NW 5000K 70CRI + WW 3000K 90CRI for vegging ...
And ...

WW 2700K 90CRI + WW 3000K 90CRI for producing ...

No spectral data for 2700 K from cree.. But I can imagine it,more or less ...
Look the purple curve ?
Beautiful ...Ain't so ?

Still I'm not sure about the 5000K ..Too much blue and green ?
But i like it cause of the -relatively-short wl at blue region ...

And some thermal calcs ..


The heatsinks I use ,are quite massive..
200 mm x 160 mm (wide ) x 40 mm .16 fins ,10 mm base .( 30 mm fin height )
2 lbs (1990 gr ) alum alloy 1061 .

They are an exact size/shape-wise 'copy' of the SK 85 from Fischer Electronics ..
( Rth at 200 mm ,passive : ~ 0,55 C/W )
http://www.fischerelektronik.de/web_fischer/en_GB/heatsinks/A01/Standard extruded heatsinks/PR/SK85_/$productCard/dimensionParameters/index.xhtml







So ..passive I should expect ,the temperature to rise about ~30 °C ,(average )with these heatsinks ...

Close to Cree's example ...With the Aavid 6 in (15.24 cm) X
9.75 in (24.77 cm) X 2.28 in (5.79 cm) heatsink ...
+47°C ...



But the ones I use have thicker and shorter fins ,than the Aavid of the example (almost same size )
So they are more efficient ...

Active ,with air flows of >5 m/sec,I should expect 10°C or less temperature case-ambient difference (Tc-Ta )..

You want to keep all silicone away from any optics. The outgassing from even the bracelets people wear to support a cause can fog over the chips.

stardustsailor said:

light mod-E-ling ...
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Click to expand...

You only need a single pole switch. The ground side doesn't need to be switched. Better yet, switch the feed line to the driver.

Hey SDS sounds like a cool build you got going. As you probably know the curves in the Cree datasheet are not relative to each other, they simply pegged the highest point at 100% so it makes the high CRI look much better than it actually is. Here is the actual chart thanks to Mr Flux caclulus:


Also worth mentioning, the CXA3070 3000K Z4 bin is out there floating around. It is 39.3% efficient at 1400mA versus the CXA3050 2700K W2 bin (80 CRI) which is 30.4% efficient. That is a stunning 30% increase in efficiency and possibly 40% increase over the 93 CRI 2700K. Hope it helps you out, good luck!

I remember this chart. Great point. It looks like the 3000K, 80CRI one has more total photon flux output (uMol/s) than the 93CRI. If supplementing with 660nm leds, the 80CRI version looks perfect for cranking out amber for penetration, while the 660nm coat the top canopy in red.

660nm sears the steak while amber cooks the middle to a nice medium rare.

The only disadvantage (maybe?) I can see is that the 80CRI one has less 730nm.

SupraSPL said:

Hey SDS sounds like a cool build you got going. As you probably know the curves in the Cree datasheet are not relative to each other, they simply pegged the highest point at 100% so it makes the high CRI look much better than it actually is. Here is the actual chart thanks to Mr Flux caclulus:

Also worth mentioning, the CXA3070 3000K Z4 bin is out there floating around. It is 39.3% efficient at 1400mA versus the CXA3050 2700K W2 bin (80 CRI) which is 30.4% efficient. That is a stunning 30% increase in efficiency and possibly 40% increase over the 93 CRI 2700K. Hope it helps you out, good luck!

Click to expand...

I'd like to see a high cri cob grow. Sometimes ya never know how something will work out till you give it a whirl. But the huge efficiency hit doesn't look good

Think it was pico saying he was liking the high cri...if their was a better selection of cree cobs available I'd give them a try

SupraSPL said:

Hey SDS sounds like a cool build you got going. As you probably know the curves in the Cree datasheet are not relative to each other, they simply pegged the highest point at 100% so it makes the high CRI look much better than it actually is. Here is the actual chart thanks to Mr Flux caclulus:

Also worth mentioning, the CXA3070 3000K Z4 bin is out there floating around. It is 39.3% efficient at 1400mA versus the CXA3050 2700K W2 bin (80 CRI) which is 30.4% efficient. That is a stunning 30% increase in efficiency and possibly 40% increase over the 93 CRI 2700K. Hope it helps you out, good luck!

Click to expand...

I'm very well aware about the ' normalised ' to 100% ,spectrum relative comparison graphs ....


Still you 've a good point there ...

Maybe I should change the 'core' ..
Yes ,indeed the 3070 3000K80 CRI is rich in the top RQE wls ( 590-620 nm ) ..
And still superior than the 93 CRI up to 650 nm ..(640-650 is my favourite red region ..)

But further from there up to the 730 region ,the 93 CRI ,is more flowering-oriented ...
@ ~ 660 nm the 80 CRI has a bit more than 0.02 umol/sec,while the 93 cri is a bit below 0.03 ..
Is the difference worthy the efficiency loss ?
Maybe ..
Maybe not ...
Maybe instead have the old oslons ,shed some deep red light ...

So it is then ....

All cobs will be cxa 3070 ...(I wonder where I'll find them ..Mouser says 8 weeks waiting ...)

2x 3000K 80 CRI and 1x 5000K 70 CRI ...

make a pictorial of how you build it if it isnt too much trouble

And that means vegging with NW + WW cxa's
and flowering with 2x WW ...

38.5 volts ,up to 2.8 A ....

A dimmable driver would be nice ,there ,now ....

Meanwell offers plenty of (rather expensive ) options ...

Up to now ,I like the pcb ,Power Factor Corrected HLP-80H-42 ...
dimmable up to 1950 mA ,42 volts max..

http://www.meanwell.com/search/HLP-80H/default.htm
@ 36€ each ....

Another 'heavy-duty'/waterproof option is the HLG-80H-42 B..
For double the price ,same 1950 mA,dimmable and 1% more efficient than the open/pcb type ...

http://www.meanwell.com/search/HLG-80H/default.htm

spazatak said:

make a pictorial of how you build it if it isnt too much trouble

Click to expand...

When I'll get all the parts needed ,be sure I'll make one...

Thnx for the link SDS I will check out that driver. I am looking for something dimmable and powerful enough to run a CXA3070 hard for photography.

As far as constant current drivers go, here are 4 that are of interest:

I bought and tested this $20 1700mA dimmable driver with a CXA3070 unfortunately it can only go up to 900mA because the vF range maxes out at 36vF.

I tried the $10 Fasttech 1600mA driver and it was able to deliver 1200mA to the CXA3070 at 90-91% efficiency. It was not a vF problem, just a much lower output than advertised. Also, It is not power factor corrected.

The Meanwell LPC-60-1040 will deliver the promised 1400mA for $20, 88-90% efficient and IS power factor corrected.

I have one of these $13 1500mA drivers on order, can't wait to test it. It claims a vF range up to 39. I will report back its performance.

stardustsailor said:

Yes ,indeed the 3070 3000K80 CRI is rich in the top RQE wls ( 590-620 nm ) ..
And still superior than the 93 CRI up to 650 nm ..(640-650 is my favourite red region ..)

But further from there up to the 730 region ,the 93 CRI ,is more flowering-oriented ...
@ ~ 660 nm the 80 CRI has a bit more than 0.02 umol/sec,while the 93 cri is a bit below 0.03 ..
Is the difference worthy the efficiency loss ?

Click to expand...

As much as I love that chart, it is just a general comparison of CXA curves. You have a valid concern but have no worries, if we were to plot a chart using the CXA3070 Z4 3000K 80CRI versus the CXA3050 U4 2700K 93CRI, the 40-50% boost the CXA3070 gets would overtake the high CRi in the deep red/far red range. Incidentally, I could not find any source for the high CRi CXA3050. Did they sell out or just have not been made available yet?

SupraSPL said:

Thnx for the link SDS I will check out that driver. I am looking for something dimmable and powerful enough to run a CXA3070 hard for photography.

As far as constant current drivers go, here are 4 that are of interest:

I bought and tested this $20 1700mA dimmable driver with a CXA3070 unfortunately it can only go up to 900mA because the vF range maxes out at 36vF.

I tried the $10 Fasttech 1600mA driver and it was able to deliver 1200mA to the CXA3070 at 90-91% efficiency. It was not a vF problem, just a much lower output than advertised. Also, It is not power factor corrected.

The Meanwell LPC-60-1040 will deliver the promised 1400mA for $20, 88-90% efficient and IS power factor corrected.

I have one of these $13 1500mA drivers on order, can't wait to test it. It claims a vF range up to 39. I will report back its performance.

Click to expand...

Thanx for the links,also ..
I'm still in the search for driving the 3070's ..

But i like very much that meanwell pcb thing ...
And it seems that we share common interests ,beyond leds ..
(photography .. What a passion,eh ? )
Anyway ...