JP's DIY LED Fixture

[jpccusa]

My background: I have no experience with electronics and I am somewhat afraid of electricity. I am a business adm student and full time worker. I'm a DIYer by nature. I decided to do this project so I can have something top of the line, changeable/fixable, and cheaper.

Tank Background: 60W x 24D x 18L Acrylic, live rock and sand, reef-safe fish, mushrooms and Xenias.
My previous lighting was 3 Helios T5 (plug/play type) but I am not longer able to find those for sale.
The wood canopy has a frontal angled lid, which reduces the mounting area for the LEDs to 12 inches.

After a few months of reading and many private messages, this is...

The Plan: 48 Cree LED (60W * 12L / 15 square inches per LED) driven by 2 Meanwells ELN-60-48D, wired in parallel (2 strings of 12 LEDs each driver). Two potentiometers (1 per driver) will control dimming separately for blues and whites for color temperature adjustment (References 1 & 2).

Color: 24 XP-E Royal Blue + 16 XP-G Cool White + 8 XP-G Neutral White + 2 XP-G Warm White

Heatsink: Home Depot has 3/4 U-channels for less than $11/8ft.. I'm aware the LED star is slightly wider, but I don't see a problem with that.

Cooling: Two 120mm fans

Other Parts: - 4 x 1A Quick Blowing Fuses (one per string)
- 4 x 1.0 Ohm, 1% accuracy, 3 or 5W Resistors (one per string)
- 8 x terminal blocks (four per driver)
- 20 gauge pre-tinned wires
- 1 x 10V power supply
- Thermal compound (I have Arctic Cooling MX2 but unsure if that will work)

Please share your opinions. Will this work? Can anything be replaced or improved while keeping the present cost? Is there any mandatory changes that should be done? Etc.

I will try to take pictures of the construction process once it starts.

[katchupoy]

Is that 60L x 18W x 24H tank?

You can also use 1inch square bar $15.00. The idea is more surface area.

How many linear strips will be used?
How many LEDs per strips?

If this the only lights that will be used. Fans are optional. (depends on spacing)

Thermal compound? You will need Thermal Adhesive not Compound? Its a Part A & B that you mix together.

Terminal blocks? I really like this one... compared to the other one...

[TheFishMan65]

Have you seen actual tanks with your color mix? Everyone is different but I like my cool white and royal blue mix. If you do all CW it will be cheaper unless you decide you don't like and then will have to replace them. You may also want to consider changing some of yourCW to RB since the XP-G are brighter than the XP-E. I can't give you advice on the right mix or color, but I can ask question to make you think and hopefully end up happy

Other than that after first read it seems good.

[katchupoy]

So you are doing series/parallel. Are you doing it the safe way? or the risky/fuse way?

[TheFishMan65]

katchupoy,

Why not compound and screws?
I also thought square tubing was a no no because the heat could not escape the inside (unless you blow from the ends).
Do you have a link to those blocks?

[EDIT]
What do you consider the safe way and why are fuses risky?

[kcress]

Yes, a square tube is far worst for cooling than U-Channel. Probably less than half as effective.

Suggestions:
Use these terminal blocks if you want 2-position:
http://search.digikey.com/scripts/Dk...name=A98503-ND

or use these if you want 6 positions:
http://search.digikey.com/scripts/Dk...name=A98507-ND

Use these resistors:
http://search.digikey.com/scripts/Dk...me=UB5C-1.0-ND

Use these fuses:
http://search.digikey.com/scripts/Dk...&name=F2313-ND

[katchupoy]

Aha, I overlooked the screws... my bad.

Square? good point. My argument is that both ends are open, so its not really that they cant escape. Square will have 4 sides of surface area (1 inch per side). More mass? Against 3/4 inch of only 3 sides. Less mass? Just my experience and my opinion.

Blocks. Hmmm i bought it from local radio shack.
http://www.radioshack.com/product/in...ductId=2103231

Safe way or risky (fuse) way. Based on my build thread where the OP linked, I explained to him the + & - of doing series/parallel. And a lot of experts mentioned that it can be done by means of safety fuse, but there is a risk. Now on the last part, I mentioned that if you really want it safe, even without the use of fuse, then you can do it in a certain way. Thats why I asked him, which direction is he going to go.

[katchupoy]

Originally Posted by kcress

Yes, a square tube is far worst for cooling than U-Channel. Probably less than half as effective.

Maybe because of the surface area exposed to air? And since I have 4 sides (square) the U channel has 6 sides exposed to air? Good point....

What temp (without fan) should we see with these HP LEDs at normal (safe) operating temp?

[jpccusa]

Originally Posted by katchupoy

Is that 60L x 18W x 24H tank?

Yes

Originally Posted by katchupoy

How many linear strips will be used?
How many LEDs per strips?

4 strips of 12 LEDs each.

Originally Posted by TheFishMan65

Have you seen actual tanks with your color mix? Everyone is different but I like my cool white and royal blue mix. If you do all CW it will be cheaper unless you decide you don't like and then will have to replace them. You may also want to consider changing some of yourCW to RB since the XP-G are brighter than the XP-E. I can't give you advice on the right mix or color, but I can ask question to make you think and hopefully end up happy

Other than that after first read it seems good.

I have been reading the emperor's got no clothes thread...
I also PMed a few members about color aesthetics (I like shallow water/less blue look).
I have not yet seen pictures of tanks with the mixture I am planning. That would actually be awesome!
I really appreciate your questions and input... Now you are making me rethink the number of RB's.

Originally Posted by kcress

Suggestions:
Use these terminal blocks if you want 2-position:
http://search.digikey.com/scripts/Dk...name=A98503-ND

or use these if you want 6 positions:
http://search.digikey.com/scripts/Dk...name=A98507-ND

Use these resistors:
http://search.digikey.com/scripts/Dk...me=UB5C-1.0-ND

Use these fuses:
http://search.digikey.com/scripts/Dk...&name=F2313-ND

You're a life saver

Originally Posted by katchupoy

So you are doing series/parallel. Are you doing it the safe way? or the risky/fuse way?

Originally Posted by katchupoy

Safe way or risky (fuse) way. Based on my build thread where the OP linked, I explained to him the + & - of doing series/parallel. And a lot of experts mentioned that it can be done by means of safety fuse, but there is a risk. Now on the last part, I mentioned that if you really want it safe, even without the use of fuse, then you can do it in a certain way. Thats why I asked him, which direction is he going to go.

I am doing the fuse way, which based on what I understand is pretty safe.

Please correct me if I'm wrong, but in case something goes wrong (1 blown LED), the only thing it would happen is the fuse would blow up (<$1 loss), stopping the excess of electricity to burn all the rest of LED's, right?

Why do you call this method risky?

[katchupoy]

Using risky on my part is inappropriate use of word. My bad. Maybe also not fully understanding it well.

Kcress? If you have 2 string of 12 leds in series connected in parallel, what will happen to the string if one led goes bad? Will it die "closed"? meaning the rest of the series will still have power or "open"? meaning that the continuity will be broken thus no more light for that particular set of 12 leds.

[jpccusa]

Another question would be why doesn't everyone do the parallel setup in order to save space and money with the drivers? Is it only because it requires much more "tweaking" in order to have the strings balanced?

[kcress]

Tubing doesn't work as well for a few reasons. One is that more mass is not better because this is a steady state situation. If these were flash LEDs then mass would be everything. Energy could be dumped into a mass with low temperature rise. Then the heat could dissipate over time to the environment. But since our application is one that runs for more than a few minutes at a time, it switches to surface area being the important variable.

A bunch of the heat leaves heat sinks via radiation. Warm things radiate to their colder surroundings. This is direct line-of-sight stuff. The greater the difference the higher the radiation transfer. When you use a square tube the entire inside face can never "see" another surface with a lower temperature. This means radiant cooling is fully blocked by all that inside surface area. This makes the heatsink effectively much smaller. A U channel would've allowed all it's inside surfaces "see" somewhere cooler.

Blowing air through the center is lousy too, because it's pretty hard to actually get air to blow down those tubes. They don't well match any fans and if they do the air gets warm and the "other" end gets the hot air from the first end.

As for parallel. As katchupoy has pointed out, if you're multiple strings end up with a situation where if one is open and ceases carrying current the others are still below their maximums you could probably dispense with fuses. You would notice your lighting was strange and could take action.

If on the other hand if a string opening will immediately over-current the remaining strings it would be better to have the fuse. Most of our LEDs will take an amp for a while without undue stress if the cooling is adequate. That means a 1A fast blow fuse has enough time to open preventing a burn out or a lot of stress to the remaining LEDs.

In reality if you over amp a string, probably one LED will burn-out open and act as a fuse anyway, but I'd rather have a fuse do it. Occasionally LEDs fail shorted like incandescent bulbs that get superdupermegabright for a few seconds after they've actually failed. In that case you could have several LEDs in a string damaged which a fuse should mitigate.

Not paralleling is simpler.
It costs more. It's less efficient. It causes more harmonics. Uses more space. Is heavier. Entails more power cordage. Requires more dimming solution. But it's more straight forward and works. Hence some people choose it. Since our typcial ELN60-48 can reasonably support 2 strings it really makes more cents to add a few bucks of components and do some simple balancing, instead of adding another $30 driver.

[jpccusa]

Following up on this post, here are some pictures I took a few minutes ago

photo.jpg photo(2).jpg photo(3).jpg

I'm actually pretty happy that the inside of the channel is 3/4 inch, meaning the aluminum is 7/8 inch, or 0.875. I think the star will fit just fine!

[katchupoy]

Originally Posted by kcress

Tubing doesn't work as well for a few reasons. One is that more mass is not better because this is a steady state situation. If these were flash LEDs then mass would be everything. Energy could be dumped into a mass with low temperature rise. Then the heat could dissipate over time to the environment. But since our application is one that runs for more than a few minutes at a time, it switches to surface area being the important variable.

A bunch of the heat leaves heat sinks via radiation. Warm things radiate to their colder surroundings. This is direct line-of-sight stuff. The greater the difference the higher the radiation transfer. When you use a square tube the entire inside face can never "see" another surface with a lower temperature. This means radiant cooling is fully blocked by all that inside surface area. This makes the heatsink effectively much smaller. A U channel would've allowed all it's inside surfaces "see" somewhere cooler.

Blowing air through the center is lousy too, because it's pretty hard to actually get air to blow down those tubes. They don't well match any fans and if they do the air gets warm and the "other" end gets the hot air from the first end.

As for parallel. As katchupoy has pointed out, if you're multiple strings end up with a situation where if one is open and ceases carrying current the others are still below their maximums you could probably dispense with fuses. You would notice your lighting was strange and could take action.

If on the other hand if a string opening will immediately over-current the remaining strings it would be better to have the fuse. Most of our LEDs will take an amp for a while without undue stress if the cooling is adequate. That means a 1A fast blow fuse has enough time to open preventing a burn out or a lot of stress to the remaining LEDs.

In reality if you over amp a string, probably one LED will burn-out open and act as a fuse anyway, but I'd rather have a fuse do it. Occasionally LEDs fail shorted like incandescent bulbs that get superdupermegabright for a few seconds after they've actually failed. In that case you could have several LEDs in a string damaged which a fuse should mitigate.

Not paralleling is simpler.
It costs more. It's less efficient. It causes more harmonics. Uses more space. Is heavier. Entails more power cordage. Requires more dimming solution. But it's more straight forward and works. Hence some people choose it. Since our typcial ELN60-48 can reasonably support 2 strings it really makes more cents to add a few bucks of components and do some simple balancing, instead of adding another $30 driver.

Kcress, thank you very much for a very detailed explanation. I learned something new today.

[jpccusa]

Originally Posted by kcress

Not paralleling is simpler.

Just to paraphrase you, the linear design is simpler, right?

Originally Posted by kcress

It costs more. It's less efficient. It causes more harmonics. Uses more space. Is heavier. Entails more power cordage. Requires more dimming solution. But it's more straight forward and works. Hence some people choose it.

In this paragraph you are still referring to the linear (simpler) setup, right?

Originally Posted by kcress

Since our typcial ELN60-48 can reasonably support 2 strings it really makes more cents to add a few bucks of components and do some simple balancing, instead of adding another $30 driver.

Not only one $30 driver, but 2 additional drivers in my case ($60+).

Comparing the efficiency of parallel and linear setups, would I notice any difference in brightness and/or lifespan of the LED's in one vs. the other? Any difference in savings on my electric bill in the long run?

[kcress]

jpccusa; No I am not referring to "linear". Perhaps you have a misunderstanding.

We are referring to a single string verse two or more wired in parallel.

"Linear" refers to the method of current control. Which we aren't discussing..

[jpccusa]

Darn it! I was avoiding jargon at all costs in order to avoid confusion...

Anyhow, when I said "linear" I meant "a single string verse two or more wired in parallel."

[jpccusa]

CORRECTION OF POST #1 (see underlined)

Color: 24 XP-E Royal Blue + 14 XP-G Cool White + 8 XP-G Neutral White + 2 XP-G Warm White

CORRECTION OF POST #15 (see underlined)

Originally Posted by kcress

Not paralleling is simpler.

To paraphrase you, one single string per driver is simpler, right?

Originally Posted by kcress

It costs more. It's less efficient. It causes more harmonics. Uses more space. Is heavier. Entails more power cordage. Requires more dimming solution. But it's more straight forward and works. Hence some people choose it.

In this paragraph you are still referring to one single string (simpler) setup, right?

Originally Posted by kcress

Since our typcial ELN60-48 can reasonably support 2 strings it really makes more cents to add a few bucks of components and do some simple balancing, instead of adding another $30 driver.

Not only one $30 driver, but 2 additional drivers in my case ($60+).

Comparing the efficiency of parallel and single string setups, would I notice any difference in brightness and/or lifespan of the LED's in one versus the other? Any difference in savings on my electric bill in the long run?

[TheFishMan65]

kcress, Question for you. How much should we over rate the resistors? At 1 amp a 1 watt resistor will work, but it will probably get awfully warm. Do we really need 5x (a 5 watt resistor) or is 2 or 3 good?

Believe it or not I am having trouble finding a 1 watt 1% 1 ohm from my usual supplier.

Thanks

[BluScrnOdeth]

Originally Posted by TheFishMan65

kcress, Question for you. How much should we over rate the resistors? At 1 amp a 1 watt resistor will work, but it will probably get awfully warm. Do we really need 5x (a 5 watt resistor) or is 2 or 3 good?

Believe it or not I am having trouble finding a 1 watt 1% 1 ohm from my usual supplier.

Thanks

I usually get my stuff from Newark.com. I'll see if i can get the link of what i exactly ordered. But i bought 500 1ohm resistors for about 10 bucks with shipping. The shipping was more than the product which cost about 3.50.

[BluScrnOdeth]

[QUOTE=jpccusa;18307818]My background: I have no experience with electronics and I am somewhat afraid of electricity. I am a business adm student ........QUOTE]

This is basically what i have done with my system. Except i dont have any "constant current regulation" because i am using a PC power supply for my testing. So far, 5 days and holding strong. LED's are staying cool with the aluminum U bar, 1 ohm resistor, fuse, and a voltage regulator (just a little extra caution). I have 12v system, 4 LEDs parallel and 12 strands in series. I think i said that right.

i have bene given a lot of crap for not using something that regulates the current, but everything seems to be running just fine and i havent found any articles online that present any danger to my array of LEDs.

[kcress]

A 2W is fine a 3W a little better. You can't run 1W thru a one watt or it will fail in months. It will also burn you the instant you touch it. A two watt would last indefinitely and would probably be painful to touch but wouldn't burn you. A 3watt would not probably be painful and would again last indefinitely.

If you're running 0.8W (800mA) thru a one watt rather than 1A it will probably last as long as the LEDs. It will burn you if you touch it for any length of time. In all cases we since we're mounting the resistor up in the air suspended between terminal blocks it will be as cool as it could possibly be in an application.

If you are really hung up about the power aspect you can actually use a 0.1 ohm resistor in the 1/4W rating and it won't get warm. But then you have to always multiply the meter readings by 10 which is often another point of confusion for beginners.

[jpccusa]

Believe me, reading this is already confusing enough (not your fault Kress). LOL

I think a 1.0 Ohm, 1% accuracy, 3W resistor will work for my setup then (I will be running the driver at 600 mA)

[jpccusa]

This video explains more or less my future setup

[jpccusa]

I have questions about the fans I'll be using for cooling the LED's.

I got 2 of these fans

pc-case-fans-4-led-color-01.jpg

Features:

* The fan glows a fantastic Four color, which adds color and style to any PC system.
* PC Case fan.
* Very quiet 17.5 dB(A).
* Four LED, Blue, Green, Red, Yellow.
* Crystal frame and blades.

Technical Data:

* Frame dimension: 120 x 120 x 25mm
* Fan speed: 1200 RPM
* Fan airflow: 38.4 CFM
* Fan air pressure: 1.17 mm H20
* Fan life expectancy: 20000/hrs 25°C
* Bearing type: Sleeve Bearing
* Connector: 4-pin
* Voltage rating: 12V
* Current rating: 0.15 A
* Noise level: 17.5 dB(A)

My questions are:

1) How can I power those fans? I plan on cutting off the 4-pin connectors. Should I use an old 12V cell phone charger? Would I use one charger per fan or can I connect both fans to the same one?

2) What would be the best way to mount them on my canopy? Remember, my canopy has an open back and an angled frontal lid. I cannot install them vertically inside the canopy (not enough height). Options are:
- On the back, blowing air in OR blowing air out, OR one way each (circulation?)
- Inside, horizontally, parallel to the U-channels, blowing air up, down, or one each.