DiY LED - Cree CXA3070

SupraSPL

SupraSPL

Well-Known Member
Not that I am aware of. However the economics of running it harder than 1.4A are questionable

-large jump in driver cost
-as efficiency decreases you need more driver and heatsink to do the same job, increasing cost
-as efficiency drops the COB begins to create a lot more heat to do the same job
-as intensity rises the ability to spread the light evenly into the canopy decreases. That means we need more vertical height and the use of a reflector.
-electricity cost rises to do the same job
-COB may suffer from lumen depreciation over time

When it comes to growing lamps or any LED that will be on for extended hours everyday, it makes sense to run soft. Flashlight/headlights etc I can see running them hard when the situation calls for it.
 
Abiqua

Abiqua

Well-Known Member
I am aware of the limitations :), I have read much of yours others opinions on the subject for sure and had planned accordingly other than drivers....

but I think 1.4a is plenty for now, guess I will try to go the HLG 185-1400 and upgrade later....thanks again....patiently awaiting the China order
 
P

pepperdust

Well-Known Member
Supra, fine job your doing.. some questions if you don't mind.. or anyone who knows..

I have some XM-l2 chips.. looks to be their outdated now with the 3070 ab ? I have like 40 xml2 3000k chips no put on stars, but don't want to run them if these are super more efficient? I run the xml2 at 3.2 watts I think or 1.4 amps..

has anyone done veg testing with color spectrum? I have but haven't really concluded anything, all I know is from seed ( I think clone is very very different ) I turn the light all power, then gradually decrease as the plants get older..

no one is running the meanwell DC mini drivers??? I believe them to be super efficient, small, the actual AC to DC box runs cool and is small for how many watts you like, and they would be perfect to drive the 3070 solo with one driver per cobb


so I guess I was just wondering how much more efficient these 3070 ( maybe if I ran them at .7 amp or 1 amp ) vs. my XML2 bars at 1.4 amps... I could update the XM bars with reds which I have not done.. but just wondering a ballpark how much more efficient these are



to throw this out there, I have a suspicion that a built red / blue panel would beat out a white chip panel or veg.. but I don't like purple plants... I am finding low growth with seedling, but it kicks in with white chips in veg once they get a rootball and some leaf.. I am not happy with performance in beginning veg over a color panel as I have many of them and they do seem to outgrow the white XMl2 panels, but the XM panels are lower watt... anyone else finding not so great result sin first two weeks from seed with white chips?


thanks Supra / anyone helping
 
T

Tazbud

Well-Known Member
I'm still using a couple of DC DC drivers (via 12v solar) they are very 'efficient' I'd love a12v source to run the bud space without dramas as well but just Veg for now.

I was thinking the same abt early veg, never had dramas with early veg under MH but the white runs have all started slowly, was the same with SGS. Others seem to not have an issue with the cobs/whites so was thinking it was more a deficiency thing to dial in?

Go well :peace:
 
Last edited:
K

kkman

Member
I have been told by mouser uk that there is a chance that the cxa3590 36V will be offered in single units to purchase after the new year for around the same price. So if you can wait Id... Then again they may offer lower bins, so good luck making your mind up. :-)
 
K

kkman

Member
I was lucky to get the cxa3590 2700K bin BD and compared to the cxa3070 3000K it seems a lot brighter. So if the price does not put you off Id go for the cxa3590 36V,they do run a little bit higher amps but the drivers for the cxa3070 should work with it as well.
 
SupraSPL

SupraSPL

Well-Known Member
pepperdust said:
Supra, fine job your doing.. some questions if you don't mind.. or anyone who knows..

I have some XM-l2 chips.. looks to be their outdated now with the 3070 ab ? I have like 40 xml2 3000k chips no put on stars, but don't want to run them if these are super more efficient? I run the xml2 at 3.2 watts I think or 1.4 amps..
Click to expand...
Thank you PD :leaf:

Do you know what flux bin they are? If they are the top bin (T4) for the 3000K, then at 1.5A they dissipate 4.6W and run at 32.8% efficient. Assuming you can get them mounted on stars for a total cost of $3.80 ea, the cost is $2.50/PAR W. If you run the CXA3070 AB bin buying a 20 pack they are $50 ea. At 1.4A they dissipate 52W ea and run at 42.1% efficient (minimum). Cost is $2.28/PAR W. So in this case the CXA3070 is cheaper and creates 28.3% more light per Watt.

If you can sell the XML2s and get CXAs that is great, but if you run the XML2s soft (700mA) they are 38.9% efficient. With some added blue Luxeons it could be a nice vegging lamp.

pepperdust said:
has anyone done veg testing with color spectrum? I have but haven't really concluded anything, all I know is from seed ( I think clone is very very different ) I turn the light all power, then gradually decrease as the plants get older..

no one is running the meanwell DC mini drivers??? I believe them to be super efficient, small, the actual AC to DC box runs cool and is small for how many watts you like, and they would be perfect to drive the 3070 solo with one driver per cobb
Click to expand...
I veg with a variety of LEDs. One section is 4500K XML2s (700mA), one section is 5000K CXA3590 (270mA, 20W) and the other sections are a mixture of red/deep red/white/royal blue (700mA). They all work great to be honest. The ladies are not very picky in veg thankfully. The CXA3590 achieves 60% efficiency and cost $5.56/PAR W. It is being powered by a $2 driver from ebay LOL.

When it comes to red/white/blue versus straight white, the white does have a major advatage in terms of color mixing. When vegging LEDs are running soft and very close to the canopy the colors don't have much of a chance to mix. Whereas whites do not need to worry about that. So if you could get CXA3070 4000K AD bin or CXA3590 5000K CD bin, you would be working with the most efficient whites in the world. But if you want more spread and closer to the canopy, you could use Cree XPL 5000K or 6000K depending on how stretchy your ladies are. At 1050mA they are 48.5% efficient and cost $2.96/PAR W.
 
Last edited:
SupraSPL

SupraSPL

Well-Known Member
Nice to see more options for finding the COBS. The one LEDGroupbuy is offering is the top bin,4 step, 95 CRI 5700K. They must have chose that model with reefing in mind because it is cool white and will show colors accurately, but it does not do much for the Cannabis DIYers especially at that price. The 5700K would be good for vegging, but the high CRI filter really hurts efficiency and there is no advantage to the high CRI status in our case..

To demonstrate the poor performance of high CRi for growing,
here is a comparison of the Cree XPL 5900K vs the CXA3590 5700K 95 CRI

The CXA3590 at 1050mA puts out 51W at 41% efficiency and cost $5/PAR W
The XPL at 1.4A puts out 4.3W at 45% efficiency and cost $2.33/PAR W.

If we try to match cost:
The CXA3590 at 1.4A puts out 98W at 32.7% efficient and cost $2.87/PAR W.
The XPL at 1.05A puts out 3.2W at 48.5% efficiency and cost $2.96/PAR W.

So in summary , when it comes to growing, the performance and cost of the high CRI is abysmal compared to a standard CRI. But high CRI does have its place for human vision related lighting such as viewing an aquarium.
 
Last edited:
Castaman

Castaman

Well-Known Member
2SupraSPL, thanks again!
Just few more questions if you please.
Isn't that amperage - 1500mA in that 50w driver will be "too much" for 3070 cob?
CoolerMaster DP6-9HDSA-0L-GP - can it hold normal temp with this setup? I think overall dissipation will be ~50w? Or lower?
 
Last edited:
SupraSPL

SupraSPL

Well-Known Member
Castaman said:
2SupraSPL, thanks again!
Just few more questions if you please.
Isn't that amperage - 1500mA in that 50w driver will be "too much" for 3070 cob?
CoolerMaster DP6-9HDSA-0L-GP - can it hold normal temp with this setup? I think overall dissipation will be ~50w? Or lower?
Click to expand...
The max current for the CXA3070 is 2800mA. Running at 1400mA is about 50% of max capacity. Yes I prefer to run even lower 25-30% for my lamps, but it is very economical to run at 1400mA and based on the drivers and COBs we have available to us, that is what I recommend for most DIYers. You get 42.1% efficiency (minimum) and cost is only $2.28/PAR W. That is about half the price we used to pay for our red/white/blue setups and much higher efficiency.

Any decent CPU cooler will work great at 1.4A and keep the COB plenty cool (probably Tj 55-60C)
 
indianajones

indianajones

Well-Known Member
my vero 29 runs at 30c at the Tc measurement point indicated
in the PDF when running at 1880mA. is that normal for an alpine
11 plus or am i interpreting the data wrong and it is coming out
extremely low? i am over driving the fan, using 500mA instead
of 300mA, which is 66% overdrive, but i want to make sure my
data seems reasonable before i continue to build based on these
principles.

could you send me your excel spreadsheets concerning efficiency
data @SupraSPL ?
 
SupraSPL

SupraSPL

Well-Known Member
IJ, I agree that number does seem very low. What is your ambient temp? I have tried several methods of measuring temp at the Tc measurement point and none of them have given me consistent results that I trust unfortunately. The photons and infrared output from warm whites interfere with the measurement and if you allow the system to stabilize and then click it off to get the measurement at that instant, it is still very tricky because the measuring device (thermocouple) could still be warmed up by the photons rather than thermal conduction from the COB package. So I have tried using infrared measurement at the very instant the light is clicked off but the temp drops so fast I have no confidence or consistency in the measurement.

I have also tried measuring the Vf change as the light warms up but we would need to know the "Coefficient of Forward Voltage " The Vero29 sheet says that number is .016V/C but apparently it does vary from COB to COB and the accuracy of your voltmeter is important for this experiment. So with your driver warmed up and your COB/heatsink cool at ambient temp, measure your Vf cold the very instant you turn it on (this can be tricky). Then measure again once it has thermally stabilized. If your Vf falls by .5V, that should represent an increase of 31.25C over ambient. So if your ambient is 25C, your Tj would be 56.25C in this example.

Another option is to use any old cheapo light meter. With your driver warmed up and your COB/heatsink at ambient, measure your light output from a given distance Then measure again from the exact same distance and angle once the system has thermally stabilized. This should give you a qualitative comparison to see how much the output has fallen. If you lose 5% output once warmed up, you can use that number to estimate your Tj. Unfortunately the Vero PDF uses case temp on this graph rather than Tj and it is another step to translate that to Tj, but it is another data point that might be useful.
 
Last edited:
SupraSPL

SupraSPL

Well-Known Member
Regarding the fan speed, it should be controlled by voltage. So if you are using at 12V PSU, the Arctic 11 fan should draw about 200mA. You could decrease fan speed by using a 9V adapter or increase it by using a 15V adapter. At 9V it might draw 150mA and at 15V it might draw 300mA (I am guessing here but will post the actual numbers later)
 
indianajones

indianajones

Well-Known Member
Dloomis514 said:
Quite a sunburn is gonna come off that! How big is the floodlight?
Click to expand...
the outer dimensions of the shell are 25.75x12.5x4.75

supra, i use an IR thermometer. ambient temp is 20-21C.
the LES itself is usually only ~70-75C after two hours. when
i measure the Tc point lights on, 30-33C. i may try measuring
Vf, but i am thinking of picking up a bench power supply for
ease of measurements

this was a great Vf tutorial video i saw
 
You must log in or register to reply here.
Top