DIY LEDs - The write-up

[rickb]

rickb; What current? 50% is not a current.

A picture would be MOST helpful.

Here are the pics

I have two enclosures over the tank. Each is 24"x12" and slides out of the box. The box has a fan at the back. The is also an additional space for sliding in a clear piece of 1/8" clear to protect the lights.

So the problem is that it gets hot over 40%-50% (5 volts dim). Can I attach a 2" U channel to the sheet to help cool it, do you think that will work?

 

[tqut]

Here are the pics

I have two enclosures over the tank. Each is 24"x12" and slides out of the box. The box has a fan at the back. The is also an additional space for sliding in a clear piece of 1/8" clear to protect the lights.

So the problem is that it gets hot over 40%-50% (5 volts dim). Can I attach a 2" U channel to the sheet to help cool it, do you think that will work?

Hi rickb,

Are you running those LEDs on buckpuck seeing that you stated 5v dim?
If you are, what are you using to dim the bucks?

I have absolutely no idea how to built a 5v PWM dimmer but I do know how to follow instructions from a diagram, so can you post a circuit diagram of the 5v dwm dimming circuit please?


Thanks

 

[rickb]

Hi rickb,

Are you running those LEDs on buckpuck seeing that you stated 5v dim?
If you are, what are you using to dim the bucks? Can you post a circuit diagram of the 5v dwm dimming circuit please?

Thanks

I'm actually using 8 meanwell D's. When I said 5 volts, I had posted earlier that more than 5 volts (of 10) was getting the fixture too hot.

I'll put up some pics.

I have 2 banks of 4, 1 for each fixture.

In each bank all 4 are wired to a radio shack quick connect.
the 2 blue meanwell and the 2 white meanwell dimming circuits are wired together.


In the first pic I'm holding the quick connect, and my fingers in back are holding the combined dimming circuits for the blue and white.

In the second pic, it is still attached to the fixture and im holding the dimming circuit for that bank.

In the 3rd pic i combined the dim circuits from each bank to the RK

 

[n0rk]

1:1 was too blue? Holy shiat, Im gonna have to buy a lot more whites then! I was told to buy 18 Royal Blues and 6 Whites! Yikes!

To clarify my post - I've come from a planted tank background and live where the natural Sun is much yellower, so I'm used to lower colour temperatures. Also, I went for the bluest bin R5s and Royals I could get, in a 5:4 pairing I found running the blues on 350mA and the whites on 1000mA was the right mix for my tastes, beyond that was too blue and hurt my eyes.

It's all about taste. As DWZM said, get sufficient of both so you can have a play around. Unlike any other form of lighting there's so much room for movement in terms of colour mix and you'll inevitably need to find your own ideal.

 

[kuzamu]

how do you hook up the pc fans? please help.

 

[kuzamu]

how can i hook up 2 of these fans http://www.newegg.ca/Product/Product.aspx?Item=N82E16835185005 to the wall with one outlet?

 

[Neogenocide]

Question to those who have built their lights and have them running. After you changed over, did you notice any of your fish get stressed from the change?

Previous setup was 2 175watt MH Pendants over my 46G bow. I'm running 34 LED's over the tank now, which is much brighter by the way. I had added a flame angel 10 days prior to changing over to my led lights. 2 days after making the change, my flame angel breaks out into what I believe is Ich. The longer the lights were on, the worse he looked, spot wise. So I cut my back on my photo period and he was looking better. This went on for about 7 days and the angel progressed to the point of no visible spots. I increased my light cycle 1 hr per day until I was back to the normal 6 hours of full light. Again today, the angel is showing Ich worse than he has before.

So, can the brighter lighting stress the fish to the point of a Ich outbreak?

Thanks,

Scott

 

[kcress]

how can i hook up 2 of these fans http://www.newegg.ca/Product/Product.aspx?Item=N82E16835185005 to the wall with one outlet?

Get a 12VDC wall wart and wire them up. + to + and - to -.

===================================
rickb; Thanks much for the pics. Your fixture is really not conducive to getting the heat away from your LEDs. A large smooth sheet like that just doesn't cut it. It has only a little more surface area than the stars themselves.

Almost anything would help! If you just want to use a flat sheet you should have a bunch of holes in it between the LEDs. The air should then be forced to move up thru those holes from below. That would cause lots of turbulence and air moving past edges of the the metal and it would take advantage of the turbulence caused by the LEDs themselves.

You could also add heat sinks to the top of the flat sheet. U-channel in the correct direction. You need to get the air ripping across the sheet. I'd run several fans in your case.

You also have avoided my current question. This makes me think you don't know the current. Which makes me think you haven't adjusted the MW maximum current. That is the maximum you can drive your LEDs to with "dimming" set to the max brightness. This means your 50% could be over-driving you LEDs.

 

[rickb]

Get a 12VDC wall wart and wire them up. + to + and - to -.

===================================
rickb; Thanks much for the pics. Your fixture is really not conducive to getting the heat away from your LEDs. A large smooth sheet like that just doesn't cut it. It has only a little more surface area than the stars themselves.

Almost anything would help! If you just want to use a flat sheet you should have a bunch of holes in it between the LEDs. The air should then be forced to move up thru those holes from below. That would cause lots of turbulence and air moving past edges of the the metal and it would take advantage of the turbulence caused by the LEDs themselves.

You could also add heat sinks to the top of the flat sheet. U-channel in the correct direction. You need to get the air ripping across the sheet. I'd run several fans in your case.

You also have avoided my current question. This makes me think you don't know the current. Which makes me think you haven't adjusted the MW maximum current. That is the maximum you can drive your LEDs to with "dimming" set to the max brightness. This means your 50% could be over-driving you LEDs.

I'm not avoiding any question, I'm not sure I follow. How do I adjust the 'MW'? max current? I thought this was done applying 1-10v via the dimming circuit. When I said 50% I mean 5 volts to the dimming circuit?

 

[Reef_Matrix29]

rickb, do you have a volt meter to test the max current of your meanwells? Do your drivers have a current trim knob to adjust it independent of the 1-10v for dimming?

 

[rickb]

rickb, do you have a volt meter to test the max current of your meanwells? Do your drivers have a current trim knob to adjust it independent of the 1-10v for dimming?

There is no knob to adjust the led voltage. I do have a voltmeter, I can test the max when I get home tomorrow. However it was my understanding that hge meanwell regulated the voltage on it's own, which is why you can hook itt up to 1 or 12 LEDs?

 

[Reef_Matrix29]

Voltage yes, but current I believe is very much up to you to adjust. I have the non-dimmable meanwells and while the voltage does adjust based on the number of LEDs connected, the current I adjust with a voltmeter to "dial in" the PAR numbers I want and double check it with a PAR meter. So your assumption is correct about the Voltage, but you should check the current (mA) once you get home to see how high you have the LEDs being pushed. Make more sense now?

 

[der_wille_zur_macht]

Is there any problem if I mix the XP-G R5 and XR-E Q5 in 1 string?

Nope. As long as you keep the current lower than the max of all the LEDs in the string, and the total Vf is within range for the driver.

Also, I got a pic of my two different drivers and like I thought, one is NOT dimmable. Some one said they all are. They just dont have the dimming option. Look at the picture. I havent started even though I got all my stuff because I dont know which way to go about it. 36 LED's on a 8x16 inch piece seems crowded per unit no? Any input on that would be great! Thanks!

The drivers you posted a picture of ARE dimmable. Look at the connections on the right - there's a DIM- and a DIM+. That's where you connect your dimming circuit. Also, if you pop the plastic case off, there's a voltage and current trimpot adjustment inside. Generally you'd leave the voltage pot alone, adjust the current pot to give your desired max output, and then use the external dimming connection to provide a dimming control.

I'm actually using 8 meanwell D's. When I said 5 volts, I had posted earlier that more than 5 volts (of 10) was getting the fixture too hot.

I'm not avoiding any question, I'm not sure I follow. How do I adjust the 'MW'? max current? I thought this was done applying 1-10v via the dimming circuit. When I said 50% I mean 5 volts to the dimming circuit?

As Wesley alluded, the ELN drivers have two internal adjustments. You need to pop the case off to see them. One is for voltage - leave it alone - the other is for current. DO NOT run your LEDs any more until you verify that the current pot is set to a safe value. Put a multimeter in series with your LED string, turn the thing on, and adjust the current trimpot to get the output current you want when your external dimming control is set to the maximum value (10v). THEN put the case back together and use your external dimmer to cut current from that max you set with the pot.

If you never adjusted the internal trimpot, that explains why your LEDs are getting so hot. You're likely driving them way too hard.

 

[rickb]

Voltage yes, but current I believe is very much up to you to adjust. I have the non-dimmable meanwells and while the voltage does adjust based on the number of LEDs connected, the current I adjust with a voltmeter to "dial in" the PAR numbers I want and double check it with a PAR meter. So your assumption is correct about the Voltage, but you should check the current (mA) once you get home to see how high you have the LEDs being pushed. Make more sense now?

thanks, I had not thought to check that. However wouldn't the amps increase with the number of LEDs I have but the voltage remain identical based on the input of the dim circuit.

I dont have a par meter and this is a new setup, how can I gauge how much light is enough/too much?

 

[Reef_Matrix29]

the current doesn't change regardless of the number of LEDS, but the voltage does, someone correct me if i'm wrong. as for your second question, without a PAR meter the only way to "roughly" estimate is through observation of your corals over time. If you use optics also, that will increase the PAR as opposed to without optics, so does the height from the water your fixture is placed and number of LEDs you have (current too). we all have been trying to determine what configuration of these LED arrays will be comparable to a HQI or T5 system, but honestly, without a PAR meter to verify, its all just speculation as everyone's setup will vary in many ways.

My suggestion is to do what I did, breakdown and invest in a PAR meter to be sure. Don't rely on the results of one person, get the numbers for yourself and that way you can adjust as needed and get more hands-on understanding of what's going on with your lighting system.

 

[der_wille_zur_macht]

thanks, I had not thought to check that. However wouldn't the amps increase with the number of LEDs I have but the voltage remain identical based on the input of the dim circuit.

Nope, not quite.

An LED has a VERY STEEP but more or less fixed V/I curve - in other words, if you change voltage, the current will change. If you change current, the voltage will change - it's a fixed relationship, you can't change one without altering the other.

Drivers work by sensing the current on the LED string, and adjusting the voltage up or down to keep the current at some target level. The voltage the driver will need to produce to hit some arbitrary drive current is dependent on the total Vfs of the LEDs in the string for that target current.

So, as you adjust the target current, the driver will produce more or less voltage to get the current in the string to the new target value. As you change the properties of the LED string (i.e. add more or fewer LEDs, change the temperature it operates at, etc.), the driver will produce more or less voltage to keep the current the same.

Note that the current is set independent of the number or type of LEDs. If you set up a driver to provide 700mA, it will ALWAYS provide 700mA, regardless of the number of LEDs you connect to it in series, assuming your LED count doesn't exceed any of the specs for the driver. As you add more LEDs in series, the thing that changes is the voltage the driver will need to produce to hit the target of 700mA current.

HOW you go about adjusting the target current is a bit more complicated, especially with a meanwell ELN because there are basically two methods provided. The intention is that you would use the internal trimpot to set a maximum current for your string, then use the external dimming signal to adjust down from there based on your operational needs (i.e. simulating sunrise, etc.)

I dont have a par meter and this is a new setup, how can I gauge how much light is enough/too much?

Trial and error with your livestock, or just double-check that your LED count, current, optic choice, height above the water, etc. is all relatively close to what other people are using who have the same LEDs as you. There have been enough of these builds now that it should be pretty straightforward to get a rough verification.

 

[rickb]

Thanks for the info guys, I will check it.

 

[crvz]

If you never adjusted the internal trimpot, that explains why your LEDs are getting so hot. You're likely driving them way too hard.

So reading this comment, should I assume that the factory setting of the current trimpot is too much for our intent? I was not planning on adjusting the ELN-60-48D for the 12 LEDs I'm going to use.

 

[der_wille_zur_macht]

I have no information on what to expect from the factory - and the fact that they don't explicitly state that it comes set at some certain value would make me assume it's set "wrong" and hence I'd assume that the setting at least needs to be verified.

The max possible current is likely higher than we want to run LEDs at (even the LEDs that can "stand" 1.3A like the XP-G will run cooler and more efficiently at lower currents, and live longer lives.)

 

[crvz]

And while I'm here, I'll ask another question. If you recall, I'm looking at using LEDs for dawn/dusk supplementation, and here's my current LED layout. 2 white, 4 blue, and 6 royal blue, in hopes of it giving me a ~14kK look. I've got them tentatively laid out like this on the light rack (aluminum tube).

So really 2 questions. First, am I in the right ballpark for color temperature? And 2, this is a 17" square frame that will be centered over a 36" wide tank... does anyone think I'll get inadequate coverage with this approach? I'm concerned about spotlighting, or only getting half the tank covered, so I'm looking for input.