MrTwist1
Well-Known Member
I thought it was looking a little sparse - are you a defoliation convert? I'm still on the fence about it really. I want to do a side by side one day to find out for myself. What do u think about it?
Cunfusion looks nice
Another Cree CXB3590 DIY thread
- Thread starter captainmorgan
- Start date
Cunfusion looks nice
captainmorgan
Well-Known Member
I thought it was looking a little sparse - are you a defoliation convert? I'm still on the fence about it really. I want to do a side by side one day to find out for myself. What do u think about it?
Cunfusion looks nice
It depends on the strain how much to take but it's never a bad thing if done right at the right time. GG#4 is not bad, wide node spacing with fans that aren't overly large. Chaos and Cunfusion has been a must with closer nodes and very large fans.
MrTwist1
Well-Known Member
Yeah I hear you man... some plants literally need it because of their structure.
captainmorgan
Well-Known Member
Wanted to see what some added red might do for the 3500k 3590's so I took the panels out of a A51 RW-75, it's 25 watts of 630 nm. Day 29 of flower for this Gorilla Fuck.
Attachments
captainmorgan
Well-Known Member
Day 49 for this Gorilla Fuck, really packing it on.
Attachments
ttystikk
Well-Known Member
Fuck! What a gorilla!
captainmorgan
Well-Known Member
Yep, just turn them off to take pics.
bassman999
Well-Known Member
Looking nice Cap'n!
I have some S1s of GG4
I have some S1s of GG4
cyberbear
Member
The difference is the size of the cob, there are so many other variables in the numbers that follow CBX 3?90 that the question is barely valid. There are 36 volt and 72 volt COBs, there are 12,000 lumens and down, lumens vary with the temperature of the COB/emitter/led, temp. also has a lot to do with the life expectancy of the emmiter. As operating temp. reach 100 deg C, lumens drop. The maximum forward current is 1/2 the mA for 72V emitters as it is for 36 V. There is a whole series of CBX COBs, they top out with the 3590s that are one a 34.9mm substrate, ergo the 3590 3017s are on a 27.35mm substrate, there are different density COBs, all different sizes and wattages giving different lumens. Then there are the K value or degrees Kelvin. Each different K value has a different output curve in light wavelengths and the strength at each wavelength represented on a graph with a curved line. Most people prefer 3500K for plant growth, the higher the number the more blue light and the less red light. Red+growth, bluie+flowering. This is a grade school level explanation of the different Cree CX COBs that are available. CXA was the first generation, CXB the second. MC130p said " don't forget th\e datasheet explains everything" exactly. You need to choose which one you want in relation to the wavelengths of light and their corresponding strengths as well as the lumens per watt and as imp[ortantly the lumens per dollar as each one is priced differently. The COBs, or diode arrays are tested and put into categories as to how many lumens they produce at a certain temp., Voltage, and current. This forum is not really the place to get into how these diode arrays are made and why they are different brightnesses. the number of diodes should be of no real concern as they are not able to be accessed individually, and are being used for their light-emitting properties, not for things like circuits to change AC to DC, AKA, diode bridges, etc. CREE freely publishes all its product specs. and unless you are buying them in large amounts and have a wholesale license I believe you have to buy them from distributors like DIGI-Key or Mouser, etc. Cree LED arrays are generally the best made, longest lasting arrays of their kind, they are rarely the least expensive. LEDs do become less efficient over time. I was just browsing the web and came across this site as I was thinking of making a large grow area using light I made from raw emitters. It is easiest to just go on Amazon or elsewhere and buy the LEd arrays that are on a small rectangular aluminum plate and have a microcircuit that allows you to just plug them into the wall. They even have them where no soldering is needed. For those, I would either tin the leads or use solid wire to push them into the solderless connectors. I just got through putting 2X 50 watt COBs like that on an old 1/2" thick (total) finned copper heatsink from an old cooler used on a 6100 series AMD Opteron CPU. Cost me under $15 for the LEDs and I used an old wall-wart 12V power supply for the cooling fan with a $ 4-speed control for the fan. $20 and I have a full 100 watt (input) 3500K LED grow light. It's about the same brightness as a Canna Grow Cree CBX 3590 3,500K based, 10" round passively cooled grow light that cost $140. It has a lens so can be used in a more direct manner. The heatsink is about 3"x4". The one I made is not dimmable like the one I bought and the LEDs are from China I think, but it runs cool at a reasonably quiet fan speed, crank the fan and the copper never gets up to bathwater temperature. Make sure you use thermal grease when cooling LEDs. Well, I think I will go and check this site out a bit, I hope this answer proves to be of some help to someone. Growing under artificial light can be a challenge, but I find it a fun one. High output LEDs have made it MUCH more affordable and saved many beautiful Colas from being burned by metal halide and sodium-based lights. Happy Lighting...
cyberbear
Member
Those COBs can run at up to 1,800mA. Just wondering why run them at that low a current? Are you using 2 or 3 step COBs? I was also wondering about the size of your grow tent. Are those meters, yards, feet, the 3x3? I haven't grown in about 40 years, so forgive my ignorant questions, please. SO, I take it that screens and scrog are about growing through nets to spread the branches? Do you use only downlighting? I am going to get back into growing and the last book I read was Rosenthal's and someone's first addition, I assume there is a second by now, LOL. Maybe not? What is the latest popular medium to grow in, besides soil that is? I do understand quite a lot about LEDs as well as Physics, Electronics, Chemistry, Biology, etc. I am kind of a science geek type I guess. Well, That's what I went to school for also. So does everyone have a good photosensor to grow with these days? I noticed you mentioned PPFD. I have a decent one I made, could make a better one I suppose, do you measure all over or just at the upper grow surface? I had planned to light from top to bottom and not just downlight as artificial light sources lose so much intensity with every inch of distance I figured I would modulate the blue light to get the proper branch spacing and leave spacing etc. Does anyone grow from seeds still or mostly cuttings? If I don't have a good source of cuttings, would you be so kind as to recommend a reliable seed source? I have just started laying out my grow space using CAD. Any help would be greatly appreciated. I don't know my way around the site, I just joined a few hours ago. I do qualify for Medical Marijuana for chronic pain and am on Fed. Disability. I live in NYS and it is SO expensive here. That's why I decided to grow my own. I still have to decide exactly what strains to grow and if I am going to have to use a filter for the smell, or if I can just vent outside, have to check the state laws to see how careful I have to be. Sorry, I am rambling, too many questions. Thanks again for any help.
CyberBear
captainmorgan
Well-Known Member
Mine are the 36 v version that can handle up tp 3,600 ma and I drive them soft for higher efficiency, the tent was 3 foot square. I prefer vertical scrogging now.Those COBs can run at up to 1,800mA. Just wondering why run them at that low a current? Are you using 2 or 3 step COBs? I was also wondering about the size of your grow tent. Are those meters, yards, feet, the 3x3? I haven't grown in about 40 years, so forgive my ignorant questions, please. SO, I take it that screens and scrog are about growing through nets to spread the branches? Do you use only downlighting? I am going to get back into growing and the last book I read was Rosenthal's and someone's first addition, I assume there is a second by now, LOL. Maybe not? What is the latest popular medium to grow in, besides soil that is? I do understand quite a lot about LEDs as well as Physics, Electronics, Chemistry, Biology, etc. I am kind of a science geek type I guess. Well, That's what I went to school for also. So does everyone have a good photosensor to grow with these days? I noticed you mentioned PPFD. I have a decent one I made, could make a better one I suppose, do you measure all over or just at the upper grow surface? I had planned to light from top to bottom and not just downlight as artificial light sources lose so much intensity with every inch of distance I figured I would modulate the blue light to get the proper branch spacing and leave spacing etc. Does anyone grow from seeds still or mostly cuttings? If I don't have a good source of cuttings, would you be so kind as to recommend a reliable seed source? I have just started laying out my grow space using CAD. Any help would be greatly appreciated. I don't know my way around the site, I just joined a few hours ago. I do qualify for Medical Marijuana for chronic pain and am on Fed. Disability. I live in NYS and it is SO expensive here. That's why I decided to grow my own. I still have to decide exactly what strains to grow and if I am going to have to use a filter for the smell, or if I can just vent outside, have to check the state laws to see how careful I have to be. Sorry, I am rambling, too many questions. Thanks again for any help.
CyberBear
cyberbear
Member
Mia culpa, I didn't realize you had 36V-chips. I wanted to say I really like the people on here so far and the whole feel of the site. Could you explain verticle scrogging to me, please? Lowering the current will run the chips cooler which will increase efficiency, but it is a function of temperature and not current. If you were to run your chips at 2,400mA the difference in output between 85 deg C and 25 deg C is around 1,000 lumens at exactly the same current, temps would be those taken at the thermocouple attachment point on the substrate ( on the ceramic substrate chips at least). driver efficiency can also make a noticeable difference. I know more about and have worked much more with linear power supplies, which are not efficient unless they have a tracking down converter. I am not sure, but it would seem that one or two larger switching PSU/drivers would be more efficient than separates, not really sure about that though. I look forward to learning a lot here. Lots of knowledgeable people!
Rocket Soul
Well-Known Member
Thats not really true. For higher current each chip will run with higher voltage, which means the chip will use more power, even with a linear flux response.
captainmorgan
Well-Known Member
Vertical scrog with quantum boards.
cyberbear
Member
Well, as far as voltage increasing with current and diodes are what is in question, that would depend on the power supply/driver. Is it constant voltage, constant current, neither or both? I worked in the field and my database, which is published by Cree has slightly different numbers, there are also 2 step and 3 step chips and ceramic and aluminum substrate chips I believe. See attached for what Cree publishes, there is a lot more, but some take special programs to access, etc. I had to find it on my computer, I had been working from memory. Did you get your figures from Cree or another site? LEDs are kinda odd things in that even when Cree makes a run of chips they have to be tested and then sorted. my info may not be the very last published edition of the attached files. maybe a year old at most though.
I really like the vertical scrog idea, it doesn't reduce the growth rate by stressing the plants? Years ago I would hang lots of fluorescent lights in between the plants and line the edges of the grow room with them. Some cool white, some warm, some the purplish grow variety. I think I am going to start off simple and small now though. Do you have the net hold up the weight of the Colas/buds? Stems seem kinda thin. Nice pic though
.
I really like the vertical scrog idea, it doesn't reduce the growth rate by stressing the plants? Years ago I would hang lots of fluorescent lights in between the plants and line the edges of the grow room with them. Some cool white, some warm, some the purplish grow variety. I think I am going to start off simple and small now though. Do you have the net hold up the weight of the Colas/buds? Stems seem kinda thin. Nice pic though
.
Rocket Soul
Well-Known Member
Pic below is from the cree datasheet, voltage rises with current which means more power consumption. Its a bit tricky, cause when you look at the graph of flux versus current it tends to be very straight and does give the impression that light output is linear proportion to current but this would not take the voltage increase into account. Efficiency (light/w) usually increase with about 10% every time you half the power.Well, as far as voltage increasing with current and diodes are what is in question, that would depend on the power supply/driver. Is it constant voltage, constant current, neither or both? I worked in the field and my database, which is published by Cree has slightly different numbers, there are also 2 step and 3 step chips and ceramic and aluminum substrate chips I believe. See attached for what Cree publishes, there is a lot more, but some take special programs to access, etc. I had to find it on my computer, I had been working from memory. Did you get your figures from Cree or another site? LEDs are kinda odd things in that even when Cree makes a run of chips they have to be tested and then sorted. my info may not be the very last published edition of the attached files. maybe a year old at most though.
I really like the vertical scrog idea, it doesn't reduce the growth rate by stressing the plants? Years ago I would hang lots of fluorescent lights in between the plants and line the edges of the grow room with them. Some cool white, some warm, some the purplish grow variety. I think I am going to start off simple and small now though. Do you have the net hold up the weight of the Colas/buds? Stems seem kinda thin. Nice pic though
Of course temps also play into efficiency but its not the whole story.
captainmorgan
Well-Known Member
Those numbers were calculated by one of the guys here on RIU when the 3590's first came out, I remember later someone said they were slightly off. I veg normally then set the plant in the frame and weave the string into the plant and prune, that pic was probably day 1 of flower. I have a bad back so switching to vertical scrog made things so much quicker and easier to work on.
cyberbear
Member
I see what you mean, I think we were just looking at it in different ways. LEDs will degrade at much faster rates when hot, or overheated, there by reducing efficiency. I was looking at the LEDs efficiency more over time rather than instantaneously. If an LED is kept cool it will put out more lm/hrs of light in it's lifetime partially due to the fact that high temperatures degrade an LEDs ability to produce light. If the temperature is high enough, that period of time can be rather short. An LED will not put out more lumens per watt of power when it's current is reduced as far as I know, at least as a function of time, bit I could very well be remembering that part of Physics incorrectly. The minimum flux output of a given LED with a constant current and a constant voltage applied to it will be greater at a lower temperature. The values stayed by Cree about this are calculated and for reference purposes. You are very correct that an LEDs efficiency has to do with more than just temperature, or current. You are correct about this and I incorrect, please accept my appologies. Heat is an LEDs or pretty much any semiconductors enemy when it comes to life span as well as efficiency, especially over time. Transistors have the same issues with heat. I should have read up on what I said before saying it and eliminated my confusing the issie.. I often don't realize how much I have forgotten in the time since I learned all of this in Physics class, my memories are not quite as crisp and clear as when I was younger. I will try not to post any definitive statements without checking them first. Thank you for handling my error in making an incomplete, incorrect statement with such kindness and tact. I am finding that now that I am no longer working in the science field, I am forgetting things I never thought I would forget, I could just be getting old. My Dad always says that the more you know, the more you have to forget when he remembers things incorrectly. When looking for those PDFs, I realized how many TBs of stuff like that I have that I should just delete. I was sort of surprised I found it! Hope some of it was new information for you. If you ever want more information like that, I have lots.
Peace,
Brian
"CyberBear"
Peace,
Brian
"CyberBear"
cyberbear
Member
e LEDs are not strictly linear in terms of this behavior. Higher per-strip drive levels promote higher operating temperatures, which depending on the scenarios one chooses to compare can cause reductions in efficacy on the order of 5 to 20%.
tilopa108
2
May '20
Question about nominal drive current.
rick_1976
Applications Engineer
May '20
“Nominal” drive current values typically indicate the level at which the other device characteristics are measured and communicated. Manufacturers generally choose this value to reflect an operating point that offers a good balance of competing design tradeoffs under expected operating conditions.
Because different applications value different performance characteristics differently, it’s not necessarily the optimum drive level for all purposes; it’s a suggested starting point. Yes, further reductions in drive level may yield increases in luminous efficacy, but there is a point of diminishing returns.
tilopa108
1
May '20
Sorry, I totally changes the focus of my quesiton, or really added a question by editing my post completely, but you had already responded. I should have just left it and added question. That was dumb.
Thanks for clarifying about nominal current.
Just to be clear about efficiency. As I am about to buy a driver and trying to decide between 2 different ones.
So, 2 scenarios:
1: total wattage is 400w, current is 1000mA per strip for a total of 10 strips. Voltage is 40v.
2: total wattage is 400w, current is 750mA per strip for a total of 10 strips. Voltage is 53.3v.
Scenario 2 would be more efficient? In other words efficiency comes from lower drive current even if the voltage increases?
David_1528
Applications Engineer
May '20
Your scenarios don’t make sense, if you are using the same LED strip for both scenarios. The higher the current passing through a strip, the higher the voltage drop across them. Here is how I would try to explain how efficacy works:
Say you run 1000mA through 10 LED strips at a Vf of 40V, and it yields a total of 70,000 Lumens. This would give you an efficacy of 70,000 Lumens / 400W, or 175 Lumens/W. If you ran 500mA through the same LED strips in the same arrangement, the Vf would probably be in the neighborhood of 38.5V, and the output would be roughly 36,000 Lumens (possibly slightly more). Under this scenario, your input power is 38.5V x 5000 mA = 192.5W, and your efficacy is 36,000 Lumens / 192.5W = 187 Lumens/W.
So, your efficacy increases from 175 Lumens/W to 187 Lumens/W, but you are getting barely over 1/2 half as much total light. If you put 20 LED strips in parallel and ran them all at 500mA, you would get about 72,000 Lumens at 385W (20 strips x 0.500A x 38.5V). This would give you more light with less power, but you would use 2x the number of LED strips to accomplish it.
Does that make sense?
tilopa108
May '20
Yes, it makes sense. And it opened up a greater understanding. I should be focusing on lumen output instead of wattage. I was not remembering that wattage does not simply translate to amount of light.
I’m using these 2ft srtrips: https://www.bridgelux.com/sites/default/files/resource_media/DS132 Bridgelux EB Series Gen3 Data Sheet 20190617 Rev A.pdf 5
Which have a typical forward voltage of 19.1Vf and a nominal current of 700mA. And a typical flux @ 25c of 2490 lumens. And efficiency: 19.1*.700 = 13.37w = 2490/13.37 = 186 lm/w.
Now, if I want to find the lumens and wattage of an array of these strips driven by a particular driver how do I do that?
10 of these strips using this driver: meanwell HLG-240H-48 https://www.meanwell.com/Upload/PDF/HLG-240H/HLG-240H-SPEC.PDF 3
This driver has total current of 5A, and a voltage range of 24-48v. I would like to wire these 10 by wiring 2 in series 5 times, then taking those 5 sets of 2 and parallel them together.
I can find the current per each of the 5 sets by dividing the driver current by 5. which is 5A/5 = 1A. Using the datasheets “current vs forward voltage” graph I can see that at 1 amp the voltage is about 19.6v. If I double the voltage: 19.6v * 2 = 39.2v. Each series pair uses 39.2v * 1A = 39.2w, multiply this by 5 = 39.2 * 5 = 196w. And the number of lumens is simply 10 * 2490 = 24900. So efficiency is: 24900/196 = 127 lm/w.
Clearly my calculations are incorrect. What am I doing wrong?
David_1528
Applications Engineer
May '20
What you are missing is the increased lumen output from the increased current. That is given in the Figure 4 graph.
image
The lumen output will be about 140% of what it is at the test current (700mA), so roughly 3486 lumens per strip. Ten of these will give about 34,860 lumens for an efficacy of 34,860lm / 196w = 178lm/w.
In a real application, this won’t quite be true, because light output and Vf both drop slightly at elevated temperatures for a given current (which will be the case here due to self heating). The Vf drop adds slightly to efficiency, but the loss in light output more than makes up for that, so overall efficacy is reduced by about 3.5% percent if the case temperature rises to 60°C. This comes from Figures 7 and 8 on page 7 of the datasheet.
I found this using " Hey Google" on my phone...