COB question

Ringsixty

Well-Known Member
Very much of a Noob when it comes to LED lighting.

My question is for anyone who really has the know for these things.
From what I have read. 1w, 2w, 3w 5 w etc LED config. don't not use the advertise power rating. It's less.
Is it the same for COB LED as well?
 

lax123

Well-Known Member
W= V x A so just multiply Forward voltage with amps consumption for a specific led and u know the answer to that question. looking at some random cobs it seems to me that they are more "truthfull" about wattage
 

PICOGRAV

Well-Known Member
but that depends more on the integrated constant current source, not the cob itself, doesnt it
You will also have to look into the Power Factor of your driving or supply circuit. You should always use Power Factor corrected PSUs or you will be using more current for the same amount of watts, which equals more power in general and electricity company's don't forget about this...
 

FranJan

Well-Known Member
Do you Guys think COBs will be where the LED grow light industry goes?
If you want my opinion O60, not really. COBs are an evolution in LED lighting and there's probably something in a lab somewhere ready to be the next big thing. COBs are part of a solution for a grower and IMO are not ready for flowering by themselves, though they make great side lighting because of their thin footprint. Plus they are are susceptible to heat effecting their output and are probably best for the veg/clone room. Plus no one is making COBs, (not to be confused with SMD arrays), specifically for growing cannabis. Yet
. But ultimately COBs will get better for growing with more efficient die and better cooling.

Having said all that PICOGRAV is off to a good start with some Bridgelux COBs. His setup is pretty off the hook but proof for me will be coming soon when he flips.
 

Bumping Spheda

Well-Known Member
COB's and multichips don't have primary optics. Their viewing angles are ginormous. A potential benefit to the Cree lights on eBay that have like 10 in series. The Cree chips have 120 degree viewing angles (which is still large, but not 180 degrees).

From what I've seen, most COB's and multichips are driven to "maximum." When they say 50W they usually mean 50W at the wall. If you're supplying your own driver, though, it could be whatever you want it to be, really.
 

Abiqua

Well-Known Member
COB's are an "evolution", I like that.


[Sweet, there are reflectors at least, for the Bridegelux BXRA series. Bad mofo's, but steep angles as much as 14 degrees symbol. ]


This area has room to grow, watt for watt they are becoming fairly efficient.

Datasheets need to be consulted for specific current but lax is right about amount of current controlling your output wattage, not at the wall necessarily. [fans, other circuitry and such]

For example: I have been looking at all of the Bridgelux Vero's, they are 120degrees as well!

The Bridgelux Vero 10 according to Digikey, had a test current @350mA @27.1v [=9.56w] and its Max Current is 700mA [=18.97w] and it will run 13.6w@500mA [datasheet says [email protected]'s] and over 20w's at Max Current. According to the datasheet, the lumen output is increased with current above 350mA, but the effficiency looks like at will drop off at least 20% as you push that much current.

I thought as you push COB's or any LED for that matter to the max, that the color spectrum changes? Hence why the color ratings for WW for instance, range from 27-33k?


I like this one from the random Reef guys, the Lumia 5 channel 100w Multichip. Putting it together will cost a small fortune but I see this being another "evolution" of multichips. They won't go away entirely [within 6 months] but they will change a bit, better die, better spectrum, more efficient diode's, new customizations.

Optics seem to be one of the trouble areas, I have seen some crazy optics out there, but there are some reflectors at Digikey?
 

lax123

Well-Known Member
i think a big disadvantage might be, that i think, for growing you would prefer coverage over a "spot" that pumps out like 100W. Imo its much more efficient to use 10x 10W instead.
 

PICOGRAV

Well-Known Member
i think a big disadvantage might be, that i think, for growing you would prefer coverage over a "spot" that pumps out like 100W. Imo its much more efficient to use 10x 10W instead.
When you are seeking Efficiency, larger chips will always trump mutable smaller ones, Sharp is now going to produce chips rated at about 100W and 143l/w, far better then most 10 watts available, you should have a look at my grow, I am using 10,000 lumen chips, they are rated at about 80-130 watt depending on how high you want to drive them and they are in the new realm of lumen per watt, well over 100 L/W, close to the 140 mark.
 

lax123

Well-Known Member
When you are seeking Efficiency, larger chips will always trump mutable smaller ones
hmm i didnt really look into this but i thought it is the other way around. As any chip driven at lower current is usually more efficient. With "efficient" previously i was not talking about electric Efficiency or specifically about 10W, but about 100W beeing split into smaller Chips is better for plant coverage, so more efficient for growing imo. Looked at your grow, it looks fantastic also considering how cheap you got them -perfect -ok fak coverage just get some way cheaper high watters. About your vero i read they r fakers with their 120 lm/W because every serious led Producer gives their data at real chip temps like 85°C and not on some super low 25°C or can you run ur Chips with inner temperature at 25°C?
 

PICOGRAV

Well-Known Member
hmm i didnt really look into this but i thought it is the other way around. As any chip driven at lower current is usually more efficient. With "efficient" previously i was not talking about electric Efficiency or specifically about 10W, but about 100W beeing split into smaller Chips is better for plant coverage, so more efficient for growing imo. Looked at your grow, it looks fantastic also considering how cheap you got them -ok fak coverage just get some way cheaper high watters. About your vero i read they r fakers with their 120 lm/W because every serious led Producer gives their data at real chip temps and not on some super low 25°C or can you run ur Chips with inner temperature at 25°C?
When you are looking at distribution power, any sort of power for that matter, you have to deal with loses in interconnect. I know it might not seem like much but using or having LED diodes millimeters apart opposed to inches or even feet would save a lot of wasted power. We are working with DC low voltage power which is very easily lost in interconnect cables. Just this factor alone should sway your thinking from the smaller chips to larger ones.

I don't think you have read or understood the technical information Bridgelux offer on there chips. LEDs like this have a huge range of operating parameters and are effected be lots of different factors;

http://www.bridgelux.com/assets/products_portfolio/DS33 Bridgelux Vero 29 Datasheet 2013.07.18.pdf

Look at, Table 2: Selection Guide, Stabilized DC Performance (Tc = 85°C) - you are still going to be with in 100-120 on most of the models.

Have a better look at the information provided and if you want to ask questions about any other measurements just post them.
With the cooling I have the backs of the chip, the metal plate would be around 45°C maximum, it wouldn't be ridiculously difficult to achieve constant 25°C if careful and well planned cooling systems where in place.
 

lax123

Well-Known Member
When you are looking at distribution power, any sort of power for that matter, you have to deal with loses in interconnect.
interesting Point, do you have some values there for some examples or else. I mean i could start calculating stuff but if u got some numbers... but it makes me wonder without looking deeply into it, on my DIY Panel with about 170W, Excel calc of Vf and A pretty much equals what i measured with a DMM and there r more than 80 leds connected with wires
I don't think you have read or understood the technical information Bridgelux offer on there Chips.
i havent read that, i just gathered info from an "led News page", stating that vero Marketing is a lil bit.....looking at table 2 there is only one reaching that 120lm/W and if they sell like all of them >120lm/W in advertisments or something like that well then they lied Kind of. idk more, maybe i still got it wrong, just what i read there: "vero saying 120lm/W @ 25°C while others give their values for 85°C..." also highest lm/W only one reaching 120lm/W is the coldest White, but idk how that then compares to high end WW of Osram or cree because for WW there it gets to 80-110lm/W
 

PICOGRAV

Well-Known Member
Could you tell me a little more about the design of your panel? How you are supplying the power? Drivers? PSU? Measuring power can be a little tricky some times, Watts as in volts times amps is not the same say as VA, Volt Amps, power companies charge you based on a more true rating of the actual power being used. Like I said before using Power Supply's with corrected power factors or going to to give you a slightly better performance when you look at cents per lumen, weather this makes up for the added expense or time to design a more correct circuit is up to you.

When I set out to pick the LEDs I wanted to use for growing I had no brand concepts in mind, this seems to be where most of the biasing is on these forums, I took what I knew about power and electricity, looking into lumens, lux, color temp, CRI and various other factors. Bridgelux released the Vero 29 as a 10,000 lumen chip, not a 120 l/w or 130 watt chip but a chip or package that can almost guarantee you will be able to produce the 10,000 lumens under any normal operation parameters, weather is 25 C or 85 C, we all know every application is going to be different and that's how they are designed. If you could guarantee to me that you would not let the chips get over 25 C and that you only wanted 5000K light then yea I would say, you will get about 140 l/w but that's not what you are saying. If you want chips that are always going to be able, one way or another give you 10,000 lumen then these are the ones but I challenge you to find a higher rated chip, if you hold high value in efficiency and have needs for high power, these are the ones, no joke there is nothing you can buy that will out preform these Bridgelux chips on the market right now.
 

lax123

Well-Known Member
i smoked some so i hope i get this right.
Could you tell me a little more about the design of your Panel?
i have 4 Clusters, (adding up, seedling/veg, pre flower, flower, according to numbers Stardustailor provided somewhere), each driven by a Driver 650mA. Datasheet Vf was for 700mA. For 700mA Vf should have been for all leds in that e.g. Cluster 69V while i measured 67V. A was about 655mA, so naturally Vf is lower and of course there is a tolerance for each led. According to what you said i would have expected a much higher voltage loss by wire.
Watts as in volts times amps is not the same say as VA, Volt Amps
im not english, sry i dont get what u r saying there. What do you think about equally spreading light vs 1 hotspot, dont you think that would be much better? I mean 10K lm is nice, but from one small single source, isnt that like one of the disadvantages of hps and so on?
 

PICOGRAV

Well-Known Member
In my opinion Stardustailor needs to approach things a different way, I challenged the theory behind his findings and have not heard back yet, I am aware that his first language is not English and you yourself might connect with what he is saying. I would love to explore the ideas that he has but if people are un-willing to communicate even on basic levels then that is impossible.

What are your goals with the panel? You are wanting to have even displacement of the light over a given amount of space yes? Firstly the losses I am talking about are very very small but can add up to large amounts when you are calculating dollars and cents of electricity used over a 90 day period. The best measurements would be taken form your 220 volt supply line and start calculations from there, that will give you total power used and what you will be charged for.

lets do an example, lets say you are averaging 1 amp of current at 10 volts to get 1000 lumens which will give you a certain amount of growth. About 10 watts of power, charged at 10 cents a kilo watt hour. You will have to run this little light for a hundred hours to use 10 cents of power, bare in mind this is resistive load we are talking about and with a power factor of 1. So blasting this little light for 18 hours a day over 90 days you are looking at about $16.20, pretty cheap? Lets say if you used smaller wires that are more resistive to the flow of electrons and you require now, 10.5 volts at 1 amp to produce the 1000 lumens, this will work out to be $17.01 in power used, next you have to look at power factor and then multiplying the system power and cost to scale it up to what you are going to be working with in the end. Like I said before the loses could be small but add up over time.

I think the biggest example of a hotspot is the sun. I don't know why no one has brought it up before but as even as you can make a canopy light panel, you are still only hitting the plant from one angle. If you reflect a single hotspot around the plant you will be getting light at high intensity in spots you could never reach from above. You could also do this with an array if tiny little lights set up around the plant but that would be quite complex to pull off. I use the two LEDs above and rely on the reflections to diffuse the light at almost every angle around the plant, to achieve very high ambient light levels, saturating everything in light just like outside. I have observed some unique leaf movement that I am not sure, if its connect to this style or type of lighting or just something I don't understand about the plants yet.

HPS is a very good light system but has a few little downfalls when you use for growing, yes they are almost the most efficient lighting you can have but they produce light pretty much at 360 degrees, its hard to reflect it all back to the plant with out dealing with great power losses, unless you setup vertically growing you will also have to deal with this.Then the heat problem, LEDs at the same rated power could be producing more heat then a HPS light but it is almost all on the opposite side from which the light is emitted. This give you a great way to ride of the heat and stops it from going into the plants. HPS light intensity would also drop off a lot more then LED as you move away from them.
 

FranJan

Well-Known Member
"When you are seeking Efficiency, larger chips will always trump mutable smaller ones"
Hey Pico can you explain this a bit more. This article illustrates what I've been led to believe about LED efficiency.

http://www.myhydroponicgardening.com/the-cannabis-growers-guide-to-led-grow-lights-1w-versus-3w-and-higher/


"To be more clear: a 3W LED is not 3x as bright, powerful, or intense as a 1W LED. Expanding upon this, we can reach the conclusion that three individual 1W LEDs will be brighter, more powerful, and more intense than a single 3W LED and the reason comes down to efficiency."

And SDS is a bit of a thief and charlatan. He takes a bit of info from this study, then takes what he wants from that study and then just shoots something out of his ass. At best he's a cannapatalist who wants the people here to do his research. The man's got skills but he also has major issues and you shouldn't take what he says seriously. It's like he wants to be Kanna or something but not actually take the time to see if his theories work. Not a good member of the community but his DIY skills are second to none. Actually they're second to Guod's :). But I'm a little biased towards him cause of all the bullshit he peddled at one time and his constant disrespect for people. I remember one time I explained somehing to him and he just turned around and said the same thing back to me in a different way and then pretended he knew it all along. Fuckin weird, I've tried to stay away from him since. Personally I hope he never comes back here, just like in some post he started and said "goodbye" to all of us. Then he came back anyway. Beware.
 
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