Help and advice for building a LED unit

[DennisC]

As above, I am considering building a LED setup for my ATS.

My screen is 6" x 6" and the effective size of the lights can be 7 1/2" x 8 1/2 ". My initial thoughts are 4 red and 3 blue to each side (each 3w)

What I want to know apart from is the lighting suitable is basically - how to do it and what other parts do I need. As you can guess, I know nothing about

electrical work. Any thoughts, ideas and info gratefully accepted.

Dennis

[kotlec]

4:3 Too many blue.

[Ace25]

I agree, 5:2 or 6:1 on the red:blue ratio.

rapidled has most of what you need, and even solderless options. leds, adhesive, heatsink, drivers.

ledsupply.com has a product called LED Seal (http://www.ledsupply.com/9013-07.php) that will spray a protective silicone layer to protect the LEDs if they won't have any type of casing or splash shield.

[Floyd R Turbo]

I would go 6:1 or even as far as 8:1 on the blues. 4:3 is definitely way too much blue.

[DennisC]

Still at the thinking about it stage at the moment but looking at the Rapidled setup for easey fitting, but thinking of the 6:1 ratio on each side as the solderless units come in 7 fittings

[Ace25]

I would go 6:1 or even as far as 8:1 on the blues. 4:3 is definitely way too much blue.
With what you learned today, do you still feel that the case? I am thinking 5:2 is now looking even better, 1x 455nm and 1x 420nm for the blues.

[Floyd R Turbo]

Well those studies I keep referring to that NASA and I think Cornell did that showed the ratio of I think 6.5:1 red:blue keeps coming back to mind, the question that is still nagging me is what was their unit of measurement to arrive at that ratio. It is radiant flux, par, wattage, etc. The anecdotal evidence suggest that just going by a pure # of LEDs ratio gets you pretty close. Also this seems to have been mimicked to a large extent by more of the plant-growth fixtures you see on the market. My guess is that they followed what their customers wanted. In the initial stages of the LED grow light industry, I'm sure there were all kinds of experiments with all kinds of plant types that generally arrived at some kind of seemingly optimal ratio, and thus this is why everyone now makes fixtures with this ratio - because it is what works. The hydro guy who helped me design my fixture basically said do 7:1 ratio of LEDs

[Ace25]

Totally understand all that, but that is for terrestrial plants. When throwing saltwater and the bacteria into the mix, it is appearing more and more that the blues have more of a positive effect for our needs than they do for hydro.

Here is another one that will get your brain spinning.

On terrestrial plants, Blue = Vegetative growth, Red = Flowering. I have seen some recent LED grows using only 420/455/475 blues for the entire veg cycle and then switch to 8:1 reds when it comes time to flower.
http://www.advancedledlights.com/products/NEW-%252d-All-Blue-Extreme-Veg-LED-%252d-USA-Made-LEDs.html

[DennisC]

Getting more confusing now guys. Had made my mind up to go 8:1 but now it looks like it may/should be 7:2.

I have been looking at the Satisled LED's and my order when I get round to doing it will be

1 x driver for 18 x 3w
4 x heatsinks 240 x 76 ( will need 2 each side )
14 x 3w red high power LED's (660-670)
10 x 3w royal blue high power LED's (have to buy 10 as min order no.)

My only question now is, do you wire up + to + etc or + to -

Told you I don't understand electrics.

Dennis

[Floyd R Turbo]

Algae doesn't have a vegetative part of the cycle as far as I know. People who have tried to grow algae using only RBs or CWs get growth, but reds get better growth. Also look at the SM100 test with the e-shine fixture, and all the other tests he has done. If 5000-6500K worked better than 2700K, everyone would be using it. Blue alone doesn't work, heavy in red works, bottom line. 6:1 to 8:1 ratio. I see no reason to stray from that range.

[kerry]

Even my 4 660 reds to 1 blue 445 seems to work fine.

[Ace25]

Algae doesn't have a vegetative part of the cycle as far as I know.
That makes no sense to me. Vegetative growth is any growth in which the plant is not flowering/producing fruit. Algae is 100% vegetative growth, 0% flowering.

As far as I know, I have never seen anyone, including Santa Monica, try all blues for growing algae. I have seen Melev write in his cheato article that bluer light grew chaeto much better than warmer white light. I think it is something one of us at least needs to try out and see how well it works, if at all, before we blindly say it won't work. Now do I think all blue is the "correct" answer, no, not at all, but I think it would be an interesting experiment to try.

[Floyd R Turbo]

Yep I agree, it would be interesting to try it. I just think that comparing the vegetative/flowering cycle to algae isn't an apples-to-apples comparison, I guess I should have put it that way.

W/R to Melev's article on the 5000K vs 3500K lamps, again, not a good comparison either because each manufacturer of lamps could have used a different phosphor combination and there are many other factors to consider, so it was hardly a scientific result. Then if you compare the growth the people were getting when using 5000K or 6500K lamps based on that info from Melev, they got horrible growth, which turned right around when switching to lower kelvin lamps.

[jwoyshnar]

Be aware satis led's 18x3 driver is 220 volt and made for European setups. Check the voltages before you buy.


Getting more confusing now guys. Had made my mind up to go 8:1 but now it looks like it may/should be 7:2.

I have been looking at the Satisled LED's and my order when I get round to doing it will be

1 x driver for 18 x 3w
4 x heatsinks 240 x 76 ( will need 2 each side )
14 x 3w red high power LED's (660-670)
10 x 3w royal blue high power LED's (have to buy 10 as min order no.)

My only question now is, do you wire up + to + etc or + to -

Told you I don't understand electrics.

Dennis

[Floyd R Turbo]

Wiring + to + and - to - puts them in parallel, meaning you split the current and thus lower the output. Unless you're planning to run parallel strings and understand exactly what you're doing you do not want to do this.

The voltage drops across the LED from + to -. Diodes (the "D" in LED) only work one way, so the first connection to the + side of the driver module goes to the + on the first LED. Then you connect the - on that one to the + on the next and so on with the last - connected to the - on the driver.

You're going to want to google or youtube search how to solder LEDs etc, pre-tinning pads, pre-tinning wire, attaching LEDs to heat sinks, etc, before you get started. It's not like it's that difficult but a little research will save you a lot of headache.

[Ace25]

You made that sound more complicated than it really is Floyd (your way does work, just makes it sound more complicated to those who don't have an understanding on how it works). I never put + to + or - to - when doing parallel strings. I simply wire the strings as I normally would, 12 in a row, 2 rows, and then take the +/- wire from the driver and connect 2 wires on the end of each one to split them, then each one goes to the strings. The way you describe will make a "cleaner looking build", no question there, but just requires a little more brain power to get it figured out ahead of time. ;) Parallel strings do add another level of complexity, but really, not much. Just make sure each string is identical and know that when you split a driver to run 2 strings, each string then only gets 1/2 of the current output of the driver. If a driver outputs 1050mA and you run 2 parallel strings, each string will get 525mA.

When doing parallel strings though, you must make sure you use the same LEDs in each string to match the forward voltage. You have to use the same amount of LEDs per string as well as the same vf. Putting a string of 700mA china LEDs in a parallel string with a second string of XP-Gs would not be good to do, but if you mixed in equal amounts of China + XP-G in each string and never went above 700mA, then it would work.

[Floyd R Turbo]

I know that but the guy asking for help was asking a pretty basic question when it comes to wiring so I wanted to explain it in a basic manner.

[DennisC]

Thats me, very basic. I think you have answered my question. Basically, take 1 wire from the driver to + ve on the 1st LED and then 2nd wire from -ve on 1st LED to +_ve on 2nd LED and so on untill last LED - ve to driver.

I think it would be a lot easier to get someone to do it for me. I have rewird my house in the past, but as I get older, just not as confident especially with electricity and water.

Dennis

[Ace25]

Don't be afraid, it is really much more intimidating in your head than it is when you attempt to build one. If you wired a house, LEDs are about equal in difficulty. Once you build one and sigh a big breath of relief when they all turn on the first thought most people have is "That was it? That was so easy! Why did I make it out so much harder than it is." It is really as simple as connecting wires + to - on the LEDs. I found hooking up T5HO ballast and MH ballast much more nerve racking (more difficult to figure out the wiring on T5HO and the fact you're playing with high voltage makes me more nervous working around them).

[DennisC]

Next BASIC question.

I am fitting a heatsink to each side of the present scrubber and each 1 will be 10" x 7". The heatsink is from heatsinksusa and are finned 2" deep. I will be fitting 9 x 3W LED's to each heatsink and each one will have a seperate driver.

With the heatsinks being in an enclosed space, will it be neccessary to fit a fan to each side?

Dennis

[kerry]

The fan would not hurt any.

[Floyd R Turbo]

I'm sure if you send an e-mail to rapidLED they would tell you that you would not need a heat sink for such a setup. That's overkill IMO, no need for a fan.

[DennisC]

I will try it without then first and if it gets to warm, I will fit one afterwards.

Cheers

Dennis