Led q&a

With the success of our Metal Halide Q&A and our T5 Q&A, I thought it necessary to supply us with a LED Q&A.

With the LED movement gaining ground as the forefront of aquarium lighting it is important to stay on top of new advances. While I do not proclaim myself an expert by any means, myself and a few others can answer most LED questions. So please ask away!

 

great idea Dingo

questions
what can we expect in terms of PAR and PUR from the various LEDs that are now in the hobby?

In your opinion is there a definite front runner in the LED market , in terms of lumens per watt?

is there a mathematical formula/ equation that would help you decide how many LEDS you would need to replicate or improve on the light output of a quality T5?

What is the optimum spacing for hi power LEDS in order to avoid shadowing


theres a few from me, Dingo

Steve

 

For a retrofit, what are the best LED's to use to suplement 10k daylight and actinic?

Whats the best drivers to use?

When you buy Led's how do you determin how many Led's you need to support your reef tank?

 

how do i determin number of led's to tank size, to tank depth, to type of coral?

 

12 Royal Blue Cree XR-E LEDs ran at 40% power is equal to or better than 1 48" ati blue plus bulb w/ reflector.

Cool White Cree XP-G R5 LEDs are slightly better in lumans than White XR-E.

only draw back is that XP-G dont have optics/lenses yet, so without them you'll get 100 degree wide light spread.

I like meanwell drivers over buckpacks, because meanwells can run 12 leds. buckpacks only 6. also buckpacks require adt'l power source, where meanwells just a power cord.

running these leds at 70-80% power will get max par and color. so if you have a 55g-100g 4' long tank. 24-48 leds @ 70-80% power would be good for a reef tank depending on what types of corals your keeping. lenses are available in different sizes 20-40-60-80. smaller the beam the more par you will get at the center of beam, but will have a spotlight effect, if leds are spaced far apart or close to water line.

there's addt'l info in the DIY thread, but anything not covered im sure dingo will be here tonight to enlighten us.

www.rapidled.com has some great kits and info.

 

Do you have any industry testing to support the PAR statement? I'm sure at 0 inches that is true but what about at 20? That would be interesting to see. Also a Lumen is the measurement for a unit of Luminous Flux which is the amount of light that can be perceived by the human eye. Radiant Flux is the total amount of energy emitted by light and. So lumens really mean nothing when it comes to sustaining and growing coral. I've not been able to find solid PAR testing on any of the Cree 3 watters other than a couple DIY builds that have been tested with an Apogee PAR meter.

 

Cree XP-E Cool White 10000K @ a 100%, Cree XP-E Royal Blue 450-465nm


Depends on what you want to do with them. For simplicity the Mean Well drivers are very good. Thanks to Night-Rida for pointing that out. But if I was going to build a fully controllable set up I would go with BuckPucks the dimmable drivers have on board potentiometers eliminating the need for external pot's. I've yet to find a Mean Well dimmable with the on board pot.
I was going to go with the QuadPuck and DMX 6 channel controller for my build but decided I don't really want to put that much work into building an extra case to house the external power supply.

 

I do have limited data on this and I will share it when I get off my iPhone and onto my real computer. Sanjay and I are in the process of building and testing a homemade Cree unit but I cannot say when this will be completed. :/

@Steve: I have some very interesting answers to your questions so once I'm on a real computer later tonight I will be able to go into a lot of detail...

 

only info I've seen on the comparison of 3w Cree LEDs xr-e royal blues is from reefbrites 48" w/ 24 (@ 40% power ) leds light strip. reefbrite claims their 48" put out more par than 2 ati blue plus blubs with reflectors. at what distance I have no clue. maybe someone can give us more info.

reefbrite RB-PM48-5050 Premium Aquatics

 

The meanwells have an internal one... But it's more of a pita to access than it's worth! That's why most people just go with external pots