LED Lighting please share you knowledge

[rolexbene]

I Have been looking at the possibility of building a tank with LED arduino controlled lighting, looking at maybe a build similar to this one, http://www.ultimatereef.net/forums/show ... p?t=530699
I am looking at a maybe around a 60l cube tank, so I am looking for sufficient lighting to cover this.
So my problems I am having are working out what LED's to use with what driver, I think I want to use Cree led's and I have noticed that many people are using these with Meanwell drivers.

The questions I would like help with are:
How many 3w cree led's would I need for high tank lighting?
Do I need to use Meanwell drivers or can I use cheaper chinese counterparts?
How do you work out what driver I need for the amount of LED's?

Thanks for any light anyone can shed, cheers. :idea:

 

[Piper]

I have built a couple of these systems using cree LEDs and a ready made Rapid timer/dimmer. I have not posted yet because of time issues and the dimmer does not seem to dim very much. I'm going to get some different drivers and see if that makes a difference. Also waiting on a new light to convert to LED as I currently have them on lengths of wood across the tank.

I have got 14 Cree LEDs but this will be double once the light housing comes. That's over a 100x50x50 tank. It's not really enough light. But I think 28 crees will be okay. With LEDs the more the better and dim them to get the require light levels. This way you get a very even spread of light.

I have a mean well ELN-60-48 driver. This will give upto 48v but can be reduced to a 24v if you had less LEDs on a string. Each of my LEDs has a nominal forward voltage of 3v, so 14 LEDs x 3v = 42v so I have reduced the voltage out of my drier to 42v. You then need to decide what current to run your LEDs at. The driver I use has a max of 1.3A, but the LEDs have a max of 1.0A. So this is your starting point, adjust your driver to 1.0A as a max. You can then reduce that as required if its to bright. This is the bit I haven't got write yet because the min dim is still very bright although I do see a difference. The Rapid dimmer sends out a 0-10v signal to dim my lights over a 6,8 or 10hr photo period. Spec sheets as below. I would use any driver so long as it matches the spec requirements of your LEDs.

http://www.vinnymarini.com/pictures/rap ... Manual.pdf

http://www.meanwell.com/search/eln-60/eln-60-spec.pdf

 

[rolexbene]

Brill thanks for the advice, i am thinking if i was to do an arduino controlled light i would need a dimmable driver that worked with PWM. Can I ask, were did you purchase your supplys from and how much did you pay, also what type and colour Cree's did you buy?

I have built a couple of these systems using cree LEDs and a ready made Rapid timer/dimmer. I have not posted yet because of time issues and the dimmer does not seem to dim very much. I'm going to get some different drivers and see if that makes a difference. Also waiting on a new light to convert to LED as I currently have them on lengths of wood across the tank.

I have got 14 Cree LEDs but this will be double once the light housing comes. That's over a 100x50x50 tank. It's not really enough light. But I think 28 crees will be okay. With LEDs the more the better and dim them to get the require light levels. This way you get a very even spread of light.

I have a mean well ELN-60-48 driver. This will give upto 48v but can be reduced to a 24v if you had less LEDs on a string. Each of my LEDs has a nominal forward voltage of 3v, so 14 LEDs x 3v = 42v so I have reduced the voltage out of my drier to 42v. You then need to decide what current to run your LEDs at. The driver I use has a max of 1.3A, but the LEDs have a max of 1.0A. So this is your starting point, adjust your driver to 1.0A as a max. You can then reduce that as required if its to bright. This is the bit I haven't got write yet because the min dim is still very bright although I do see a difference. The Rapid dimmer sends out a 0-10v signal to dim my lights over a 6,8 or 10hr photo period. Spec sheets as below. I would use any driver so long as it matches the spec requirements of your LEDs.

http://www.vinnymarini.com/pictures/rap ... Manual.pdf

http://www.meanwell.com/search/eln-60/eln-60-spec.pdf

 

[Piper]

I went for the Cree xp-e from cutter on 20mm star boards. Mine were a little too yellow. I got 3w heat sinks from HK the Alu circular ones. One per LED. Driver and dimmer were off a random sale on eBay. Can't remember how much I paid. Think the drivers were about £20 each and the dimmer was about £30.

http://www.cutter.com.au/products.php?cat=Cree+XPE