Diy led

[michael_in_nc]

Ok. How much are the drivers you're using? I thought most of the drivers were in that $80 price range?

 

[FLGirl]

I didn't understand what Michael in nc was saying. And I, personally, like to plan for problems down the road. So when Brassmonkeyballs (BMB) made the suggestion about the fuses I thought that made sense. Protect the rest of the fixture until you can repair the problem.

The LED is a diode. The diode's voltage is V ~ Vt*ln( I / Is ). This means the diode's forward voltage is logarithmically related to the bias current, so a small change in voltage results in a large change in current. So, if you hook a stack of 6 LED's in parallel with 5 more of them, you could easily get a diode stack that is slightly different in forward voltage (variations in Is, the diode's semiconductor properties or parasitic resistances). This can cause a runaway condition over time. If one branch pulls slightly more current, it will get hotter. This activates the other sensitivity. The forward voltage is temperature dependent. So, the hotter is gets, the lower it's forward voltage which means it pulls even more current (more power = more heat) and so on.

This statement however, worries me. Which is why I asked for an example. It would probably have helped if I had quoted it.

And only one wire will go to the positive side of the ballast the rest u will jump between parallel series

I thought I had that understood correctly, thank you.

And as far as the web goes, I trust it a little less every day. I learn more from talking back and forth with people.

I didn't think you were hitting on me. I thought it was very kind of you (and everyone else) to offer to show me your set up. I am trying.

I apologize for being off last night, Mardi Gras and all that.

 

[bucks448]

Ok. How much are the drivers you're using? I thought most of the drivers were in that $80 price range?

The driver used to run 30 LEDs is running about $24, and the driver used to run 80 LEDs is $40.

 

[brassmonkyballs]

Ok. How much are the drivers you're using? I thought most of the drivers were in that $80 price range?

The Meanwell ELN-60-48 is $30. 24-48V, 1.3A...V and I outputs are user adjustable via internal pot. Can be dimmed manually with 1-10v source with the D model and PWM with P model. 30 LEDs if 2 strings in parallel. Very well made and available.....cheaper than China version when considering shipping. Properly labeled rating and output is as advertised and of course all the spec sheets are available so you can see the quality of the power being output, etc. And properly packaged for water resistance. Bottom line is the China driver, while functional should not be compared to this line. Look at BigTs measurement results...the FEDY does not perform as advertised and I have a problem with that...though again, it functions. The Meanwells do exactly as advertised.

If you go through here http://www.meanwell.com/webnet/search/seriessearch.html#led you can see all the various models they make with all spec sheets linked. Wattsupply.com carries the entire line.

 

[brassmonkyballs]

FLGirl...the statement that worries you is what I meant by the potential of cascading failures when I suggested putting 1A fast blow fuses inline for protection.

I didn't understand what Michael in nc was saying. And I, personally, like to plan for problems down the road. So when Brassmonkeyballs (BMB) made the suggestion about the fuses I thought that made sense. Protect the rest of the fixture until you can repair the problem.



This statement however, worries me. Which is why I asked for an example. It would probably have helped if I had quoted it.




I thought I had that understood correctly, thank you.

And as far as the web goes, I trust it a little less every day. I learn more from talking back and forth with people.

I didn't think you were hitting on me. I thought it was very kind of you (and everyone else) to offer to show me your set up. I am trying.

I apologize for being off last night, Mardi Gras and all that.

 

[brassmonkyballs]

For the people who have done the DIY led's, I have a couple questions...

1) Has there been any irregular algae outbreaks since up and running?

2) Are your corals growing faster, slower or the same as your previous lighting?

3) Do certain corals react positively to the lights while others react negatively?


Thanks,
Michael

Been running Crees since April 2010

1) irregular no but the Macro Algae growth is extremely fast

2) I have seen much faster growth on some items, normal on others. Zoa's seem to be responding like crazy. As a test I had a monti cap with purple polyps and broke it in half and put one half under a MH and the other under LEDs and both are fast growers but the one under the LED has outpaced the other.

3) Yes and you'll have to acclimate and move pieces if possible. I had to move a chalice to the sand bend for it to start coloring up. a tri-color acro has lost some of purple in its tips but its growing fine. i attribute this the color mixure. The Crees I'm running are 50-50 mix of white and RB. Changing this out to 60% blue soon as they arrive. As for overall growth the parameters of the tank obviously are just as important but everything seems to respond positively to the LEDs.

 

[michael_in_nc]

I can tell you from running christmas lights that I had a problem this year with lights that were 5 years old.....There was a bad light, and a string of lights was shining brighter than the rest of the lights on that string. I knew it was wrong, and if i had cared, i would have taken the time to fix the problem. Since I didn't, the lights that were shining brighter lasted about 3 evenings before they were done...AND i LEFT THEM DONE

FLGirl, this is exactly what I was talking about. This is the best example. In your case, the Christmas lights burned up because of thermal runaway. As the LED's heat up, the forward voltage drops and that branch begins to pull more current (heat up more and more until the current gets high enough it burns out). The fuse will be a safety net to prevent damage from this, but not prevent the occurance. Once it happens, you'll still have to deal with the wiring problem or replace LED's because of the wiring issue. I wasn't saying it won't work. I was just saying it most likely will cause premature failure of the LED's at some point. It may work for awhile and depending on the batch of LED's you get, the power you're running them at, and so on, the time before any issue will vary greatly.

Sorry to all if I was confusing the issue. I was trying to help out. I would hate to see anyone have issues with the LED's as they add up in cost.

 

[michael_in_nc]

The Meanwell ELN-60-48 is $30. 24-48V, 1.3A...V and I outputs are user adjustable via internal pot. Can be dimmed manually with 1-10v source with the D model and PWM with P model. 30 LEDs if 2 strings in parallel. Very well made and available.....cheaper than China version when considering shipping. Properly labeled rating and output is as advertised and of course all the spec sheets are available so you can see the quality of the power being output, etc. And properly packaged for water resistance. Bottom line is the China driver, while functional should not be compared to this line. Look at BigTs measurement results...the FEDY does not perform as advertised and I have a problem with that...though again, it functions. The Meanwells do exactly as advertised.

If you go through here http://www.meanwell.com/webnet/search/seriessearch.html#led you can see all the various models they make with all spec sheets linked. Wattsupply.com carries the entire line.

Thanks!

 

[brassmonkyballs]

FLGirl, this is exactly what I was talking about. This is the best example. In your case, the Christmas lights burned up because of thermal runaway. As the LED's heat up, the forward voltage drops and that branch begins to pull more current (heat up more and more until the current gets high enough it burns out). The fuse will be a safety net to prevent damage from this, but not prevent the occurance. Once it happens, you'll still have to deal with the wiring problem or replace LED's because of the wiring issue. I wasn't saying it won't work. I was just saying it most likely will cause premature failure of the LED's at some point. It may work for awhile and depending on the batch of LED's you get, the power you're running them at, and so on, the time before any issue will vary greatly.

Sorry to all if I was confusing the issue. I was trying to help out. I would hate to see anyone have issues with the LED's as they add up in cost.

The only thing I ask michael_in_nc is that you look closely at the Meanwell specs and the Cree specs before saying someone will get premature failure. These are close toleranced devices and I do not bellieve there would be a thermal runaway possibility. I don't want anyone panicking due to a purist view. Not to mention empirical data is always the best and this has been 'field tested' for several years now.

 

[GUILLO1]

My friend finally got half of the strings to light up.

 

[michael_in_nc]

The only thing I ask michael_in_nc is that you look closely at the Meanwell specs and the Cree specs before saying someone will get premature failure. These are close toleranced devices and I do not bellieve there would be a thermal runaway possibility. I don't want anyone panicking due to a purist view. Not to mention empirical data is always the best and this has been 'field tested' for several years now.

Ok, so I looked at the Cree datasheet:

Voltage = 3.3v @ 350mA (typical) 3.9v (Max)
Voltage = 3.7v @ 1000mA (typical)

So, you could easily have an LED with a forward voltage of 3.7v @ 350mA. You could also have another typical LED with a forward voltage of 3.7v @ 1000mA. If you hooked these in parallel, driven with a 1.4A source (which is generally the target with these devices), this is about what you would have. This compounds with more LED's stacked in series. You now have one LED burning almost 3x the power as the other one. Over time, this is certainly an issue as your power is not evenly distributed. You will get hot spots.

Again, depending on the fabrication and assembly lots, you may well get batches of LED's that work, and they may work for a long time. However, if the supplier you buy from happens to have stock from two different lots, you may well see sufficient variation to cause a problem either short term or long term.

I'm guessing we will have to agree to disagree. I will not wire my setup this way. If everyone feels comfortable with this, then by all means do it.

 

[josephv]

:bum:

For the people who have done the DIY led's, I have a couple questions...

1) Has there been any irregular algae outbreaks since up and running?

2) Are your corals growing faster, slower or the same as your previous lighting?

3) Do certain corals react positively to the lights while others react negatively?


Thanks,
Michael

I have had mine up and running aprox 3 months time now. Some corals respond better than others but over all it's been all good. I have had to adjust the placement of some of them higher or lower in the tank but that was expected. I have had no algae problems in both the old and new tank. As far as the wireing problems that have been discussed lately I have had no problems nock on wood.

 

[brassmonkyballs]

Ok, so I looked at the Cree datasheet:

Voltage = 3.3v @ 350mA (typical) 3.9v (Max)
Voltage = 3.7v @ 1000mA (typical)

So, you could easily have an LED with a forward voltage of 3.7v @ 350mA. You could also have another typical LED with a forward voltage of 3.7v @ 1000mA. If you hooked these in parallel, driven with a 1.4A source (which is generally the target with these devices), this is about what you would have. This compounds with more LED's stacked in series. You now have one LED burning almost 3x the power as the other one. Over time, this is certainly an issue as your power is not evenly distributed. You will get hot spots.

Again, depending on the fabrication and assembly lots, you may well get batches of LED's that work, and they may work for a long time. However, if the supplier you buy from happens to have stock from two different lots, you may well see sufficient variation to cause a problem either short term or long term.

I'm guessing we will have to agree to disagree. I will not wire my setup this way. If everyone feels comfortable with this, then by all means do it.

Agreed...we disagree. I think citing extremes as 'easily possible' is a bit overboard but hey I could win the lotto too.

Lets not drag this on though I 100% agree with you and never challenge the laws of physics myself. However, I just disagree in application....in your example it will be so noticeable as you will not have to worry about waiting for something to fail...you will know you have a problem immediately by the delta in brightness due to this mismatch. As discussed it only takes very small changes in forward V to see a huge swing in forward I...therefore you won't have to take a measurement with a meter, it will be blatantly obvious to the eye.

I would offer to those wiring in parallel though to ease your concerns that when constructing your array that you wire in a 1A quick blow fuse in line for protection but also a 1 ohm resistor in each string as well. This will allow you to easily measure current through each string by measuring the voltage across the resistor. V=IR so I=V/R therefore whatever voltage you measure across the 1 ohm resistor is equal to the current. FWIW.

 

[reefrubble]

I'm having a heat build up issue with my set up . When the LED fixture was outside of my hood it barely got warm . Now inside the hood it is getting hot . I have three 140 MM fans , mounted in the top center section of my hood , but they are only 500 RPM . They are running from the front to back , and are blowing in . I don't think I am getting enough air flow , so I ordered three new fans . They will be here Today , and they are 140 MM as well , but are 1200 RPM , and rated @ 65.2 cfm . The noise level is 23.2 dBA , so that shouldn't be too bad . I would like some input on mounting the fans . I have had some people say mount the fans blowing in , and some say have them blowing out . Is blowing in better , or blowing out better , and why ?

TIA , Ted

 

[brassmonkyballs]

I'm having a heat build up issue with my set up . When the LED fixture was outside of my hood it barely got warm . Now inside the hood it is getting hot . I have three 140 MM fans , mounted in the top center section of my hood , but they are only 500 RPM . They are running from the front to back , and are blowing in . I don't think I am getting enough air flow , so I ordered three new fans . They will be here Today , and they are 140 MM as well , but are 1200 RPM , and rated @ 65.2 cfm . The noise level is 23.2 dBA , so that shouldn't be too bad . I would like some input on mounting the fans . I have had some people say mount the fans blowing in , and some say have them blowing out . Is blowing in better , or blowing out better , and why ?

TIA , Ted

You need both....in and out. bring cooler air in and push warmer air out. But I'm curious whats the setup? Type and Qty of LEDs,,attachment method, etc. In any case if air can't move and be replenished with outside air the result will be heat...even with LEDs.

 

[josephv]

I hope the new fans help the problem Ted . I have found that the royal blue LEDs run hot so I have wired them 11 to a leg rather than 10 to a leg on dedicated strips. .When mixing them in with the white they should not cause a heat issue. This reduced their operating temp without diminishing their output very much. Also I have my fans blowing inward driving cool dry air across the heat sinks. The imported air exits the back of the tank.

 

[reefrubble]

You need both....in and out. bring cooler air in and push warmer air out. But I'm curious whats the setup? Type and Qty of LEDs,,attachment method, etc. In any case if air can't move and be replenished with outside air the result will be heat...even with LEDs.

Go to post #142 in this thread , and you can see a pic , of the fixture .

Thank you for your input . Ted

 

[reefrubble]

I hope the new fans help the problem Ted . I have found that the royal blue LEDs run hot so I have wired them 11 to a leg rather than 10 to a leg on dedicated strips. .When mixing them in with the white they should not cause a heat issue. This reduced their operating temp without diminishing their output very much. Also I have my fans blowing inward driving cool dry air across the heat sinks. The imported air exits the back of the tank.

Joseph , Thank you for your input . If the new fans don't do the trick , I can still cut sections out of the top of the hood . I don't really want to do that , but that is still an option .

Ted

 

[schudini]

also a 1 ohm resistor in each string as well. This will allow you to easily measure current through each string by measuring the voltage across the resistor. V=IR so I=V/R therefore whatever voltage you measure across the 1 ohm resistor is equal to the current. FWIW.

Just be sure to use a resistor rated for at least 1 watt.

 

[brassmonkyballs]

Just be sure to use a resistor rated for at least 1 watt.

yes good point, preferably 5W.