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It would be more than that. I have Vero10's which have 18 dies of 1W (35 mil) in a 2x9 configuration. The forward voltage per die is about 3V. Extrapolating the voltage and current, the Vero18 would have 80 1W dies. The Chinese would call it a 80W COB.

Interesting to note from the first curve (below) is that the light saturation point increases with more blue light. So the higher the irradiance, the more beneficial blue light becomes.

The drivers are from Satisled, there are some 350mA/120V and some 450mA/80V. I will start some thread later about building with the Vero 10's. You can multiply the watt/m2 figure by 5 to get an estimate for the umols (for a normal balanced spectrum). In your case it would be about 600 umol/m2/s.

It's great to see your switchboard - I have been working on one too for the last few days. I should have mounted the drivers vertical like you did for better air convection.

Chaz, I was talking not about the optimum but about the absolute efficiency of a plant. This is very low, like one photon in a hundred is utilized in photosynthesis and the rest is wasted. Of all plants sugar cane does photosynthesis the best, turning 8% of light energy into sugar. You seem...

Most often used for this is the McCree 1972 action spectrum; the raw data is in the text file. Note that this shows the relative efficiency. The absolute efficiency of plants is very low, in the order of 1%.

For COBs the specs tend to use the case temperature Tc (measured at the back of the heatspreader) instead of the junction temperature Tj. There is no need anymore to estimate the Tj or even to know the junction to case thermal resistance.

That driver is very dangerous with its 285 volt, I hope you will use something else.

600W of pure light would be equivalent to for example 12 of the new A51 panels, to give some idea of the magnitude.

Hello & welcome, To summarize the approach, the idea is to have the same amount of red and blue light that the sun has in outer space, plus 25%. That is way way way too much power. The plants would nearly incinerate. A good target for the amount of light is 800 umol. Higher than this and...

It's 3.7 degrees total; This is the temperature difference between the back of the Vero and the face of the heatsink. The equation used is not so scary at all, it's called Fourier's law. That totally depends on the heatsink and its environment, but it's not different from using single...

Don't forget that a COB has a large contact area, which makes for very effective cooling. To take a worst case scenario: Emitter: Vero 13, area A, diameter D = 36mm, Q = 30W heat (that is a overdriven vero) Glue: k = 0.5 W/m/K (that is a shitty conductor) Gap: dx = 0.25mm (that is a wide gap)...

What you are finding is a real effect. Temp goes up, Vf goes down, current and hence number of light quanta remains the same. The same 'output' for less power, right? In terms of quantum flux: yes but in terms of power: no. While the number of photons stays the same, the average energy per...

Yeah I understand, it's no fun waiting for digikey. You will have a very beautiful light but at the price of somewhat less efficiency.

That is a two component silicone glue, it is a bit messy to mix and not intended for heatsinking. From the same brand here is a better deal. This is the sort of goo that the Chinese use to glue small LED bulbs to 20mm stars.

There is no need for drilling and screwing, the Arctic epoxy bond is extremely strong by itself. Another option is silicon glue, it's still strong enough but offers a chance to remove the the parts from the heatsink should the desire ever arise. I like everything about the project except the...

Hi muumi, glad you like the thread. I haven't noticed any efficiency differences across the various CXA sizes. From the specs I looked at it was always around 139 lm/W at test current. Haven't looked through all the individual specs though. At half the test current it would indeed be about 170...

SDS, how about playing a game. I post a spectrum and you tell whether it's a blend of warm and cold or if it's a neutral...

Well spectrum-wise there is not much difference between mixing warm and cool white or just using a single neutral white.

Congrats on your vero's arriving. I think Digikey has better shipping rates worldwide. Testing with the batteries should be safe. A 100% safe way is to attach a voltmeter and shine a bright light on the Vero. The Vero is then used 'in reverse' (like a solar cell) and should generate some voltage.