Prerequisites for a DIY LED build?

Okay I do realize this may have been brought up before, but (for now) this isn't about how to make a DIY light, but just to check if I *CAN* actually go ahead and build one. You know, before I go out and waste my money just to create a 400W fire hazard.

I can build PCs and learn new tech pretty fast. I do understand LED white papers and the like, but more for comparative reasons. I have *some* soldering experience, but those were just to repair faulty connections. And I'm not involved in the electronics, engineering, or any scientific fields (but I'm a scientist and botanist at heart), but I FUCKN WANT A COB LIGHT. BAD.

I could just buy a light from, say, GoGreenLEDs or A51, but they won't ship to my country. I would've bought from anywhere else, but since most effective, non-cob style proprietary lights are over $1000 the shipping and duties costs would be ridiculous.

And so... where do I begin? Do I even have the slightest chance of giving birth to a DIY cob monster?

You should be fine. Sounds like you have a little less experience than me, but this isn't rocket science. There are only two things you really need to power. The driver for the fans and the driver for the COBs. Do your research - Figure out what space you're working with, figure out which design you like best and feel most comfortable trying to emulate. Lay out your ground work - How are you going to cool them? You're overseas, so a CPU heatsink/fan combo is probably going to be the easiest to acquire. Get in touch with Jerry at Kingbrite on Ali. He's got all the drivers, COBs and lenses you'll need. You'll need wire - 18GA is fine. You'll need thermal paste, if you've been building PCs, you may have some lying around. So, I guess I would start by analyzing your space. Then, decide how many COBs you need to fill that space and come up with a design that would house/mount them. I'm using vinyl fence post from the hardware store. People use L Brackets with great success. I love how clean those builds are.

If you want to give birth to one, you must envision what you hope to create.

Hello Zulu Smoker,
I am in the same boat as you and have only been here a couple of weeks. My experience level is the same as yours and I live outside of America. I have 85%completed a veg light that will be my first DIY fixture. It is pretty straight forward. There is loads of intelligent and helpful people here and a wealth of information in the threads.
Spend some time reading and follow the advice from the more experienced folks here. Most are happy to answer questions. I found it all a bit daunting at first but I am really enjoying the process now.
HockeyBeard(great name) has already given you a good starting point.
I hope all goes well for you and look forward to watching what you come up with.

Cheers,
Will

Thanks for the input. I was hoping for some instant gratification and just focus on growing with the right equipment, but since that's not possible my botanical adventures will have to wait. I've actually been lurking around RIU for quite some time, and most of the popular threads have been greatly insightful for my decisions.

Oh I've got a plan all right. I just needed the lights.

Oh well.

Will Thayer said:

I hope all goes well for you and look forward to watching what you come up with.

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And I'll be watching your grow man, good luck. Much love in RIU.

Time to read up. And break out the toolbox.

Right, I understand I am the same. Others will chime in I am sure.
SupraSPL has graciously provided a shed load of good information. If you go to this link he has laid out a few builds you can work with: https://www.rollitup.org/t/cxb3590-1500w.878136/page-2 post # 32

Most folks talk to a gentleman in China named Jerry. [email protected] he can give you good prices on COBs and drivers. I am in Europe and COBS plus drivers cost me $40 shipping.

Hope this helps you on your way to building the light you want.

Cheers,
Will

Great stuff Will, I appreciate the help. $40 is manageable compared to the shipping and duties I was facing with a complete light - hearing this is also a morale booster. I was thinking of making a 9-cob light in a square layout to fit a 4x4 tent. I really wanted to make it all out of aluminum or of similar material, but since I have no access to metalworking tools I'd have to look up and find inspiration on what materials to construct it out of. The thought of running 450W through 9 cobs and making it safe while running for the next fifty or so thousand hours is my real fear - so much that if I don't feel confident enough I'd have to find an electrician or something. Though that isn't really wise if I wish to keep my ops stealthy.

Maybe I should just draw up some plans and talk to a metalworking shop, while keeping all the electrical work to myself and ask help only if it's delicate stuff. That way no one's the wiser. I'm really into the light bar design and how efficient is with space and airflow. BML's Spyder employs a design I'd like to emulate, passively cooled to minimize electricals and risk of overheating when a fan goes out. I'll let the tent's airflow take care of the radiated heat. I'm still on the fence whether to get 3070s or 3590s but from an efficiency standpoint I'd like to get the best I can. And there are A LOT of other considerations - 36/72V, tools/meters necessary to tweak the voltage properly, drivers... If I'm gonna spend a lot then I might as well spend wisely. And once only if possible.

Hm that actually sounds like a plan.

After reading and listening to the folks here I decide for my square metre 3.3ft x 3.3ft (10.89sqft) area to go with SupraSPL's advice:

"16 x CXB3590 3500K CD 36V @ 700mA (23W ea) you would get 64% efficiency and can run 8 COBs on each HLG-185H-C700 driver."


Running the COBs @ 700ma gives the best efficiency but cost more in COBs and drivers. You could run less COBs at higher current with less efficiency. This is stuff I have learned here by reading and straight up asking questions until I understood what people was talking about.

I do not know how far you are from Europe, I got my heatsinks from tme.eu (1000mm x 150mm x 15mm) for a nice price and cheap shipping.
I will place 4 x COBs per heatsink.
You can do it yourself with some research and asking the right questions. If you get COB holders you would not even need to solder.

You going about it the right way, take your time planning it all out and asking others what they think. It will happen and you will be happy for sure.

Cheers,
Will

I don't think you need 16 3590s to cover a 3.5x3.5, do you? If cost is an issue, you can drive them harder and use less, and still be over 50% eff.

HockeyBeard said:

I don't think you need 16 3590s to cover a 3.5x3.5, do you? If cost is an issue, you can drive them harder and use less, and still be over 50% eff.

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Yeah I know but I am an efficiency junkie and the price falls within my budget. The space will be expanded in the future as well. I also have height restrictions and the space gets a bit warm in the summer months.Also the price of electricity fluctuates from tolerable to extortionate in Europe.

Cheers,
Will

Makes sense to me! Sounds like you know what you need for your space.

Will Thayer said:

Yeah I know but I am an efficiency junkie and the price falls within my budget. The space will be expanded in the future as well. I also have height restrictions and the space gets a bit warm in the summer months.Also the price of electricity fluctuates from tolerable to extortionate in Europe.

Cheers,
Will

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I have the same concerns with heat and electricity costs. I have a few local sources of CMH from OSRAM (up to 250W) and Philips (their popular 315W) but they'll literally bake the plants. Power rates border on extortion.

16x3590? That's a lot for your space! Your plants will surely love it.

What's the primary difference in performance/efficiency when comparing 36V/72V 3590 COBs? I'm not sure if the costs are the same but I'm guessing chips and drivers difference would be minimal?

I've yet to shoot Jerry an email, want to make sure I don't rain down inquiries on him without doing proper research. Also don't want to look like a fool.

This is their site right? http://kingbriteled.en.alibaba.com/

The 36V and 72V perform the same on paper as far as power and efficiency. They just match up with different drivers.

The 36V is a good match for the HLG-185H0-C700 driver to run 8 COBs at 23W ea. It is also a good match for the HLG-185H-C1050 to run 5 cobs at 36W ea or HLG-185H-C1400 to run 4 cobs at 50W each. The 36V could also be used for the HLG-320H-36 or even the HLG-600H-36 although I have not tested it.

The 72V is a good match for the HLG-185H-C700 to run 4 cobs at 50W ea. The HLG-185H-C1050 can run 2 COBs at 75-80W ea, not a perfect match but still very good.

HockeyBeard said:

Makes sense to me! Sounds like you know what you need for your space.

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To be honest, Two weeks ago I had no idea what I needed. I took in all the good advice given by the community here and applied it to my grow space. I am grateful to have such a resource.

Zulu Smoker said:

What's the primary difference in performance/efficiency when comparing 36V/72V 3590 COBs? I'm not sure if the costs are the same but I'm guessing chips and drivers difference would be minimal?
This is their site right? http://kingbriteled.en.alibaba.com/

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I went with the 36v because I could run more COBs per driver(heavy to ship). Less money on drivers but more money on COBs @500ma.
That is their site but you will get more out of emailing them. Best prices bar none. I even asked a few other Chinese companies for quotes but no one offered better prices.

Thanks for the infos guys. I'll shoot Jerry an email first thing Monday.

Since I don't have any drills or tapping tools, I was thinking of using Arctic Silver Thermal Adhesive to install the cobs on the heatsinks. It's got a temp range of -40C to >150C. I'm not sure how hot these cobs get but >150C is enough for these, right?

Hello Zulu,
Sorry for late reply. I've been on a plane for 12 hours = sucks.
From what I have learned from reading the forum. SupraSpl and others have had success using thermal paste/grease and securing it with kapton tape. I think it forms a vacuum and the tape keeps the COBS from shifting and breaking the seal. I am clumsy and accident prone so I am going with COB holder and a table top drill press. Plus I feel all manly using tools.
I do not think DIY Led is a cheap option. You will spend coin no doubt. Do you have tool hire companies where your at? Once you have built your fixture it should pay dividends over the course of your grows.
I must admit some of the information here seemed counter intuitive at first but when you look at things long term it makes good sense.

Cheers,
Will

Zulu Smoker said:

Okay I do realize this may have been brought up before, but (for now) this isn't about how to make a DIY light, but just to check if I *CAN* actually go ahead and build one. You know, before I go out and waste my money just to create a 400W fire hazard.

I can build PCs and learn new tech pretty fast. I do understand LED white papers and the like, but more for comparative reasons. I have *some* soldering experience, but those were just to repair faulty connections. And I'm not involved in the electronics, engineering, or any scientific fields (but I'm a scientist and botanist at heart), but I FUCKN WANT A COB LIGHT. BAD.

I could just buy a light from, say, GoGreenLEDs or A51, but they won't ship to my country. I would've bought from anywhere else, but since most effective, non-cob style proprietary lights are over $1000 the shipping and duties costs would be ridiculous.

And so... where do I begin? Do I even have the slightest chance of giving birth to a DIY cob monster?

Click to expand...

YES, you can do this. I was in the exact same boat as you, not sure if I could pull it off. But honestly, now that I've done it, the physical assembly is not that tough. I used Cree cxa3070s, with cob holders and Arctic PLUS fans. The physical assembly required the following tools/skills (if you make other design decisions, like not using COB holders, some of these may be moot) - Ability to use a multi-meter, pigtail splices and wire nuts to divide 120V to drivers and power to fans, drill press and tap/die to mount holders, crimping tool, bullet connectors and heatshrink to connect power to drivers, ability to solder 16g wire to 30g wire (hooking up fans), ability to splice wire, hacksaw and drill to assemble frame (NOTE: building a 90 degree jig to drill holes in two pieces of aluminum was very useful, just an FYI). The only really spendy thing is the drill press, the option then is to mount with thermal adhesive and kapton tape, then you have to solder leads to cxa's - both of those options require some basic skills, but nothing insurmountable.

And there is a TON of useful help on these forums. When I did run into problems, I posted a couple of questions and got almost immediate answers that helped me resolve the problems. Now, I'm on day 30 of the first run with this bad boy, and loving every minute of it.

Everyone has their own journey based on a blend of their native abilities, experiences, and personality. The advice you'll get is generally an individual responding to their limitations or issues. For instance, my advice would be to seriously take your time with the build process. 90% of the issues I had/have were from being impatient. I also think a drill press is a really good idea -- I did mine with a hand-held drill and some of my holes (on my first build) are not perpendicular and so my COB holders are under odd pressures as the heads of the screws sit slightly off, or the screw began to torque off center as it went in at a slight angle... It works, but I don't know what the long term effect will be. This is one thing I would have liked to have done with far more precision than I did. At least my second one is much cleaner than the first, so I did learn something from it.

For a comical visual to get you started, this is a heatsink I broke 3(!!!) drill bits in, and had to keep shifting positions for the COB holder. As a side note, I did not drill and tap per se, I pre-drilled (to just under the thread size) and then used self-tapping screws. This heatsink is currently in use, with the drill bits still inside...

Lol @Humanrob - this is EXACTLY what I was afraid of. I mean, I can be anal with measurements and stuff but sometimes the skills just aren't as well-honed as a veteran's.

I was considering putting the ideas on paper and going to a machine shop for them to execute, but that would certainly cost me a bit @Will Thayer. I was planning to head over there and ask them to drill all the holes and do other things that I will not be able to do by myself (with my limited toolset) while keeping all assembly and actual construction to myself, so that's certainly in the works.

I'm trying to make things sturdy and consolidated like a real grow light (I'm digging @REALSTYLES cob monsters - that's what I'm trying to achieve in essence) but real simple. And safe. Definitely safe.

I hope I'll be as successful as you @Sonnshine, for a noob with no actual electrical DIY under his belt this is actually tough. There are no hard set rules or instructions around, but the "recommendations" given by @SupraSPL earlier in the thread is A LOT OF HELP (as well as everyone else's contribution actually). I've had to go back to basics to try and understand what makes a working LED fixture and what are needed to drive/power it, considerations when deciding which components to buy, and looking up OLD successful builds at the DIY thread.

One thing I've noticed is that this fora is a frickn wealth of info and some stuff needs to be sticky'd or something. Though that does entail a lot of work it would've eased the transition from consumer to builder (at least from my perspective). We've got the collective ideas and findings of the community but it's not as apparent to everyone at first. Maybe that's what made a lot of the people here experts, because they actually had to THINK for themselves and ACT upon their ideas rather than just follow a tutorial.

Oh, I wouldn't complain if there was a tutorial by the way. Though some would argue it would promote laziness and complacency, but hey... back to doing research.

As a follow-up question: What is the general consensus for the amount of light needed for veg in terms of # of cobs/area? I've come up with a possible 4x2 or 3x3 3000K CXB3590 configuration for an initial mixed-veg/flower 4'x4' tent, but with the future plans of creating a dedicated veg tent in a smaller 2'x2' (or so) space and making the bigger tent flower-only. I was thinking of using a 2x2 5000K CXB3590, but should I go less (or more)? Power savings are always welcome, but happier plants are also good - just trying to make the economical decision here.

Also planning to run the cobs at around 50W or less, so also keep that in mind. 400-450W for the big one and a smaller 100-200 (or higher?) watter. Excited.

Just found out Optic Lighting is shipping to my country (at least according to their eBay page) through the eBay Global Shipping Program. Stoked. Let's see if the costs surmount the impending DIY sweat.