DiY LED Vegging - Cree XM-L2 VS Cree CXA3070

Bueno Time

Bueno Time

Well-Known Member
Supra, what is the least amount of XML2 I could string on a fastech 900ma driver?

I am thinking 8 is the smallest even number of them I could run to hit the Vf min of the driver.

I think I only would need about 6 to veg with comfortably in my space but need to make sure the driver will run em.
 
SupraSPL

SupraSPL

Well-Known Member
Yep looks like 7 would be the minimum. I love those drivers, have been swapping them in little by little.

I just hooked up 6 and it is working (18.42 vf) but it could be hit or miss depending on the driver and depending on the vF of the XML2s. This driver is stronger than most (1A) but it works even after everything has warmed up.
 
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Bueno Time

Bueno Time

Well-Known Member
SupraSPL said:
Yep looks like 7 would be the minimum. I love those drivers, have been swapping them in little by little.

I just hooked up 6 and it is working (18.42 vf) but it could be hit or miss depending on the driver and depending on the vF of the XML2s. This driver is stronger than most (1A) but it works even after everything has warmed up.
Click to expand...
Thank you
 
M

mtnstream

Active Member
" I believe we will achieve much better results (than High CRI LED) by simply adding high efficiency deep reds or even just by running 3000K on its own."

IMO, this statement sums it up. Using 2-4 cree cxa 3050, 2.7k in my 1.8 sf filing cabinet will bud a single plant - WW x NL strain - scrog rock solid in 6.5-7 weeks. They're driven at about 1.4A. Next run, I added 2 - 660 nm 30 w to mix in with 2 - 3050's for a AK landrace indica sog.

I have a couple of 3070's - 5k for another design. Maybe
mix with 3070's or 3590's - 2.7 k (when available in smaller lots) + a high watt 660 nm ?

Due to legalities in my area, I can't post pics.

Great stuff ALL, watching from afar.
 
C

CannaBare

Well-Known Member
SupraSPL said:
Yep looks like 7 would be the minimum. I love those drivers, have been swapping them in little by little.

I just hooked up 6 and it is working (18.42 vf) but it could be hit or miss depending on the driver and depending on the vF of the XML2s. This driver is stronger than most (1A) but it works even after everything has warmed up.
Click to expand...
Can I ask which driver the fast tech driver is? I found one for 2.50 and it did not look right.
Could I get a link?
Thank you!

I finally finished my flower room with 16 CXA's and now it's time for veg!
 
OldnTired

OldnTired

Member
Great find!
I'm ready to build a LED fixture based on the heat sinks by Rapid Led. They are drilled and tapped for Star LEDs.
The 6" x 20" heat sink is drilled and tapped with 4 rows of 9 LEDs.
My issue is, I'm not sure what mix of LEDs/drivers to go with. My area is 2'x6'x6' LWH.
I really like their solderless LED design they have as well.
 
captainmorgan

captainmorgan

Well-Known Member
OldnTired said:
Great find!
I'm ready to build a LED fixture based on the heat sinks by Rapid Led. They are drilled and tapped for Star LEDs.
The 6" x 20" heat sink is drilled and tapped with 4 rows of 9 LEDs.
My issue is, I'm not sure what mix of LEDs/drivers to go with. My area is 2'x6'x6' LWH.
I really like their solderless LED design they have as well.
Click to expand...

BJB also makes some solderless holders for standard stars.

http://www.bjb.com/index.php?productid=212119
 
Bueno Time

Bueno Time

Well-Known Member
SupraSPL said:
http://www.fasttech.com/product/1320606-85-265v-30w-high-power-constant-current-led-driver

Awesome cant wait to see what those CXAs can do!
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Supra will that driver run 12 of these? I know you had said 36.5v vF max on them and this would be cutting it really close I would think.

http://www.fasttech.com/product/1574600-cree-xm-l2-u2-4c-1100lm-4300-4500k-led-emitter-on

Also do you know of any dimmable drivers that are inexpensive to run 2 strings of 6 or so of the XML2s? Or even one dimmable driver that can run all 12 LEDs? I know of some options that work for single CXA3070s (similar vF for a string of 12 XML2s) but they are $45+ship and thats not cost effective at that point for this fixture.
 
SupraSPL

SupraSPL

Well-Known Member
You might find something dimmable and reasonably priced on AC RC. I There may also be some good dimmable drivers on Aliexpress or similar but I have not been able to track any down. KNNA used to sell us dimmable 700mA drivers for $20 ea and they go up to 70-80vF with an efficiency of up to 93%, so it can be done. I still have a bunch of those and still use them but have not found a source to get more.
 
S

Skaumannen

Well-Known Member
I am looking into what to get for a 2x2x5 tent, and i was thinking of buying 4 cxa3070 3000k and 1x5000k all running at 1400mA. But apparantly i have missed the 50w/square feet, and 250w is then way too much. So now i am leaning more towards buying 2 of the cxa 3000k @ 1400mA and building one or two led strings with a more blue spectrum to use for early vegetation and to supplement the cob's. I only have space for one small growspace, and i have to grow from seed, so i would like to build a light setup that can work throughout the life cycle of the plants. But i could always put different switches on the different lights.
I am new to growing so any input is much appreciated.
 
SupraSPL

SupraSPL

Well-Known Member
Steves LEDs is now offering the Luxeon ES royal Blue N4R bin which is a new high bin. At 700mA it is 60% efficient minimum, up from the previous M4R bin which was 55%. There is a discount code on the site that makes them $2.49 ea. Nice to see things improving. I use these in my vegging and flowering lamps but all mine are M3R and M4R.

For those who have not heard, another somewhat new addition that can bring our RWB lamps to a new level, the Cree photo red 660nm are now the highest efficiency deep reds available, 42.4% at 700mA. Cutter has them and I think Digikey as well. You can get them in a variety of wavelengths to avoid saturation, 650, 660 and 670nm.

LEDGroupbuy recently added the Cree XPE2 630nm red P3 bin to its lineup. From my math they are no improvement over the XPE 630nm P3 bin, but maybe in practice they would be? Should be easy to find out since we could any old light meter to compare them as long as the wavelength is very similar.
 
SupraSPL

SupraSPL

Well-Known Member
Thnx POS, I love greens for accent lighting and the lime is an interesting wide range. The amber would be good for "before bed" lighting since they have discovered that blue interferes with the circadian rhythm. They might be worth experimenting with in the grow room, especially if the efficiency is above 30%
 
S

Scornfulheal

Active Member
@SupraSPL

You mention now that Cree XP-L 5700k V2 is a good veg/clone chip.

I have ~1.9 sqft flower area that I have 2 CXA3070 3000k V4 chips that I will run (1 per sqft) at 900-1050 mA on the Arctic coolers. These LEDs should work on their own for flowering, and I always have the option to add Red/Blue strings as supplement in the future.

Is the XP-L 5700k a good precursor for flowering with CXA 3070 3000k? Should I do any sort of ratio with white, blues and reds? I thought I heard you mention something like 4 XM-L2's U2-4C + 1 Luxeon ES Royal Blue per square foot running at 1w each for a total of 5w (4:1 ratio) is a decent spectrum. The U2-4C's are a warmer color though.

If I am going seed - > flower in one space (1.9 sqft) should I consider veg a lower sqft to figure its wattage? For example, I use 1.9 sqft for determining wattage for flower. Should I then use ~1 sqft to determine wattage for veg in the same place? This would almost reduce my veg wattage in half if so, and in turn reduce the number of heatsinks and chips needed.
 
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