I would like to build a few LED lights for my first grow in a couple of months. I have searched this forum for tutorials and builds, but all of them assume that idiots like myself have a general understanding of LED lights and electrical engineering, which I don't. I've also searched around google and youtube, and the problem is that all of the tutorials I've found are outdated. None of them even mentioned COBs. <br style="line-height: 22.3999996185303px;">My hope is that this thread will be a place where novices like myself can absorb information and methodology from more experienced light builders. I really appreciate the communal vibe of these forums. The goal is to be able to build my own light with your help and understanding, and then create a detailed how-to thread here at GC of the build I choose and construct, if and when I learn enough to undergo such a task. Perhaps as this thread unfolds, the how-to thread will end up being redundant, only time will tell. I want to stress that my biggest lack of knowledge pertains to how the system is built and how it works. That was another issue with the other tutorials I found. They all just listed the parts and said "wire it together". They weren't comprehensive nor detailed enough for me to absorb the process and information. I'll start off by explaining what I know so far. This is for the purpose of the pros letting me know where my understanding is flawed and what information I'm missing, etc. <br style="line-height: 22.3999996185303px;"><br style="line-height: 22.3999996185303px;">Diodes - This is just another word for 'bulb' to me. These are the little bulbs that make the LED light up. I don't understand what they're wired to or how they're wired regarding parallel vs series, or the difference between parallel and series wiring. <br style="line-height: 22.3999996185303px;"><br style="line-height: 22.3999996185303px;">COBs - Stands for Chip-On-Board. My lackluster understanding is that they're more powerful and efficient than the older diodes, but that's as far as that goes.<br style="line-height: 22.3999996185303px;"><br style="line-height: 22.3999996185303px;">Drivers - These are the middle-man between the diodes/COBs and the electrical socket that you'll be plugging your light into. They power the diodes/COBs. I don't understand how they're wired, nor do I understand the specifics regarding their voltage, wattage, amp draw, how many diodes per driver, etc. <br style="line-height: 22.3999996185303px;"><br style="line-height: 22.3999996185303px;">Fan - The fans are used to cool the unit. Whether they're used to cool just the diodes/cobs, just the drivers, or both, I don't know. I also don't know if they're wired to the drivers or if they are plugged in separately. So far, it seems that most people are using PC fans, which makes sense given their small size and low noise levels.<br style="line-height: 22.3999996185303px;"><br style="line-height: 22.3999996185303px;">Wiring - This is simply electrical wiring, which for those of you that don't know, is just an electrically conductive (allows electricity to pass back and fourth) wire (or wires) wrapped in a non-conductive material such as rubber. I don't know if there are different kinds of wiring, and if so, which type we are supposed to use for building an LED fixture.<br style="line-height: 22.3999996185303px;"><br style="line-height: 22.3999996185303px;">Housing - Housing is just the metal sheet that holds the whole unit together. Without it, you would just have a Christmas-lights-style octopus mess of lights. <br style="line-height: 22.3999996185303px;"><br style="line-height: 22.3999996185303px;">That's about it. There's clearly alot missing, including the process of putting it all together, which is why I've created this thread. I would love to hear from those of you who have built your own lights and those of you who simply have a good understanding of electrical engineering. How do you put it all together? What specs are we looking for in regards to drivers, COBs, etc? What's going on with the wiring (parallel, series, etc.)? What are the risks of doing it wrong, and how can we prevent that? Thank you ahead of time for your patience and for sharing any of your insights.
The hardest part for me to understand was a bit like you, how they need to be wired with the drivers and choosing the correct drivers. First we have to remember a few basic laws in electronics... First is that when you plug stuff in series it splits the Voltage and when you plug them in parallel they split the amps. So this means if you have 2x LEDs that requires 10V and 1000mA each. In series the will need 20V and 1000mA to run. In parallel they will need 10V and 2000mA. The other ''law'' was particularly tricky for me to understand because unlike most appliances like a cpu fan or razor or whatever, LEDs require to be driven with constant current and variable voltage. Usually a power supply that we use to drive cpu fans and other small appliances have a constant voltage and variable current meaning they give a determined voltage to the appliance and the appliance takes whatever currents (amps) it needs as long as it doesn't exceed the max rated power of the driver. With COBs, it is the opposite, you give them a determined current and it takes whatever voltage it needs depending on how hard they are run and how hot they are. This is why, when shopping for drivers, you will see them giving a voltage range like 20V-36V and a fixed current like 1.5A, this means the driver will be able to give a reliable 1.5A when the LED requires between 20V and 36V. Because COBs' Voltage will vary with current and temperature, it is not recommended to wire LEDs in parallel. The problem is that a driver can only supply one voltage at a time, not multiple different voltages. So if one COB is running at a different temperature than the other his voltage requirements will be different than the other COB and the power supply can only supply one voltage at a time and you may have some flickering or simply COBs that won't work. So in Series the voltage requirements are added up to a single voltage that the driver will need to supply, so the LEDs can vary Voltage all they want without affecting the circuit. All the info relating to Voltage vs Current can be found in their data sheets on website and you have all the info you need to choose a matching Driver. Basically you need to choose a driver that will supply the current (amps) you want and that will have a voltage a bit higher (but still in the range) that the LED needs. For example, Vero 18s require a voltage of about 30.2V when run at 1.4A and it increases to 31.6V at 2.1A. So I shopped for drivers and found one that supplies 15V-34V and 1.5A which is perfect because I know that my LED will be in the 30.2V range at that current. Wattage is measured by multiplying Amps and Voltage so 30.2V x 1.5A = 45.3W, so I will be running my LED at 45.3W. For the fans, I bought some CPU heatsinks that can handle 70W of cooling and I will wire them with a spare laptop power supply. Since my power supply is 18.5V and can handle 3.25A, I will have to spit the Voltage because the CPU fans are 12V, I could run them at 18V but they will be running to fast and will ruin their bearings in a couple of months... So I will wire them in sets of two in series until I reach 3A, this means each fan will be running at 9V which is fast enough to cool down my 45 Watts of power and will not wear down the bearings.
You my man, Gave me food for thought. Thank you. Ive been looking at the vero 29's or 18's myself. Issue im having is the 29s i can only seem to get at 3500k, i want 4000's. my other issue thats been holding me back, was this, You pretty much sorted it for me Thank you VERY much for clarifiying some hazy things I feel confident in following through with my own LED panel myself now EDIT by that I mean the how they are run. I can work out what driver I need now
I was looking at vero29s at first but after building myself a few spreadsheets to compare the 29s and 18s, I figured that my loss in efficiency with the 18s is pretty much gained back in price, mostly because I have a hard time finding a cheap driver that will do more than 40V and the price of the vero29 is more than double the 18. Once you understand how to hook them up, building them becomes childsplay! Edit: I can share my spreadsheets if anyone wants to
Ok so math/example time to help me think out loud. In yourexample COB, it needed 10V and 1,000mA. Say I wanted a light that powered 9of these. I guess I could find a stronger driver, but lets say the plan would be to wire them in groups of three, meaning I wouldneed a driver that could output 30V and 1,000mA, or one Amp. <o> </o> http://distributor.meanwellusa.com/webnet_usa/sear... If you scroll down to LED > CLG Series > and click on CLG 150, it'll open a data sheet. Don't know why I can't link that data sheet, but it's not letting me right now lol. Looking at this data sheet, I would go with the CLG 150-36.Assuming I'm supposed to be looking at the output in that data sheet, they provide36V and over 4k mA, so they'd be good to go right? This means I would buy 3 ofthese drivers and wire 3 example COBs per driver. <o> </o> Regarding the wiring in series, this would simply mean towire + to - on the COBs correct? So the wiring would be <o> </o> Driver > -COB+ > -COB+ > -COB+ <o> </o> And it would just end at the last COB? What about that last COB +? <o> </o> Regarding the PM you sent me, I'll share it here if youdon't mind so that I don't butcher it trying to type it myself. Ok still trying to wrap my head around this. I'll look at CREE CXB 3590 - http://www.cree.com/LED-Components-and-Modules/Pro... So to my understanding, COBs are supposed to have a fixed current that they require, and the voltage is variable. However, in the CREE sheet, it seems like there is two suggested voltage settings, and the current would depend upon the voltage instead of the other way around. Still trying to understand the COB spec sheets.
JESUS FUKING CHRIST!! IM SO PISSED AT GC AND IE RIGHT NOW! every time I write a big reply, it crashes when I send it and I lose everything... (it happened 4x times when replying to your PM... so you only got the shortened version of it lol )
Yeah man I know.... that reply I just posted was typed out and sent twice last night, both crashed and I went to sleep pissed LOL. I've learned now to copy/paste my longer responses into a notepad or Word document before hitting "Post", because its 50/50 it's gonna crash on me. Also happened twice with the OP....
So this was my reply haha : So you're getting there For the CLG, you are right about the voltage but, but the current will be way too high for your LEDs. If you were to hook up 3x 10V COBs in series with this driver, they would pull a total of 30V from the Driver, but if you remember that in series the current is not split, EACH COB will run at 4A, so they will most likely burn instantly If you have 3x 10V COBs that you want to run at 1.5A on the same driver you will need a driver that has an output of at least 30V and 1.5A. It would be true if you put them in parallel, they would require a driver that puts out a high current so they can split it equally, so in parallel you would need a driver that puts out at least 10V and 4.5A for 3x 10V 1.5A COBS, but you don't want to wire COBS in parallel... For the wiring itself, you need to create a loop that goes through each COB. You will hook the driver's + to the first COB's + and that COB's - to the next COB's + and so on, until you reach the last COB to which you will hook up the - to the driver's - so it will give you : Driver+ +COB- +COB- +COB- -Driver. And please do Ground your LEDs properly if you don't want to be shocked. The ground is simply the third wire on the AC side of the driver that needs to be hooked to the heatsink, so that if there is any short circuit, the ''lost'' current will go directly to the ground instead of trying to go through you when you will put your hand on the light. The CREE CXB3590 simply has two versions, one is 36V and the other is 72V, it is simply because of the way they are internally wired ( inside the COB you have a whole bunch of diodes that are wired in series and parallel, so changing the way they are wired will change the Voltage and Current needs ) So you can choose either model, you can't buy one and choose to run them on 72V or 36V, they are two different models.
Ok this is all starting to make sense. I'm still a bit confused when browsing around the web for COBs though. What exactly makes a COB good? Let's take the CREE CXA 3590 and CREE CXB 3590 for example. Which one would be 'better' and why? http://www.cree.com/LED-Components-and-Modules/Pro... http://www.cree.com/LED-Components-and-Modules/Pro...
The CXB is only a newer version of the CXA. I don't see the major difference between the two other than cxb is a bit better in efficiency.
And these CXB's come with the option of color spectrum as well right? http://www.alibaba.com/showroom/cree-cxb-3590.html I'm looking at that first link on the list, and it's from Kingbrite. 27, 3, 35, 4, 5, 65 are all available spectrums. Since my idea is to have these lights run the crop from veg through to harvest, would it be a good idea to get a variety of spectrums?
Yes, you have a multitude of spectrum to choose from, usually the 2700k and 6500k are not in stock, so they are a bit harder to find. But a mix of 3000k and 5000k is pretty good. You can use a ratio 3:1 (3000k:5000k) for flowering and the opposite for veg. For a full spectrum, I would probably add some 4000k in there to maybe ''even out'' the spectrum a bit. The 4000k still has some good red spectrum while giving out good blue. IMO I would probably do 2x 3000k, 1x 4000k and 1x 5000k (or 6500k if you can get some). Please note that is no way scientific, and is just a gut feeling haha
From the spectrum graph on the Spec sheetsfrom the CXB3590, it seems that getting the 3000k at 90CRI could be a good choice too, with that red peak more towards the 630nm range than 600nm
Ok I haven't forgot about this thread. I've been busy in the organics section figuring out how to build a proper soil for my future girls lol. I plan on putting together a hypothetical light fixture here on this thread and seeing if it would work, asking for feedback etc. Still have some questions though. 1. How many CREE CXB3590 would it take to make a fixture equivelant to a 1,000 watt HID fixture? If I wanted to put 9 of these COBs on a single fixture, for example, how strong would this light be and how many square feet could it cover with that strength? 2. Are there better COBs than the CXBs atm? I only reference them because Real built his fixtures with them, and people seem to praise his lights as top quality DIYs.
Its a bit hard to compare a 1000hps vs CXBs... but Real seems to have around 500w of cxbs... So imo I would say anywhere from 500w to 800w should give you similar results? But I really don't know... shoot him a pm, I'm sure he will give you his opinion based on his experience and for the 9 cxbs, it would depend on what kind of wattage they put out. In my experience, above 30w per square feet you are starting to get serious budz, personnaly I'm aiming at 40w per square feet. Above 50w psf would probably give you amazing results. CXBs are good but because of pricing I rather go with vero29s. You can almost buy 3 of them for the same price of a top bin CXB3590.
Organics is probably the easiest route and gives great results with minimal.effort! go organic! and you can say you have ecoenergetic organic weed when grown with leds hahahaha
Yeah.... The book is missing the last chapter... I thought from reading.... it was going down the DIY/LED trail start to finish... But like Amelia Earhart... Just disappeared... One thing... I "DO" have better understanding of the DIY... Maybe the answer IS here... Just gotta read it a few more times while studying the parts catalog...?
I am building a 2 x Vero 29 light. It will be ~106watt 13500 lumens. It's halfway done. Waiting on the drivers and a power supply for the fans. It will go together with my Mars 300. I can add more cobs if necessary later. If anyone is interested....