Matching Drivers and COBs
- Thread starter SupraSPL
- Start date
Hello .. my English is not good, I'm going through a translator, but if I understood correctly, the sense of your question is the cooling efficiency? if so .. water cooling for the purposes of this needlessly complicated .. Just .. cpu cooler with no heatpipe paradoxically have better efficiency .. I watched in another thread, where it discussed .. Inquire cpu cooler with effect for the cpu to 120- 140 watts and you'll be fine .. excellent and cheap affairs of the box coolers intel .. look on eBay or at local computer service I bought a piece of $ 2
frica
Well-Known Member
Short answer: Yes
50W max output with 40V is 50/40=1.25A.
According to page 5 of the CXB3070 datasheet, it pulls at most 35 volt at +-1.25A
http://www.cree.com/~/media/Files/Cree/LED Components and Modules/XLamp/Data and Binning/ds CXB3070.pdf
So that driver will power 1 CXB3070 which will be driven at +- 1.25*35= 43-44 watt.
tk9119
Well-Known Member
And by the way it is a 1500 amp driver
Danielson999
Well-Known Member
Here's my understanding of it. Your PPF or 'photosynthetic photon flux' is expressed as µmol/s or micromoles per second. It tells you how many photons your light is putting out per second.
Your PPFD is expressed as µmol/m2/s or micromoles per meter squared per second. So basically your PPFD is exactly the same as your PPF except it's defined over a meter squared.
Once you know your PPF, simply divide it by the size of the area (in meters squared).
example: 400PPF divided by 1.48m^2 (which is a 4x4 tent) = 270.2µmols/sec/m^2
- to convert sqft into meters squared divide your sqft by 10.76 and you have your m^2.
klx
Well-Known Member
Use this for ppfd - http://rollitup.org/t/diy-cob-led-calculator.890214/
frica
Well-Known Member
Then it will still work, but those aliexpress/ebay drivers have pretty dodgy descriptions.
1.5A @ 40V is 60W.
Airwalker16
Well-Known Member
frica
Well-Known Member
COBs will pull less voltage at a lower current. (They also pull less volt at a higher temp)
See page 9
http://www.cree.com/~/media/Files/Cree/LED-Components-and-Modules/XLamp/Data-and-Binning/ds-CXB3590.pdf
1050mA isn't on the chart, but it looks very linear and extrapolating the graph will probably have the voltage a little less than 34v.
J Bleezy
Well-Known Member
Thank you sir. So to figure out my ppf, do I just multiply my par watts by how many micromoles a cxb3590 cd 3500k puts out per watt? Sorry for my ignorance on the subject
Someone else posted that meanwell recommended keeping the wires under 50' on the DC side. This will also depend on the ga of wire used, if smaller wire is used go a shorter distance. Are you aware the Elg series is 220v?
50' is 50 feet right? You Americans with your silly non metric system
Yes I'm aware of the 220V, we have 230V here where I live so that will be fine.
So three CXB3590 will be fine on that elg?
Yes, according to the chart on page one50' is 50 feet right? You Americans with your silly non metric system
Yes I'm aware of the 220V, we have 230V here where I live so that will be fine.
So three CXB3590 will be fine on that elg?
Danielson999
Well-Known Member
To figure out your PAR you multiply the watts of your cob/s output by the efficiency of the cob. To figure out a relatively close estimate of your PPF you take your PAR watts, subtract losses attributed to the environment (tent walls, reflectors or even worse if your lights have no boundary) which are typically 10-20% of your total PAR. Then you take the PAR remaining and multiply it by the conversion factor of the cob you are using. The reason there is a conversion factor is because cobs spectrum is tailored differently. What a 4000k Vero 29 puts out between 400–700 nm is different than a 4000k Cree CXB.
Figuring out conversion factors seems complex to me at this point but there are resources around that list our specific cobs conversion factors. It's basically µmol/J which is a conversion between energy based PAR and photon based PAR and it varies depending on your spectrum. From what I've seen the typical conversion factor of most white light cobs are between 4.50 and 4.70.
The 4000k Vero 29 has a conversion factor of 4.62 so if I take my PAR watts after subtracting losses and multiply it by 4.62 I get an approximate PPF.
example: 4 cobs@2100ma = 319.2w of dissipation.
319.2w/40% efficiency = 127.68 Par watts.
127.68 x 4.62 = 589.88 PPF
589.88 PPF - 10% losses = 530 PPF
In a 2x4 tent.
8sqft x 10.76 = 0.74m2
530PPF x 0.74m2 = 394µmols/sec/m2 or 394 PPFD
Those numbers aren't exact because I didn't look up the true efficiency of the Vero at 2100ma. This is my basic and limited understanding of it. Hopefully someone with more knowledge can expand on it....that is....if you want it to be expanded! It's almost as fun as peeing razor blades.
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