PICOGRAV
Well-Known Member
When you look at these data sheets, yes it can get confusing and everyone seems to show ratings in a different way. 3.1 amps is around the highest you would want to drive the vero 29 with standard cooling. Going well below 25C junction temperatures possibly would allow you to go higher and higher with your amperage but then the cost of cooling starts to be impractical.One thing I don't like about the Lux's is how they rate their efficiency per watt. @3.1a [don't have the datasheet in front of me] but don't they list them down around 100-105/lu-w? and their intensity is crazy at that current.
Should lumen efficiency count as just a baseline to compare other models? Does it appear slightly dimmer at that higher current? Is that all that is meant by "lumens per watt efficiency"?
I think the 3 and 4k together make a veg and bloom light. I mulled it over for hours last night. The 5k seems a little too blue around 400-450nm.
There are also some threads out there on Peltier's and LED cooling. For me the biggest drawback for them is their high power usage, but they are cheap as hell, as big as you would need for these COB's, but the smallest use 50-75 watts. But at quick retail they are $5.
.....article too somewheres about DARPA [fuckheads] using thermoplastic heatsinks with blowers to increase LED efficiency. It's out there.....so there are thermoplastic heatsink designs out there as well.
I think water cooling has its place, especially for high power growing in enclosed spaces. No doubt about it. The water blocks seem to be made for COB's and I don't think its that complicated to form up an enclosure to keep water away from electro and vice versa.
Then there are those heatsinks with the little air pump built right into the sink itself [Sold at Futurelighting solutions?]
Bridgelux has a different approach with how they rated these arrays, they class them in available lumens and most of the vero 29s can give you over 10,000 if needed.
"Does it appear slightly dimmer at that higher current?" No, they will always be getting brighter the more current you pass through them, its just at one point they peak at a certain luman per watt, and will continue to get brighter but at less efficiency, so more of the power you add is turning into heat rather then DC Flux or lumen (Electromagnetic radiation), this is how we figure how much power is getting applied to the plant or grow area. A lot of people will say you should use PAR ratings but I still think lumen is a better measurement for our applications. Light has never actually been proven to be "Photons" and calculations from Electromagnetic radiation to Photon counts are unbelievably complex and don't really make all that sense. Light radiation has different adsorptions at different wave lengths, blue light can pass though more plant matter before the waves finally combine with the photo-reactive plant matter, red waves are larger and wont bounce around as much and cover the photo-reactive molecules more like a blanket (less penetration).
When people talk about Photons they see it as these tiny tiny particles are traveling from the light source into the plant. They believe that you can count them and then take a rating on how many you are getting per meter squared per second. This general way of calculating Photons this dose not factor in the different absorption rates of varying wave lengths of light and how say, the blue light will bounce around and change a little before is absorbed or reflected away compared to red light that is, in a way bigger and needs a different sized partial to react fully with.
I agree that the 5000K is too blue to flower on, but I still believe the 2700Ks should be the base or the bulk of the light you are throwing down. In the data sheets there are guides to actually calculate the heat these arrays will produce in watts but for an example if you running the 5000K at 100 watts about 78-85% of that would be heat you need to move away from the LED array, so a 100 watt heatsink would be OK.
Futurelighting solutions (http://www.futurelightingsolutions.com/) is a great resource and they are a Bridgelux suppler now and can supply products from a lot of the Bridgelux partners as well but you mostly have to buy in boxes or cases, so 10s or 100s of LEDs or heatsinks at a time. For a manufacture yes but DIYer like us I would still recommend http://www.newark.com/, you can buy as small as you want to.