DIY LEDs - The write-up

[SpacedCowboy]

der_wille_zur_macht of course I want to hook up LEDs for my fish tank, I just said I know something about plcc 2 LEDs which are using in the cars... and don't know much about LEDs you guys using to build light setups for the tanks.
Looks like I still can cancell my order and get some other LEDs If P7 are not really good for me. Maybe I should try the 10w or 20w LEDs?

Thanks,
mark

I think the 10W (or 20!) ones would probably not be a good match. The more intense the light, the more the light-cone effect becomes an issue. The eye sees differences in light-levels far more easily than it judges absolute light-levels, so unless you're going to have lots of them and blanket the tank with an absolutely enormous amount of light (which I think might be dangerous to your corals), I doubt you'd get what you're after.

I have to ask, why not just do what everyone else is doing ? It works well and it's proven, as well as having all the kinks ironed out. If you were an LED expert, I'd be encouraging you to the hilt to blaze a new trail, but from your post, it sounds like you haven't too much experience in this area...

Having said all that, it's your cash [grin]. Blaze that trail and more power to your elbow (and your LEDs) if you want to, mate And a Happy New Year to you too.

Simon

 

[der_wille_zur_macht]

For an enclosed hood over the tank, do the LED's need to something in front of them, or can they be "open" to the water surface?

Unless they're really high up and/or you're brave, there should be a splash shield of some sort. Acrylic is probably the easiest. It doesn't need to be thick or beefy (thinner is better - less optical loss.) I suppose it's arguable that if you use optics and protect the wiring (solder joints, pads, etc.) then you don't technically NEED a shield, but I see it as reasonable insurance.

der_wille_zur_macht of course I want to hook up LEDs for my fish tank, I just said I know something about plcc 2 LEDs which are using in the cars... and don't know much about LEDs you guys using to build light setups for the tanks.
Looks like I still can cancell my order and get some other LEDs If P7 are not really good for me. Maybe I should try the 10w or 20w LEDs?

Thanks,
mark

Mark,

I agree with spaced - the SSC LEDs might work but present lots of challenges. They create a TON of intensity from a single point, which means it'll be hard to distribute light evenly. They also need a higher drive current than any of the typical drivers can do. Higher even than any of the DIY drivers people are using - so you'd pretty much be on your own there.

Despite all those disadvantages, they really offer no advantages over the LEDs typically used - they're the same or lower efficiency, and cost relatively close to what we're already paying (per unit of output.) Hence, they're not really attractive to me. If you're after efficiency and simplicity, use the LEDs commonly used, or Cree XP-G. If you're after a lot of light from a single star package, use Cree MC-E or 3-up Luxeon Rebels, which are both similar to the SSC LED you're talking about in terms of efficiency and absolute intensity, but run at much more typical drive currents (they run at higher voltages, but that's far more simple to deal with than higher currents.)

 

[enerfin]

so soundwave, how is the growth in your tank over the last 9 months? do you have pictures that might show progression? i noticed some growth in a few pictures and i know the rock work has changed a few times (it looks good now BTW) but the HUGE question is... what about coral growth and color? great thread!!

 

[MK]

I think the 10W (or 20!) ones would probably not be a good match. The more intense the light, the more the light-cone effect becomes an issue. The eye sees differences in light-levels far more easily than it judges absolute light-levels, so unless you're going to have lots of them and blanket the tank with an absolutely enormous amount of light (which I think might be dangerous to your corals), I doubt you'd get what you're after.

I have to ask, why not just do what everyone else is doing ? It works well and it's proven, as well as having all the kinks ironed out. If you were an LED expert, I'd be encouraging you to the hilt to blaze a new trail, but from your post, it sounds like you haven't too much experience in this area...

Having said all that, it's your cash [grin]. Blaze that trail and more power to your elbow (and your LEDs) if you want to, mate And a Happy New Year to you too.

Simon

Simon, I have no corals in my tank because long time ago i got back to my first love, tanganyikan cichlids. Unfortunately i don't found any fun with reef and after 3-4 years i decided swap back to Africans.
My main tank is about 190 gal (6'x24"x25") right now im using two 150W Giessemann NOVA II fixtures plus 80W actynic blue it's almost 400W that's why i want to change something.
Yes, I like strong light + strong wave coming from wavebox (reflections) looks like my fish also like that combination but i'm not happy paying $400 for my coned bills every month.
I'm thinking to install those leds in my NOVA fixtures and see is not much space to do that thats why i was thinking to use stronger leds.

Mark,

I agree with spaced - the SSC LEDs might work but present lots of challenges. They create a TON of intensity from a single point, which means it'll be hard to distribute light evenly. They also need a higher drive current than any of the typical drivers can do. Higher even than any of the DIY drivers people are using - so you'd pretty much be on your own there.

Despite all those disadvantages, they really offer no advantages over the LEDs typically used - they're the same or lower efficiency, and cost relatively close to what we're already paying (per unit of output.) Hence, they're not really attractive to me. If you're after efficiency and simplicity, use the LEDs commonly used, or Cree XP-G. If you're after a lot of light from a single star package, use Cree MC-E or 3-up Luxeon Rebels, which are both similar to the SSC LED you're talking about in terms of efficiency and absolute intensity, but run at much more typical drive currents (they run at higher voltages, but that's far more simple to deal with than higher currents.)

Thank you for pointing me in the right directions, I will check those LEDs.

Thank you guys and best regards,
mark

 

[widmer]

I wonder if someone wants to help estimate something for me-

I would like to get the standard 10" long by 5.375" heatsink from www.heatsinkusa.com which Soundwave introduced us to, and many people seem to be using. I would like to cut it into strips which will accommodate 6 of the Cree LEDs each, and I don't want to rig up any fans. Pretending the "worst case scenario" where all six LEDs are running full blast a 1000 mA, would I have to make the strips any wider than the ~1" stars are?

IE it would be 6 Cree XREs running at 1000 mA on a 1" x 10" strip of this stuff. Would that be fine? I haven't built anything yet so I don't really know how warm they are going to get...

 

[Gomer]

I think you'll need active cooling on that strip size at 1amp since you won't have the heatsink in a good convective orientation.

 

[widmer]

New question:

3 Cree XREs at 1000 mA, on a 1 x 5.375 inch heatsink from heatsinkusa, with the fins running the short direction. Good enough without active cooling?

 

[Gomer]

I wouldn't trust any 1A setup without active cooling unless you had a convective cooling setup (ie, vertical fins). There are some exceptions, but I'l talking about typical extrusion methods DIYers here are using.

The fins don't do nearly as much for you unless you can get air movement. Fans do this in any orientation. Without fans, you need to take advantage of "heat rises" to create a convective flow

This will be useful to you
www.philipslumileds.com/pdfs/AB05.pdf

 

[der_wille_zur_macht]

Gomer, that's a great read. Thanks for posting it.

 

[widmer]

Thanks for your help. Then a related question would be, what are people doing for fans that are dead silent and work on a 24v supply? (a link to one I could simply purchase if I go that direction would be great)

My main reservation is, what if the fan randomly fails one day when you're at work...

 

[L98-Z]

Thanks for your help. Then a related question would be, what are people doing for fans that are dead silent and work on a 24v supply? (a link to one I could simply purchase if I go that direction would be great)

My main reservation is, what if the fan randomly fails one day when you're at work...

I was planning to just pick up a few of computer fans and run a 12 or 24V supply to them. I really don't think the loss of a fan is going to cause major damage. According to one of the recent threads, one person questioned if they were really needed as well as the oversized heatsinks. Worse case you lose some lifespan on the LEDs.

 

[sammy113]

I have a question. I'll be helping a friend to build a LED rig for a 75G SPS tank. We'll be using 72 LEDs driven by 6 Meanwell (P) model. In order to have them all to turn on, not to dim, how many 10V wall warts will need for the 6 meanwells? Can I hook them all to just one 10V supply or is too much for it? For now he will be running them without dimming functions. Just On/Off

 

[der_wille_zur_macht]

At one point, someone posted that they drew 3.3mA. So six of them will still only be ~20mA. I really think you'd be hard pressed to find a wall wart that was rated below such a low current. In other words, you should be totally fine with just one.

 

[sammy113]

Thanks for the quick response dwzm!

 

[widmer]

I wonder if the quality control is good enough in manufacture that two 12 volt PC fans in series would be fine, and/or if it would be a fire hazard if one of them shorted?

 

[der_wille_zur_macht]

widmer, if you're talking about running two 12v fans on a 24v supply in series, it works just fine. I've done it often. The fans are really not sensitive to voltage, and you can even use different voltages to control speed (i.e. use 9v to get slightly slower operation, which typically results in almost as much airflow at lower noise.)

 

[MikeFisher1972]

That's what I was thinking about doing is breaking my tank into 3 sections 2x2 this is for the 235g tank.
the question I have is I was looking and saw people when they use 50/50 that is to much blue and they turn down the blue.

24 LEDs at 700mA is about equivalent to an average 250w MH.
so for a 20k look what should the mix be ?

"If you figure between 10 - 20 square inches per LED"
That is awesome that makes it a lot ezer i think.

"you'll be in the range most people are using - lower numbers being more intense."

Now this is where i got confused lower # more intense is that the ocptic you are talking about?

so if a 2' x 2' is 576sq'' then if I was to use the rule of 1 LED to 10 sqr'' that would be 57 or 58 leds not meet the 72 LEDs to meet the 250w MH.
what do i do just make it 72 leds

assuming i made it 72 is that an = # to how many drivers a typical rig - 700mA drive current would drive

Cree XR-E Q5 cool whites mixed 50/50 with royal blues.
Is what i would like to use.

I also would like the LEDs to be up to 10' off the water no more, so i could put rock in and out of tank with out moving LEDs.
so 40 degrees optic because it is more than a few inches off the water.

so a few questions that i have is.
What driver/power supply to get that is controllable?
If i dont want to put 50/50 and turn down the blue what ratio should i put in.
so i need to get the heat sink and Leds and controllable driver and power supply
Now where do I get all them for my 2' by 2' section?
thank you in advance!!!!

 

[der_wille_zur_macht]

Mike, a few thoughts:

1) When I said "lower numbers being more intense" I meant lower square inches per LED. Near 10 is very intense. If you're up near 20, it'll be less intense. But you're right - lower degree optics also result in more intense light. But they also result in much less spread of light - so it's kind of an endless spiral, given a fixed mounting height. If you use tighter optics, you'll need tighter spacing to prevent "cones of light" which means even MORE intensity. Hence I don't really recommend tighter optics unless the fixture is very high above the water (i.e. several feet). You said 10" above the water - I wouldn't use anything tighter than 60's or 80's that close.

2) Suggesting a specific blend of blues and whites is tough, because different people have different preferences, and different LEDs are different colors. Even among "cool white" XR-E LEDs there can be a HUGE variation in colors. We often talk about getting the Q5 bin. That designates a certain brightness. The LEDs are also binned by color, but sadly many suppliers won't tell you that info, so it's kind of hit or miss. My suggestion would be to get enough parts to build a small test rig (or one of your three panels) and try different ratios. Then get the SAME parts from the SAME supplier and you should get consistent results.

3) You said three 2' x 2' sections on a 235g tank - I'm guessing it's 6' x 2' then? If you are doing three panels, you might want more like 32 LEDs per panel. It'll be hard to get even lighting with less than that over such a big area.

4) Drivers. It depends on a couple factors. Basically, there are two routes: mean well ELN-60-48 drivers, which can plug right into a wall (no DC supply required.) These can be had in a D version that's dimmable with a 0-10v DC signal (i.e. a 10V wall wart and a pot). Or, a P version that's dimmable via PWM (if you have a microcontroller to dim with.) These drivers have an internal trimpot that sets max current - it is VERY IMPORTANT to set this correctly BEFORE firing up LEDs for the first time, because the max setting (1.3A) is high enough to more or less instantly fry the LEDs we typically use. Mean wells can run 12 LEDs each.

The other route is buckpuck drivers, which require a DC power supply. Buckpucks can do 6 LEDs each, and require a 24v supply to do so. They are available dimmable, and require just a pot to dim (they have a reference voltage to "power" the dimming circuit.)

 

[MikeFisher1972]

32 LEDs per panel??
thats not as much as i thought.

A 2' x 2' is 576sq'' then if I was to use the rule of 1 LED to 10 sqr'' that would be only 58 leds
But i would like the look of 3 250w 20k MH on a 235g tank
so i need up to 72 per 2' by 2'heat sink to meet the 250w MH.
what do i do just make it more than 1 LED per inch ?
or am i thinking all wrong?
The tank is 3 feet deep but i do have a lot of rock that i will be moving in to the tank from my two 125g tanks.

ok i dont have a microcontroller to dim with yet.

mean well ELN-60-48 drivers how many led can one drive?
thank you

 

[der_wille_zur_macht]

32 LEDs per panel??
thats not as much as i thought.

A 2' x 2' is 576sq'' then if I was to use the rule of 1 LED to 10 sqr'' that would be only 58 leds

58 LEDs per 2x2 foot section of the tank, MAX - that would be very intense. More than 250w MH.

But i would like the look of 3 250w 20k MH on a 235g tank
so i need up to 72 per 2' by 2'heat sink to meet the 250w MH.
what do i do just make it more than 1 LED per inch ?
or am i thinking all wrong?

Sounds like you're confusing my comments about the entire tank and comments about each 2x2' section, sorry. To duplicate three 250w MH lamps on your tank, I'd stay around 90 - 120 LEDs total (30 - 40 per 2x2' section.)

mean well ELN-60-48 drivers how many led can one drive?
thank you

12 LEDs each.