1 - 12 of 12 Posts

·
##### Registered
Joined
·
42 Posts
Discussion Starter · ·
i am looking to build a diy led setup for my 125g long, i was going to buy some 50 watt led outdoor floodlights from amazon till i herd the reviews on most of them. i found a score of 50x3 watt 10000k cree style leds. FV is 3.2-3.6v, and FC is 750mA. either i am super tired or just not looking in the right places, but i can not find a driver to run them. i also believe my math is wrong to. if each led needs up to 750mA and i have 50 of them i would need 37.5 amps(dont sound right). i am trying to do this with as few drivers as possible, 1 is best. thanks in advance

#### jeffkrol

·
##### Registered
Joined
·
13,144 Posts
i am looking to build a diy led setup for my 125g long, i was going to buy some 50 watt led outdoor floodlights from amazon till i herd the reviews on most of them. i found a score of 50x3 watt 10000k cree style leds. FV is 3.2-3.6v, and FC is 750mA. either i am super tired or just not looking in the right places, but i can not find a driver to run them. i also believe my math is wrong to. if each led needs up to 750mA and i have 50 of them i would need 37.5 amps(dont sound right). i am trying to do this with as few drivers as possible, 1 is best. thanks in advance

10 Crees connected +...-...+...-...+...-..ect.. needs 32-36v and you can drive them at 750mA

Connecting 5 of these in parallel you still only need 36v but now you need 3.75A.
So that would be the spec of a single driver...oh and power dissipation of 150W (generally add 10% safety margin)
"in theory" this is all you need, once you adj. the current to 3.75.. More of a "constant voltage" driver w/ constant current properties.. CLG-150-36
http://www.meanwell.com/search/CLG-150/CLG-150-spec.pdf
and cost would be \$55 or so and no dimming.
AGAIN I'm not guaranteeing this nor recommending a 1 driver approach for 50 LED's

Parallel strings has some design "issues"...that make them not as desirable as all in series..

For example if one of the 5 fails "open" then the current gets re-proportioned instead of 3.75/5 it becomes 3.75/4.. another fails and it becomes 3.75/3 =1250mA going into the final 3 strings and most likely burning them all out or, at the least, shortening their lifespan..
Another one: "not all strings" will be equal so you can have visual mismatches between strings.

a more reasonable approach would be using LDD-700's and 5 of them @ \$7 each.. (\$35) and 5 individual series strings
Coupled to a 36V power supply (3.75A, 150w+) @\$30 IDEALLY your PS should be 3 V over what you require. Driver loses 3v so it should be 39V..but that is another subject and to be honest your total V(f) will probably not be 3.6v x5
Your MINIMUM voltage for 10 in series is 32v plus 3v (35V) if using a ps driver combo.

That aside and the added parts count, pricing is close to the same and if you choose, each channel is dimmable separately..

to up the "specs" to fit the above more closely, just make the strings 9 LED's each x5.. Still plenty of light. (9x3.6=32.4v +3 = 35.4 )

·
##### Registered
Joined
·
42 Posts
Discussion Starter · ·
I like the dimmable idea. Do you have a model you would recommend. With 9 to a driver it gives me 3 extra for replacing if needed.

·
Joined
·
13,144 Posts

#### jeffkrol

·
Joined
·
13,144 Posts

·
##### Registered
Joined
·
42 Posts
Discussion Starter · ·
\$23 for 50x 3watt 10000k leds, \$35 for 5x ldd-700h drivers, \$90 for 5x 1.4" x 18" heat sinks, \$13 for coralux 5up ldd driver board, \$45 for pwm controller, \$30 for power supply, \$236 before tax and shipping. wife said NO!!! she put in a few other choice words that i would rather not share. looks like bad reviews or not, i am getting 3x 50 watt led flood lights. will just have to make sure i order extra drivers for them, take them apart, replace the compound with better stuff, make sure everything is tight, mount cooling fans ( i have a lot of them ) and reassemble.

#### jeffkrol

·
##### Registered
Joined
·
13,144 Posts
\$23 for 50x 3watt 10000k leds, \$35 for 5x ldd-700h drivers, \$90 for 5x 1.4" x 18" heat sinks, \$13 for coralux 5up ldd driver board, \$45 for pwm controller, \$30 for power supply, \$236 before tax and shipping. wife said NO!!! she put in a few other choice words that i would rather not share. looks like bad reviews or not, i am getting 3x 50 watt led flood lights. will just have to make sure i order extra drivers for them, take them apart, replace the compound with better stuff, make sure everything is tight, mount cooling fans ( i have a lot of them ) and reassemble.
Well that is about 1/2 the cost...

Do 4 up.. use "wires" (LDD-HW) and skip the board.. cuts the cost down by \$20..Salvage aluminum or use flat bar stock.. keep your LED's "in checK" so you can skip fans..Saves about \$40 in aluminum.. Funny how the LED's are the "cheap" parts.. w/ any DIY, it is always the "connectors" that kill you...

But I hear ya...

http://www.myled.com/p3494-led-proj...0v-grey.html?gclid=COKXldOCnr4CFRQmMgod40EAQw

Err.. why 10000K????

·
##### Registered
Joined
·
42 Posts
Discussion Starter · ·
I thought the higher the spectrum the better, as long as it was still "white".

·
##### Registered
Joined
·
42 Posts
Discussion Starter · ·
That is the style of 50 watt i am looking at.

#### jeffkrol

·
##### Registered
Joined
·
13,144 Posts
I thought the higher the spectrum the better, as long as it was still "white".
Relatively true...w a few gotchas.. It is higher in blue w/ less phosphors which emit in the "not blue" spectrum..
This causes a mild wash out effect of other colors.. i.e red,greens ect..
Plants don't care but people do..
Best way to look at it is it is an unbalanced white..
Also technically speaking deep red is "the best" wavelength but you wouldn't want a red tank either, If one were to do a clinical study on a "photon by photon basis" I'd suspect the "warm whites" would win.. Of course they have the same problem but in the opposite side of the spectrum.. more red, less blue, shortage in wavelengths in-between..not a good color rendering..

Oh and a bit of a corollary, you can't judge different 10000k type lights.. Their spectrum (cct) may add up to 10000K but what "colors" you add may be all over the board.

Between the color temps it is more of difference of quantity(low K LEDs are less efficient, generally) and look (difference in color response) than a quantitave "better" for plants..
This page gives a good "visual reference"...thought it is 10000k flour. vs LED.. and a 10000k led (remeber the addition thing) would not be as extreme but it is still a fairly valid example.. A 10000k LED is a bit more spectrally balanced.

If I had to pick one white.. I''d have to go somewhere in the range of 7000k-4000k

·
##### Registered
Joined
·
42 Posts
Discussion Starter · ·
My phone playing games with me this morning. Amazon has the same style of lights, for \$30, and i work for amazon, so discount lol. 6000-6500k. I am wondering if later i can replace the drivers with sizeable, and run a controller.