# diy led lighting assistance needed



## alfred3 (Jun 16, 2020)

Hi all
My first attempt do build a diy led light for planted aquarium 120cm /60/45
I search the net for info and more i read more got confused
I know i want to use cree leds. Cool /warm white, some red and blue also. And use a dimmer
Any guidance will be Welcome.

Thank you


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## mistergreen (Mar 3, 2007)

There's plenty of instructions on youtube.
You'll need to buy lots of things like drivers, heat sinks, pots for dimming.
Check out these guys for info and supplies.
https://www.ledsupply.com/diy-led-projects

Manufactured LED lights are cheap enough these days you don't need to DIY. You do it for fun of building instead of for saving money.


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## alfred3 (Jun 16, 2020)

hi mistergreen

thank you for the replay . i want to build with cree leds , how many units you think i need to buy for my 120 cm tank ?


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## mistergreen (Mar 3, 2007)

It depends which cree LED you choose. I made one where I had 3 or 4 LED for 60cm. So, double that for 120cm.


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## alfred3 (Jun 16, 2020)

what you suggest is a 5w led xml 2 will be enough ? i am intending to upgrade to high tech tank in couple months

https://www.cree.com/led-components/products/xlamp-leds-discrete/xlamp-xm-l2


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## mistergreen (Mar 3, 2007)

I'm not an expert on cree but maybe 8.


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## alfred3 (Jun 16, 2020)

40 W for 300 liter high tech ?


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## hoppycalif (Apr 7, 2005)

Are you going to put lenses on the Cree LEDs? Lenses greatly increase the intensity of the light unless the light fixture is sitting right on top of the tank. I haven't been keeping up on the latest Cree LEDs so I can't say how many of which ones you should use. When I started making LED lights I started by studying LEDs and how they work, plus how they should be powered. Only after I learned all I could did I try to make a light fixture. My first step was to test a single LED using a PAR meter to get data on how much light one would produce vs. distance. It was a very interesting DIY project, and also very rewarding at that time.


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## alfred3 (Jun 16, 2020)

i understand . what is the ideal par for high tech tank? 
can you direct me for some informative links ?
thank you


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## mistergreen (Mar 3, 2007)

You want 50-60PAR at the substrate. That's considered high light. So that's about 55cm for your tank.
Your cree specs says Max Light Output (lm)	1052 lm. It doesn't say at what distance though.

You can convert lumens to PAR or PPF roughly.
https://www.waveformlighting.com/horticulture/convert-lumens-to-ppf-online-calculator


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## hoppycalif (Apr 7, 2005)

mistergreen said:


> You want 50-60PAR at the substrate. That's considered high light. So that's about 55cm for your tank.
> Your cree specs says Max Light Output (lm)	1052 lm. It doesn't say at what distance though.
> 
> You can convert lumens to PAR or PPF roughly.
> https://www.waveformlighting.com/horticulture/convert-lumens-to-ppf-online-calculator


Lumens are the total amount of light emitted by the LED, not the intensity - amount of light on a surface per square meters. So, there is no way to convert lumens to lux or PPF. You can make a crude conversion from lux to PPF (PAR units), but you really need a PAR meter to measure that actual intensity. And, that reading varies with distance from the light source.


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