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Another DIY LED fixture


M@rine_lover

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M@rine_lover
Probably makes absolutely no difference.

 

Thanks.

 

Today is the GOOD day to starts my wiring and soldering however I'm still not decide to choose 2 or 3 to work on :angry: !

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I noticed that you haven't given details on what LEDs you are running, what is driving them, and what lenses you are using. Also, what kind of tank is this going over in the end?

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M@rine_lover
Could you post a pic of how you wired and soldered the led's together? Very clean setup!

 

Hi bro,

 

Sorry no picture as I have already screwed the fixture and now on temperature testing.

 

For my wiring, there was nothing special....just drill extra 2 holes for wiring. One to the (+) of star PCB and another for (-) of star PCB out to another (+) of star PCB. All are the same as normal wiring except that I done it behind and hide i :D t.

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M@rine_lover
I noticed that you haven't given details on what LEDs you are running, what is driving them, and what lenses you are using. Also, what kind of tank is this going over in the end?

 

Hi evilc66,

 

Stay tune...I'll do a wrap up soon.

 

Now busy on testing the temperature of the unit.

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Did the acrylic come already cut from DAMA?

 

Thanks for posting your build. You remember that I asked you some questions about your previous build when I saw the picture of it. It is a nice looking build, and I can't wait to hear about the temperature results.

 

Thanks again,

Mark

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M@rine_lover
Did the acrylic come already cut from DAMA?

 

Thanks for posting your build. You remember that I asked you some questions about your previous build when I saw the picture of it. It is a nice looking build, and I can't wait to hear about the temperature results.

 

Thanks again,

Mark

 

The rectangular hole is cut by DAMA and the rest are self drilled.

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M@rine_lover

My new LED fixture design's concept and philosophy :

 

Finally, my new baby was born on 9th August 2009, 2330 after a long process of planning, designing and implementation. My new LED fixture was successfully created and completed with the following concept and philosophy:

 

(1) Slimmest, light, neat and durable

(2) Cost efficient, with high quality & standard

(3) Wide Light spread without spotted effect

(4) Ease of access for repair and maintenance

(5) Scalability for future upgrade(Optional)

 

114.jpg

116.jpg

 

From the series of pictures that I have posted, you can see the whole process of using only White acrylic to box up the entire light as a fixture. I preferred acrylic material as it is very light weight and easy to drill as compared to aluminum, and also have various colors as choices. As for the heat sink, I’m using a 3mm aluminum plate instead of fin heat sink as it looks very bulky and also put on weight which is against my design concept and personal liking. Wires are all hidden and done behind the aluminum plate to have neat outlook.

 

For this project, I have improved the design by reducing the height of 8mm to 6.5mm (slimmer) without affecting the ventilation, added more LEDs includes 4 UV for better area coverage, larger plate size of aluminum sheet to cater for fast heat transfer, 2 fans for air circulation (22 CFM/fan) and last but not least, creating the refreshing design of fixture layout internally & externally by using WHITE acrylic as compared to the 1st LEDs black fixture that I'm using it now.

 

My 1st LED black fixture

DSC00039.jpg

DSC00048.jpg

 

My 1st LED black fixture -Light on

DSC00047.jpg

 

 

Testing

 

I’m going to do 2 reliability tests at the room temperature (28~30 degree) for 3~7 days continuously starting from 12th August 2009. Same as previous project, I’ll be using Fluke Digital Thermometer to take down all the temperature reading as precaution measure. I would also like to take the par reading however I do not have the PAR meter on hand so I have to drop off this idea at the meantime.

 

First test is to run the light set for 16~20 hours continuously with 2 fans running and measure the temperature every one hour interval. If the temperature increases to more than 50 degrees, I may consider add in Fin heat sink and repeat the process again but I doubt it needed.

 

Second test is to run the set for 8~10/16~20 hours without fan but I have to monitor very closely and perform temperature taking every 20~30 minutes as I do not want to “cook” my LEDs and wrap my acrylic. I’m expecting the temperature to rise to 60~70 degrees which is still within the SSC P4 LED specification. Otherwise, Fin heat sink may be considered as “adds-in” and the whole process of testing needs to be repeated. This particular test is meant to create a scenario that in case 2 fans malfunction when I‘m not at home, it will not burn off my LEDs within a period of time.

 

Total output “Kelvin” by visual is estimated to be about 12~14KK.

 

 

Future upgrades (Optional)

 

1.Add DIY programmable dimmer circuit or purchase off-the shelf product to create dawn-and-dusk simulation effect.

2.Add DIY circuit to cutoff the LED when Chiller malfunctions or purchase off-the shelf product.

 

Total Cost and Parts Used (SGD)

 

TotalCost.jpg

 

 

MISC

 

LEDkit.jpg

 

 

Tank Details

 

Mix Reef 2ft cube tank. Corals are birdnest, monti, acro, zoa, blasto, prata, acan, goni .. etc.

Currently there is no fishes but with some inverts.

Equipment: Vortech MP40W & MP20, TLF FR, Arctica 1/10hp powered by AB1000, Eheim 1260 return pump, Schuran JetSkim 120

 

 

Conclusion

 

With my existing 22 LEDs lighting design, although I have no PAR meter to measure the PAR value, ,I can still see the improvement growth of a few of my injured monti, that were previously given by some other fellow reefers, via visual and daily monitoring. My super monti have significantly grown from 1” to 3” within 4 months, with improvement in the coloration (the weak brown monti has gradually changed to its original blue).

 

I preferred LED lighting design as it can help to reduce the heat by more than 50% as compared to MH bulb, and also significantly reduced the total electricity cost by 30~40% per month. Therefore, it helps to sustain my marine hobby which I always love and at the same time promotes ECO conservation.

 

From my past experience and continuous exploration , I have decided to re-build another entirely new and better LED fixture to further promote the growth of the corals in my tank as lighting is one of the essential yet important factor in nurturing healthy marine reefs.

 

With this, I would like to take the opportunity to express my grateful thanks to my wife and 2 obedient children who have been supporting me fully in my project and hobby. And I also like to thank those who have contributed their time in providing advice, comment and feedback to me in making this project a success.

 

Big Thanks !

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Congratulations on the build! It's very clean. I know regular heatsinks most use is bulky for your application but w/ a plate that thin, it can't handle alot of led current. If you're using 2 ELN-60-48D drivers to drive 35 leds, they're going to max out at around 100mA or less. That's probably why you're aluminum plate is sufficient. Just a note, at 100mA, the P4 leds would only give off around 25 lm.

 

Regardless, good work ^^. Keep us posted.

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M@rine_lover
Congratulations on the build! It's very clean. I know regular heatsinks most use is bulky for your application but w/ a plate that thin, it can't handle alot of led current. If you're using 2 ELN-60-48D drivers to drive 35 leds, they're going to max out at around 100mA or less. That's probably why you're aluminum plate is sufficient. Just a note, at 100mA, the P4 leds would only give off around 25 lm.

 

Regardless, good work ^^. Keep us posted.

 

Hi mabviper,

 

Currently, I'm using 1 Meanwell for a string of 13 LEDs and another for 2 string of 11 LEDs(parallel with current mirror cct) which is 1~1.3A and 0.5~065A respectively Even those I may not get 100ml/led but at least 70%, if I am not wrong, unless I have PAR meter to confirm.

 

To my knowledge, current don't drop in serial connection but voltage drop due to load.

 

So how you calculate and get the number of 100ma and 25ml? Pls enlighten me :o !

 

Btw, bro evilc66... I think you are also using ELN-60-48 power supply..right :lol: ?

 

Do you have any comment on what mabviper said B) ?

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I'll need him to clarify how he came up with that number.

 

For your temperature measurements, are you using an infrared or thermocouple type thermometer? If you are using an IR type, where are you taking measurements and are you taking them through the acrylic? Try to measure the die itself, but taking a measurement as close to the star on the heatsink as possible is a good alternative. Using a strip of black electrical tape where you want to take the measurement (assuming an IR thermometer) will offer more acurate results as the reflectiveness of the aluminum will skew the readings.

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M@rine_lover
I'll need him to clarify how he came up with that number.

 

For your temperature measurements, are you using an infrared or thermocouple type thermometer? If you are using an IR type, where are you taking measurements and are you taking them through the acrylic? Try to measure the die itself, but taking a measurement as close to the star on the heatsink as possible is a good alternative. Using a strip of black electrical tape where you want to take the measurement (assuming an IR thermometer) will offer more acurate results as the reflectiveness of the aluminum will skew the readings.

 

yap..I'm measure the die thru' the splash glass by IR type digital thermometer and distance is less than 2.5cm.

 

What do you meant " Using a strip of black electrical tape where you want to take the measurement" ?

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Your measurements will be off if you measure through the plexi. Plexi blocks a reasonable amount of the short wave IR that the thermometers use. Use the electrical tape to get accurate measurements on the heatsink. The bare aluminum will reflect the IR used by the thermometer and make your reading inacurate. The electrical tape is not reflective and will provide a much more accurate temperature. If you are comfortable with the die temps, don't worry about the temp beside the pcb.

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Hi mabviper,

 

Currently, I'm using 1 Meanwell for a string of 13 LEDs and another for 2 string of 11 LEDs(parallel with current mirror cct) which is 1~1.3A and 0.5~065A respectively Even those I may not get 100ml/led but at least 70%, if I am not wrong, unless I have PAR meter to confirm.

 

To my knowledge, current don't drop in serial connection but voltage drop due to load.

 

So how you calculate and get the number of 100ma and 25ml? Pls enlighten me :o !

 

Btw, bro evilc66... I think you are also using ELN-60-48 power supply..right :lol: ?

 

Do you have any comment on what mabviper said B) ?

 

Oh hmm, my mistake. I didn't know you wired it like that. I thought you were driving 17-18 leds per driver in series. Your calculations are accurate, my mistake. If your temperatures work out, I might just adopt a plate instead of a heatsink as well ^^.

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:huh: That didn't make much sense. When you drive LEDs in series, the current is the same and voltage is divided, not the other way around.
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M@rine_lover
Your measurements will be off if you measure through the plexi. Plexi blocks a reasonable amount of the short wave IR that the thermometers use. Use the electrical tape to get accurate measurements on the heatsink. The bare aluminum will reflect the IR used by the thermometer and make your reading inacurate. The electrical tape is not reflective and will provide a much more accurate temperature. If you are comfortable with the die temps, don't worry about the temp beside the pcb.

 

I may want to measure the overall temperature on the heatsink instead of individual die now.

Regards to black tape, is it the normal or special type?

 

Thanks.

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Die temperatures will yeild the most accurate representation of your cooling performance. You will just have to measure it without going through the plexi.

 

The black tape is just regular old electrical tape.

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:huh: That didn't make much sense. When you drive LEDs in series, the current is the same and voltage is divided, not the other way around.

 

When you drive leds, at a constant current, it generates a drop off voltage. The SSC P4s, when driven at 1A, the voltage is around 3.7V. So when you hook them up in series, 18 leds, if you drive the string at 1A, each led will drop 3.7V. Add that up and you'll get 66.6V. However, the drivers can only drive up to 48V at 1A.

 

I'm not sure what the driver will do if you try to drive 18 leds at 1A. It might trip the overload protect and stop working or it might reduce the current of the string to stay below it's operating output voltage. If it does reduce the output current, you're going to get stuck w/ 2.67V/led for 18 leds. That would result in about 100mA for the whole string. I assumed it would lower its output voltage to accomodate for the load but then I might be wrong.

 

Sorry for the confusion ^^.

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He's already answered your question in a reply (see post 38). He's running one driver w/ 13 LEDs and another is running 2 strings of 11 LEDs (w/ a current mirror).

 

Hope that clears things up. :)

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M@rine_lover
When you drive leds, at a constant current, it generates a drop off voltage. The SSC P4s, when driven at 1A, the voltage is around 3.7V. So when you hook them up in series, 18 leds, if you drive the string at 1A, each led will drop 3.7V. Add that up and you'll get 66.6V. However, the drivers can only drive up to 48V at 1A.

 

I'm not sure what the driver will do if you try to drive 18 leds at 1A. It might trip the overload protect and stop working or it might reduce the current of the string to stay below it's operating output voltage. If it does reduce the output current, you're going to get stuck w/ 2.67V/led for 18 leds. That would result in about 100mA for the whole string. I assumed it would lower its output voltage to accomodate for the load but then I might be wrong.

 

Sorry for the confusion ^^.

 

Hi mabviper,

 

Assume 18 LEDs/string driven by 48V, 1A power supply, the current will still maintain at 1A thru' out the string and voltage drop across each LED is 2.67V equal to 2.67Watt/LED. So I dun see why the current drop to 100mA unless you parallel it to 10 string or more lol B) .

 

I think you are confusing us now :o !

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The difference between 100mA and 1000mA in LEDs is usually just 0.1-0.3 volts. i.e. at 3.7v the LEDs might be at 1A (hypothetical, varies between individual LEDs), and at 3.5v it might be only 100mA. Running LEDs specced at 3.7v at 2.67 will get you no output, and possibly damage your driver (depending on the protection mechanism)

So basically nothing at all will happen if there's too many LEDs are in series and the driver will go into some protection mode where everything is just shut off.

 

For an idea of the curve see this: http://myweb.cableone.net/evan9162/creeXRE_Q4/xre_q4-6.png ALL LEDs curves look almost exactly the same. It's just the placement of it (Y-axis) that varies.

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