Central DIY LED Link location- Beginning to End!

Scotch089

Scotch089

Well-Known Member
I have been browsing the pages of RIU for some collection of years now and love where technology it progressing. I have found several threads with scattered information about building your own LED's. I would LOVE to pursue designing and building my own grow lights, especially on the edge of technology as it is.

But i feel like when I sit down and dedicate hours of research to it and try to find where to start.. I'm at a loss, i cant find the simple basics of understanding ie why it matters what "kind" of LED you use (Cree, bridgelux, etc), what is the usual current each led is ran at? How? How do you set up drivers?

How do you even know what heat sink to use and how to?!?!

Okay..step back and breathe...

I personally wanted to start a thread for "a beginner's guide" kinda deal that points me to where I need to be, but thought thats cutting the potential of this thread short as the depth of this topic is well beyond me.

So basically now, I wanted to start a thread to centralize links to get ppl "on their feet" and moving on their own journey into the DIY LED World, along with any in-depth links to journals, threads, or articles that help us further understand what we need to do in order to be self-sufficient.

(This is coming from a guy that can set up car systems and has common sense and simple problem solving...I'm just clueless as to where to start with building a light from scratch... I am dying to find out!!!)
 
Bumping Spheda

Bumping Spheda

Well-Known Member
Cool thread. I'll take a crack at it.

Q: How much heat sink do I need?
The range of heat sink surface area that KNNA recommends for passive cooling is 125-150cm2/watt of dissipation. "Watt's of dissipation" being the total number of Watts that your LED panel consumes at the plug, minus the LED driver. This is a very generic rule of thumb and is designed to maximize lumen maintenance to >90% for 10 years, maybe more.
Q: Does it matter what brand or bin LED's I use?
Efficiency is important. The more efficient your LED's are the more light you produce for every Watt that you consume (read less heat, more light). We build LED panels to grow plants, not heat the room. For some there is a balance between top dollar LED's and what's "good enough." You can grow very well with cheap LED's, and yet that same exact grow with more efficient LED's should achieve a higher grams/watt ratio.
Q: What current should I run my LED's at?
You'll have to check the spec sheet for the specific LED's that you want to use. If you have proper heat sink cooling and you're confident in that department you can probably get away with 1.2-1.4x the "current test" that the manufacturer used without sacrificing too much of your LED's lifetime. An LED's efficiency does drop past a certain point, however, so although the LED may be pumping out more light it might be better to simply use more LED's at a lower current. At point does LED efficiency drop? It's different for every LED.

I'll quote SupraSPL
If you are not an LED geek this might save you some time. When comparing LEDs for growing it all comes down to radiometric efficiency. Here are the calculated numbers of the very best from this list. The numbers are @ actual operating temperatures (Tj 50c) and represent the minimum output of these bins. Actual output will be higher.
@350mA (ES royal blue 63%) (XT-E warm white 41.5%) (ES deep red 42%) (XP-E red 48.2%)
@500mA (ES royal blue 59%) (XT-E warm white 38.3%) (ES deep red 40%) (XP-E red 45.9%)
@700mA (ES royal blue 55%) (XT-E warm white 34.8%) (ES deep red 38%) (XP-E red 42.4%)
Click to expand...
Q: What driver do I use?
Your LED drivers should be "constant current" (CC) meaning that as you add LED's in series and the total circuit resistance rises, the LED driver intelligently pushes a higher voltage in order to keep the current at a flat, "constant" rate. LED drivers are rated at a certain wattage, or within a wattage range.
Watts = Volts x Amps
First, you need to match the output current of the LED driver to the current that you want to run your LED's at. Now, in order to choose the correct output voltage, you take the number of LED's you want to power and multiply it by their voltage rating.
Example: 36, 1Watt LED's at 2.2V = 36 x 2.2V = 79.2V
As long as your desired LED driver has a voltage output that 79.2V falls within you're good to go.



Random link
https://www.rollitup.org/led-other-lighting/590648-diy-led-220w-cree-xte.html
Lot's of good information here.

It's also important to aim for a good $/watt ratio. $1/W after everything is said and done seems like a good value to strive for. Shop well!
 
Scotch089

Scotch089

Well-Known Member
Hey i really appreciate that Spheda, great way to get the ball rolling!

I was even just throwing those questions out as examples to my thought process, or lack there of lol but you fuckin nailed it!

Thank you brother
 
FranJan

FranJan

Well-Known Member
There should be a thread for links period, not just for DIY stuff. Beginner or Pro, there's no escaping some reading/studying with LEDs. Here's two sites off the bat people should be using to learn. And y'all should be ashamed of yourself if you don't already have them :-P.

http://donklipstein.com/index.html- Probably the best collection of links and info on LEDs, or light for that matter IMO. For beginners to all you "pros" out there ;).

http://www.ecse.rpi.edu/~schubert/Light-Emitting-Diodes-dot-org/- The Dean of LED. Everyone using/building LEDs should have a copy of his book, (along with Power Supplies for LED Drivers by Steve Winder) on their Comp/phone/tablet. Even if you can only read the indexes' right now :).

Reading wise I like these places;
http://www.sslighting.net/- The Source.

http://www.led-professional.com/

http://ledsmagazine.com/

http://www.electronicsweekly.com/components/displays-opto/- EW's Opto section

http://www.ledjournal.com/main/

And a link to see what Google News finds about LED Lighting today. (No re-direct. None of that BS, https),- Click Here



Good Luck with the thread Scotch. You should look for vids on YouTube that deal with beginner DIY if you got the time. Peace.
 
Scotch089

Scotch089

Well-Known Member
lil somethin somethin..

https://www.rollitup.org/led-other-lighting/580314-super-easy-diy-led-micro.html

Though he suggests a 5:2:1(R:W:B) instead of 9:2:1, so I spent last night breaking down the %'s of each watt as I've heard this is a more reliable way of going about things. I took %'s for to see what the differences are:

9:2:1- 75% red
7:2:1- 68.75% red
5:2:1- 62.5% red

Thinkin I might go right in between with the 7:2:1, May even go 8:3:1 with two WW and one NW to kind've balance the lack of blue

8:3:1-67% red, 25% white, 8% blue

This is designs for a flower panel, Im not really wanting to overdo it on the blue's, enough to make em happy happy happy.

Any input would be greatly appreciated!

Ill keep posting links I stumble onto to help every body!
 
Scotch089

Scotch089

Well-Known Member
Helllllll yea, I have enough reading material for the holiday! Thank you guys!

BUMP! any one have input on those ratios I tossed out there? Or anyone care to speak to the Neutral, Cool, and Warm whites on what you think each individual diodes' positive and negatives are?
 
S

SnotBoogie

Well-Known Member
Bumping Spheda said:
Cool thread. I'll take a crack at it.

Q: How much heat sink do I need?
The range of heat sink surface area that KNNA recommends for passive cooling is 125-150cm2/watt of dissipation. "Watt's of dissipation" being the total number of Watts that your LED panel consumes at the plug, minus the LED driver. This is a very generic rule of thumb and is designed to maximize lumen maintenance to >90% for 10 years, maybe more.
Click to expand...

I think this is rather high.

[h=2]150 centimetres = 59.0551181 inches[/h]

I was under the impression people recommended more like 27 inches per watt (70cm squared) for passive.
 
jubiare

jubiare

Active Member
19-21 square inches for every watt burned! (even slightly less with latest generation efficiency ones ... generating less heat, they'd need less dissipating area! for those kind of equations supra is the guy who can help)
 
Bumping Spheda

Bumping Spheda

Well-Known Member
No idea, stole it from a Knna thread, iirc. Perhaps he means total surface area of the fins? I got very little clue, but that does seem insanely high.
 
FranJan

FranJan

Well-Known Member
For all who've never read it, here's where the KNNA thread is. My apologies to any mods for posting links to other MMJ forums but this one is a practically a historical document.

KNNA Thread
 
Bumping Spheda

Bumping Spheda

Well-Known Member
Well there we go, he says 9in^2/W for active, 21in^2/W passive as minimums. More is encouraged.

Thanks for the link, FranJan.
 
jubiare

jubiare

Active Member
Bumping Spheda said:
Well there we go, he says 9in^2/W for active, 21in^2/W passive as minimums. More is encouraged.

Thanks for the link, FranJan.
Click to expand...
YES, because in a few years diodes efficiency has improved, and if efficiency is higher heat is less .... I have kind of gone to say 19 square inches can be safe as it was 21. But for the latest diodes like cree xte you need even less heatsink apparentely! Supra has done some calculations on it
 
jubiare

jubiare

Active Member
the concept is simple, let's take 1.3 watts of a red chip .... all of that that is not efficiency is translated in heat. So more efficient (latest gen) translates in less heat! In general you can have quite different stories with same watts panels, some are more heat than photons and vice versa!
 
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