DiY LED - Cree CXA3070

SupraSPL said:

Good info thnx SDS. So based on this, the 40vF 1550mA drivers should be no problem for any of the CXA3070s.

Click to expand...

A hard guess of mine is that for CXA 3070 Z4 ,max Vf=42 V .
And that's only when Io=2800mA and Tc is way low ...
Practically ...Almost impossible ,in real life applications ..
More realistic is max Vf= 40.5 -41.5 V ...(Io=2800mA )

Positivity said:

Sds..I thought I had a lot of fan power at 10w. Hmmm..my fans should have been on the ends right over the hotspots.
Still would have had plenty of air making it to the middle. Would have been easy to do shucks..

Thing I'll just roll with it for now

Click to expand...

Keep that rule in mind : "Coolest state of airflow ,to hottest part of heatsink. "

Then you can design ,where to place the fans and if they are going to blow or suck ...
The more power the better (for cooling ).as also the more power the worse .(for noise / overall el. efficiency ).

SupraSPL said:

Good info thnx SDS. So based on this, the 40vF 1550mA drivers should be no problem for any of the CXA3070s.

Click to expand...

Practically ,yes.
No problem,at all.

And just for the ' fun ' of it ....


The die lay-out of a Cree CXA 3070 3000°K Z4 led Array (Chip On Board ) :


132 dies .....



(Photos taken at 90mm zoom ( 35mm equiv. ) ,-5 EV , & 8x ND filter ,& a pair of Ray-Ban 'shades' in front of ND filter ,F22 and CXAs @ 350mA ..And still I got blinded ,looking through the viewfinder of my SLR , FGS !!!! )

Cheers.

I am curious... There are some interesting drivers of meanwell but they have not enough voltage, but enough amps. What happens with the efficiency of a 3070 when you use such a driver? 1400 ma and only 36 volts (in stead of 38/40)?

@stardustsail that is a fine piece of art!

Those Mean Well's should go a little over the rated voltage AFAIK, there's an over voltage shutdown listed in the spec sheets. Someone with experience could confirm, but I think they'll be fine running a little overvoltage - current might just sag a little.

Hey Sup,

Keep on' keeping on...mtnstream

Here's something interesting. I know it can't be used with the CXA but still interesting.

http://www.makersled.com/products/makerscontroller/

a little question,can be mounted in series two cob 3070 with a single power supply?
for them to go to 750 - 1 or a maximum of 1.4 mA, which power supply with features such as the use?
someone has tested?
right now i use in Luxeon Rebel setup 2 x LPF-60D-54 (162.5x43x32mm (LxWxH))
I want to understand whether this power supply can produce something useful to this series of COB, or not.
inside my lamp the space of power supply it's limited to this dimension...

captainmorgan said:

Here's something interesting. I know it can't be used with the CXA but still interesting.

http://www.makersled.com/products/makerscontroller/

Click to expand...

Yeah I was looking at reef controllers to use with a 730nm flowering initiator. I wanted to use it to control the 730nm as soon as the main lights went out and to keep them on for 5-10 minutes. Unfortunately, for what I wanted to use them for I think it was overkill. A rather expensive solution that can be handled by a regular timer.

What other uses can you think of? I suppose you could set up a similar system to the intelligro panels that apparently simulate the changing spectrum of light throughout the course of the day. As to whether or not it would make a difference I cannot say but it would be interesting to see. I guess you could also use it to control blue lighting to be used at night as there is speculation that blue light will continue to be used by the plant without effecting the flowering cycle.

Rooster99 said:

Yeah I was looking at reef controllers to use with a 730nm flowering initiator. I wanted to use it to control the 730nm as soon as the main lights went out and to keep them on for 5-10 minutes. Unfortunately, for what I wanted to use them for I think it was overkill. A rather expensive solution that can be handled by a regular timer.

What other uses can you think of? I suppose you could set up a similar system to the intelligro panels that apparently simulate the changing spectrum of light throughout the course of the day. As to whether or not it would make a difference I cannot say but it would be interesting to see. I guess you could also use it to control blue lighting to be used at night as there is speculation that blue light will continue to be used by the plant without effecting the flowering cycle.

Click to expand...

If you used the CXA's for your main lighting and used this controller to add UVA,blues,reds,deep reds and the 730 stars and control them to mimic the sun would be interesting to try.

captainmorgan said:

Here's something interesting. I know it can't be used with the CXA but still interesting.

http://www.makersled.com/products/makerscontroller/

Click to expand...

Nothing that can be done with a 2x16 LCD screen and an Arduino Uno ...
Maybe an external timing IC breakboard ,might be needed also...
About $50 total ..
Even less ,if board is made 100% DIY ..(AtmelMega 328P chip+Crystal 16Mhz +resistors+7805 reg+..+etc )..
Plenty of (almost complete ) ideas from the 'aquarists' world ...
Plenty,enough ...

Examples :
http://www.plantedtank.net/forums/showthread.php?t=147328
http://forum.arduino.cc/index.php/topic,65476.0.html
http://www.instructables.com/id/Bird-cage-LED-daylight-simulation-system/step2/Power-the-Arduino-and-LEDs/
http://www.nano-reef.com/topic/269070-reef-daylight-controller-v3/

Check this =>

For Kessil A360 pendants, DIY LED setups, and AquaIllumination fixtures.


6-channel dimmable control (3 x 3.5mm jacks)
0-10v analog, PWM, serial
Sunrise, sunset, weather effects (thunderstorm, etc.)
Cross-channel dimming for sun simulation across multiple lights (sun “rises” across tank)
Bluetooth 4.0 Expansion chip available (Android, iPhone control)
Open-source, Arduino compatible

Click to expand...

http://www.canreef.com/vbulletin/archive/index.php/t-97510.html

And plenty more :
http://www.thereeftank.com/forums/f76/arduino-controller-project-190754.html

...
And yes ...Can be modified to work with CXAs as also with any other led ...
As long as CC led drivers used ,are PWM dimmable...

Controller then has to do the 'time -keeping ' (have a clock sub-routine/hardware ) and
be the PWM singal generator ( frequency ,according to CC led driver's specs ) ...

Then the rest of " buttons,weather/dawn/dusk,display ,etc " programming and hardware ..

to try to solve my problem of space inside the lamp, i see this ps:
INVENTRONICS EUC-052S070DV
700 mA - 90 ~ 305 Vac - 38~75 Vdc - 52 W
with these characteristics it's possible to drive 2 x 3070 in series at 700mA?

zangtumtum said:

a little question,can be mounted in series two cob 3070 with a single power supply?
for them to go to 750 - 1 or a maximum of 1.4 mA, which power supply with features such as the use?
someone has tested?
right now i use in Luxeon Rebel setup 2 x LPF-60D-54 (162.5x43x32mm (LxWxH))
I want to understand whether this power supply can produce something useful to this series of COB, or not.
inside my lamp the space of power supply it's limited to this dimension...

Click to expand...

Sounds like this is what your looking for It will run 2 3070's And dim http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_2189265_-1 That is the B version though if you want the pot to adjust current on the driver itself You want to get the A version

zangtumtum said:

to try to solve my problem of space inside the lamp, i see this ps:
INVENTRONICS EUC-052S070DV
700 mA - 90 ~ 305 Vac - 38~75 Vdc - 52 W
with these characteristics it's possible to drive 2 x 3070 in series at 700mA?

Click to expand...

At 700mA the CXA 3070 array ,initially (TC=25C ) will have a Vf of ~35 Volts ...
Later as it will heat up,it's Vf will drop to about 34.6 Volts (Tc=55C )

The driver of course it can drive two CXA3070 connected in series ...
As initially ,the will drop the voltage to about 70 VDC ...

Thing is this ....

If for some reason ,one of the CXAS fails and still the circuit remains closed ....
The lower V limit of the driver is 38 Volts ...
The ( hot ) remaining CXA will drop only 34.6 V ..
The driver can't supply that low voltage ....
It will (try to ) supply the single CXA with 38 VDC ...
At that voltage ,current that passes through the CXA is ~ 1700mA ...

If the driver has an overcurrent protection ,then it will kick on ...
If not ...
The driver will probably be fried ,in a matter of seconds or maybe minutes ..

Another case will be ...

If the driver for some reason outputs 75 VDC to the single(remaining ) CXA ...
Ok ..then you know what happens to the CXA ...
Flyes up to the led's heaven ...
You will see the 'smoke' ...

And I hope Supra will excuse me ,but I think that,this thread,is actually the best place
for posting some ' notes ', that might become handy ,for DIY projects ,regarding the CXA3070 Z4 bin .

Three different Tc states ..
( 35-45-55 °C )

My advice is to aim for Case temperatures ,in the range of 35-55 °C ,for driving the CXA3070 up to 2A.
While the CXA will withstand up to 85°C case temperature @ 2.8A ,it's not really efficient for horticultural
purposes ...

I trust that the CXA3070 can be driven up to 2.1 A ,if case temps are well kept below 60°C ,
while still being quite efficient for growing plants .( mj included ... .... )

The all time classic "Upper operational Limit = 70-75 % of max " thumb-rule ,
applied in many fields/appliances in the world of electronics ...
(Something like the REAL MEAN SQUARE aka RMS ,which is also 0.707 ( square root of 2 ,divided by 2 )


Electrical :
Vf vs If ( aka Io of CC driver )
(very helpful diagrams ,whenit comes to chose led drivers )



Electrical Power vs Io





Radiometric Efficiency & Radiant Power
(Or 'Why is good led cooling ,so important ..." )









And the more detailed version of all ,of the above ....





CREE CXA3070 is a 'miraculous' led array ...
The 3000°K 80CRI Z4 / AB ,has amazing plant growing abilities ...
(As an 'all-around' horticultural illumination device/ light source ... )

Just keep it as cool as possible.


Cheers.

I got the rest of my LEDs in and the stars sanded down flat and the driver and pk3 thermal paste showed up today. Still no heatsinks though.

Anyone know how long it takes heatsinkUSA to ship usually? It says on the website usually the next business day its been 8 days since I ordered. I already got my stuff from China. Oh well I guess I wait (like I have a choice lol).

As soon as the heatsinks come in Im going to go to town on sanding them flat too.

Anyway things are doing ok I guess so far other than the fact the plants got too tall once again in my little tent. Plant tops were way too close to the COBs so I moved them out to the sides and angled them in towards the center a bit. Oh well I guess first run can never really be dialed.

Day 28 12/12

Yeah, LED's are a different ball game, I think I have mine dialed in now. Those are looking good. They will be top heavy for sure. I grew a plant that always stretched but it had monster buds on all of the tops. Happy growing

Bueno Time said:

I got the rest of my LEDs in and the stars sanded down flat and the driver and pk3 thermal paste showed up today. Still no heatsinks though.

Anyone know how long it takes heatsinkUSA to ship usually? It says on the website usually the next business day its been 8 days since I ordered. I already got my stuff from China. Oh well I guess I wait (like I have a choice lol).

As soon as the heatsinks come in Im going to go to town on sanding them flat too.

Anyway things are doing ok I guess so far other than the fact the plants got too tall once again in my little tent. Plant tops were way too close to the COBs so I moved them out to the sides and angled them in towards the center a bit. Oh well I guess first run can never really be dialed.

Day 28 12/12

Click to expand...

HeatsinkUSA has been pretty quick at getting orders to me. 8 days seems long for a domestic order. If you are not in the US your order should still arrive soon. You may want to check with them if it doesn't arrive soon. Also, you may be very pleasantly surprised at how little you have to do to make the surface of the heat sink perfect. Mine were practically perfect right out of the box.