DIY LEDs - The write-up

[noobtothereef]

He may have had a poor choice in words but the intent was correct. If you compare fixtures of similar intensity, an LED fixture will put less heat into a system than an MH fixture.

but if you did actually use say 1000 watts of mh and 1000 watts of leds the heat would be alot more similar, but the leds are much more efficient and you only need to run 1/3 of the wattage or less to get the same lumens correct?

 

[der_wille_zur_macht]

but if you did actually use say 1000 watts of mh and 1000 watts of leds the heat would be alot more similar, but the leds are much more efficient and you only need to run 1/3 of the wattage or less to get the same lumens correct?

More or less. The first part of your statement is close but a little off. 1000w of LEDs would produce less heat than 1000w of MH - it's just following the laws of physics. When the MH and LEDs each consume 1000w of energy, the LEDs turn more of it into light, which means less gets turned into heat. So it would be "closer" than equivalent fixtures, but the LED fixture would still produce less heat.

But, the second part of your statement is correct - 1000w of (good) LEDs would be vastly more intense than 1000w of MH, so if you were trying to create equivalent fixtures in terms of output, the LED fixture would probably only need 300 - 500w of power. And at that point, it's going to be putting out SIGNIFICANTLY less heat than the 1000w MH rig.

 

[noobtothereef]

More or less. The first part of your statement is close but a little off. 1000w of LEDs would produce less heat than 1000w of MH - it's just following the laws of physics. When the MH and LEDs each consume 1000w of energy, the LEDs turn more of it into light, which means less gets turned into heat. So it would be "closer" than equivalent fixtures, but the LED fixture would still produce less heat.

But, the second part of your statement is correct - 1000w of (good) LEDs would be vastly more intense than 1000w of MH, so if you were trying to create equivalent fixtures in terms of output, the LED fixture would probably only need 300 - 500w of power. And at that point, it's going to be putting out SIGNIFICANTLY less heat than the 1000w MH rig.

like stated above, what keeps someone from using the cheaper led's? i see the lumiscent intesity of the crees is only like 30 or so, theres parahnas with 5500 and are only 70 cents and have tons of different wavelengths and colors, that price is high as its per led, im sure if you bought 200 of them from a big supplier they could be had for less than half that

 

[der_wille_zur_macht]

what keeps someone from using the 10-20 cent leds and just run a ton of them?

Check back a page, I answered that question the first time you asked it. It boils down to three things. The first is efficiency. HP LEDs are more efficient (i.e. cheaper to run) than typical high brightness LEDs.

Let's come up with some examples, using a big tank. If you wanted X amount of light, let's assume you could get that from 200 XR-E Q5 cool white LEDs. That fixture would probably cost you $2000 to build, and it would consume ~500w of power (most people run these at 700mA, which is around 2.5w). To run this fixture for 10 years at 12 cents per kwh (the national average), you'll pay around $200 per year, so $2000 for 10 years. Total cost of ownership, considering build cost and power consumption: $4000.

If we are getting ~80 lumens/watt from this fixture, that's 40,000 lumens.

Typical high brightness LEDs (in 5mm packages) might do 20 lumens/watt. So, to get the same intensity, you'd need ~2,000w of HP LEDs. That's going to cost you around $800 per year in power, or $8,000 for 10 years. Even if the fixture was free it would cost twice as much to actually use it over 10 years.

The second reason why typical high brightness LEDs won't work is thermal management. As I said above, a good HP LED (i.e. Cree XR-E) is designed to allow you to get the heat out in a "nice" and controllable way. Cram a few thousand 5mm LEDs onto a PCB, and you're going to start a fire. Even if you found 5mm LEDs that allowed you to build an equivalent fixture that didn't put out any more heat than HP LEDs, you have no way to manage that heat. So it's going to be a VERY difficult thing to keep the fixture from self destructing.

Thirdly, it's just a matter of density. I think your estimation that 500 cheap LEDs is equivalent to 100 HP LEDs is a little off. An HP LED is just SO much more intense than a typical 5mm high brightness LED that you would have a very difficult time physically fitting enough 5mm LEDs onto a PCB to get the same light density (i.e. output per square inch of fixture.)

If you want to try a fixture with normal LEDs, please by all means do, but IMHO it's going to be a difficult or impossible process to meet the performance and long-term economy of HP LEDs.

 

[der_wille_zur_macht]

like stated above, what keeps someone from using the cheaper led's? i see the lumiscent intesity of the crees is only like 30 or so, theres parahnas with 5500

Can you give a source for those numbers?

The typical Cree XR-E Q5 bin cool white is making 107 lm at it's most efficient (350mA drive current) and ~180 lumens at a typical 700mA drive current. That's an efficiency of ~80 - 90 lumens per watt. I'm not familiar with the "parahna" LEDs you're referencing.

 

[noobtothereef]

http://www.superbrightleds.com/cgi-bin/store/index.cgi?action=DispPage&Page2Disp=/leds.htm#hf5mm

, i read it wrong, its millilumens versus lumens,

there is an 8mm led that is rated at 90 lumens for $1

 

[noobtothereef]

Check back a page, I answered that question the first time you asked it. It boils down to three things. The first is efficiency. HP LEDs are more efficient (i.e. cheaper to run) than typical high brightness LEDs.

Let's come up with some examples, using a big tank. If you wanted X amount of light, let's assume you could get that from 200 XR-E Q5 cool white LEDs. That fixture would probably cost you $2000 to build, and it would consume ~500w of power (most people run these at 700mA, which is around 2.5w). To run this fixture for 10 years at 12 cents per kwh (the national average), you'll pay around $200 per year, so $2000 for 10 years. Total cost of ownership, considering build cost and power consumption: $4000.

If we are getting ~80 lumens/watt from this fixture, that's 40,000 lumens.

Typical high brightness LEDs (in 5mm packages) might do 20 lumens/watt. So, to get the same intensity, you'd need ~2,000w of HP LEDs. That's going to cost you around $800 per year in power, or $8,000 for 10 years. Even if the fixture was free it would cost twice as much to actually use it over 10 years.

The second reason why typical high brightness LEDs won't work is thermal management. As I said above, a good HP LED (i.e. Cree XR-E) is designed to allow you to get the heat out in a "nice" and controllable way. Cram a few thousand 5mm LEDs onto a PCB, and you're going to start a fire. Even if you found 5mm LEDs that allowed you to build an equivalent fixture that didn't put out any more heat than HP LEDs, you have no way to manage that heat. So it's going to be a VERY difficult thing to keep the fixture from self destructing.

Thirdly, it's just a matter of density. I think your estimation that 500 cheap LEDs is equivalent to 100 HP LEDs is a little off. An HP LED is just SO much more intense than a typical 5mm high brightness LED that you would have a very difficult time physically fitting enough 5mm LEDs onto a PCB to get the same light density (i.e. output per square inch of fixture.)

If you want to try a fixture with normal LEDs, please by all means do, but IMHO it's going to be a difficult or impossible process to meet the performance and long-term economy of HP LEDs.

on the taillights i built there were 112 leds withing a 5"x7" space and they didnt self destruct.....in fact they are loacted inside a sealed plastic taillight, they havent melted or shown any signs of it

 

[der_wille_zur_macht]

http://www.superbrightleds.com/cgi-bin/store/index.cgi?action=DispPage&Page2Disp=/leds.htm#hf5mm

, i read it wrong, its millilumens versus lumens,

there is an 8mm led that is rated at 90 lumens for $1

You're off by a factor of 10. 9000 millilumens is 9 lumens.

 

[noobtothereef]

and also if i were to build this, it ouldnt be one giant pcb, it ould be mulitple pcb's whit parts harvested from old computers, each module ould be the size of the computer fan/heatsink, with say 100 leds on each, with 3 colrs, blue, dark blue and white, each on there own circuit, so 3 banks of leds so you can dim each color seperately, the pcb would be glued to heat sink ith non electical conductive epoxy but with high thermal characteristics to dissapate the heat from the pcb to the heat sink, and these "modules could be placed every square foot of the tank, and if anted you could get a 5" optic lens and cover the entire module to project the light evenly, say you only get 20 lumens per led, but you will have 2000 lumens per module

 

[noobtothereef]

You're off by a factor of 10. 9000 millilumens is 9 lumens.

der...... shows how much i know lol

 

[der_wille_zur_macht]

on the taillights i built there were 112 leds withing a 5"x7" space and they didnt self destruct.....in fact they are loacted inside a sealed plastic taillight, they havent melted or shown any signs of it

Then they simply weren't producing as much light per unit of area as a typical DIY LED build for a reef tank.

My fingers are getting a little worn out from this conversation and I fear we are taking the thread off topic. If you want to go your own way, please do. Let us know if it works out.

 

[noobtothereef]

heres something even easier
http://www.superbrightleds.com/cgi-...ge&Page2Disp=/light_bars-flexible.html#Table8

300 leds on a strip ready to install $100

 

[der_wille_zur_macht]

and also if i were to build this, it ouldnt be one giant pcb, it ould be mulitple pcb's whit parts harvested from old computers, each module ould be the size of the computer fan/heatsink, with say 100 leds on each, with 3 colrs, blue, dark blue and white, each on there own circuit, so 3 banks of leds so you can dim each color seperately, the pcb would be glued to heat sink ith non electical conductive epoxy but with high thermal characteristics to dissapate the heat from the pcb to the heat sink, and these "modules could be placed every square foot of the tank, and if anted you could get a 5" optic lens and cover the entire module to project the light evenly, say you only get 20 lumens per led, but you will have 2000 lumens per module

. . . and you'd still be producing less light per $ spent (in electricity costs, which will dwarf the differences in build cost) than using a typical build with HP LEDs. I guess maybe I'm missing something, but do you have an aversion to HP LEDs? They're designed from the ground up to do what we're trying to do. The LEDs you seem interested in simply aren't.

 

[noobtothereef]

Then they simply weren't producing as much light per unit of area as a typical DIY LED build for a reef tank.

My fingers are getting a little worn out from this conversation and I fear we are taking the thread off topic. If you want to go your own way, please do. Let us know if it works out.

10/4, but isnt this called diy led's? maybe i should start a thread called "diy leds but not diy leds"

 

[noobtothereef]

what about these?
http://www.amazon.com/WHITE-LED-Aquarium-corals-light/dp/B002VP07VE/ref=pd_sbs_k_6

5 of these would work....... all for less than $200

 

[der_wille_zur_macht]

heres something even easier
http://www.superbrightleds.com/cgi-...ge&Page2Disp=/light_bars-flexible.html#Table8

300 leds on a strip ready to install $100

Again, those are much less efficient than the typical HP LED. So after a year or two of operation, it'll be a more expensive fixture.

10/4, but isnt this called diy led's? maybe i should start a thread called "diy leds but not diy leds"

You have a point, and forgive me if it came off as trying to get rid of you in this thread. My thought was that this thread has, to date, concentrated on a straightforward, standard build. When people have had ideas off the beaten path, they have typically started another thread. See the various build threads featuring meanwell drivers instead of buckpucks, or DIY drivers, different layouts, etc. That said it's an open forum so post where you wish.

what about these?
http://www.amazon.com/WHITE-LED-Aquarium-corals-light/dp/B002VP07VE/ref=pd_sbs_k_6

5 of these would work....... all for less than $200

See above comments regarding efficiency. Unless a fixture is using very high efficiency LEDs (high bins of Cree XR-E, XP-G, MC-E, XP-E, etc. Or Luxeon Rebels - anything above 90lm/w) it's really not worthwhile, if you consider longterm cost to be important. If you're going to buy a premade panel or strip, or try to DIY a fixture with LEDs other than the typical XR-E or Rebel, I would suggest considering lumens/w and looking for something at or above 90. It may seem like those LEDs are expensive, but after a few years of operation, they'll actually be cheaper. Most of the fixtures and LEDs you're referencing are either way below that, or don't specify reliable numbers, or simply none at all.

 

[mm95z71]

10/4, but isnt this called diy led's? maybe i should start a thread called "diy leds but not diy leds"

I think you should start a thread called "low power sissy led lights". And yes you are getting off topic. I would suggest you use the PM function to have an argument. I'm tired of thumbing through your bickering to find an answer to a question I asked. Make sure you have your numbers correct before you post something and by all means build something and show us how much better it is. I want to see the disappointment on your face. Peace im out.

 

[noobtothereef]

I think you should start a thread called "low power sissy led lights". And yes you are getting off topic. I would suggest you use the PM function to have an argument. I'm tired of thumbing through your bickering to find an answer to a question I asked. Make sure you have your numbers correct before you post something and by all means build something and show us how much better it is. I want to see the disappointment on your face. Peace im out.

mr 18 post, why would i listen to you? im planning my reef build right now and you can follow it in my build thread, im not spouting off anything or trying to go off topic, i never said how much better anything was.... im just considering my options and just like to do something my own way and when somebody says it wont work i try that much harder, im sure the first person that built a diy led reef light also had the same theory, also der_wille_zur_macht has over 9000 posts on this forum and i cant imagine the amount of knowledge he has considering how much i have learned in 100 posts, i am here for information and guidance,...nothing more....

 

[der_wille_zur_macht]

Let's not let this get out of hand and ruin a great thread. If post count was any indication, then we'd be in trouble - I have friends with less than 20 posts on this forum that know more than I ever will about LEDs and fish tanks in general.

noob, if you want to discuss and learn more about non traditional approaches to LED builds, I'd again suggest starting another thread, so people trying to learn about typical builds don't get frustrated by the sudden burst of activity in this thread.

 

[mm95z71]

mr 18 post, why would i listen to you? im planning my reef build right now and you can follow it in my build thread, im not spouting off anything or trying to go off topic, i never said how much better anything was.... im just considering my options and just like to do something my own way and when somebody says it wont work i try that much harder, im sure the first person that built a diy led reef light also had the same theory, also der_wille_zur_macht has over 9000 posts on this forum and i cant imagine the amount of knowledge he has considering how much i have learned in 100 posts, i am here for information and guidance,...nothing more....

You might want to go back and look through Mr. 18's posts. He has actually built an array and tried to teach others how he did it. This is called contributing to the post. You might want to try it some day.