# LED floodlight query



## Quagulator (May 4, 2015)

5700 K is fine, I use 2 x 15w on a 5.5 gal. High tech at one point, now low tech. They work, but loose efficiency rather quickly. Expect to replace them at some point sooner rather than later


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## jollos (May 27, 2015)

Quagulator said:


> 5700 K is fine, I use 2 x 15w on a 5.5 gal. High tech at one point, now low tech. They work, but loose efficiency rather quickly. Expect to replace them at some point sooner rather than later


Damn... I was under the impression that lifetime would be greater than tubes. Coild it be possible that chip quality could be a contributing factor? I have heard a few stories about the cheapy generic branded units off amazon going dim pretty quickly.

I see your wattage closely resembles wattage reccomendations for traditional lighting.. i assumed this would be out the window for led, especially as packaging often states things like "replaces 100w"


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## jeffkrol (Jun 5, 2013)

jollos said:


> Damn... I was under the impression that lifetime would be greater than tubes. Coild it be possible that chip quality could be a contributing factor? I have heard a few stories about the cheapy generic branded units off amazon going dim pretty quickly.
> 
> I see your wattage closely resembles wattage recommendations for traditional lighting.. i assumed this would be out the window for led, especially as packaging often states things like "replaces 100w"



1 LED watt/ 4L.. 


Plenty of 6500k floods, though not part. necessary..
https://www.amazon.com/Biltek-Aquarium-Flood-Light-Lighting/dp/B00CBZ3BGM




Think the biggest problem w/ these is

all the electronics (AC/DC conversion ect) is over the main heat source..


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## jollos (May 27, 2015)

Thanks for the encouragement, i think i will go for 2x 10 watt for the 70 litres which should get me in the ballpark of 1 watt per 4 litres. I will see how they go.. thoughts? Now..i just need to work out how to mount them as nicely as quagulator has mounted his


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## jollos (May 27, 2015)

So...I sat on this for ages trying to engineer an effective and safe way to mount the lights....eventually coming up with as simple but effective method. I ended up going with 2 x 20w for the 70 litres. 

Here is a pic after a week. I ended up deciding that i don't like hair grass and was finding it was taking over... so.. what was a good emersed grown, had big tufts pulled out all over the place.. i am sure it still fill in. The frogbit is currently just to suck as much nurients out, to prevent algae growth. 

In the final image, i grabbed this small leafed stem plant plant yesterday...any ID?


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## Quagulator (May 4, 2015)

Speak of the devil,

I finally had 1 of my 2 x 15w floods go out after 10 months of 8 hours a day. 
Cheap enough for me not to care, I have a backup light for that tank anyway. 


Expect a short life, plan to replace as needed


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## Wobblebonk (Feb 13, 2018)

I'm running a pair of 20w or 15w units over a sump, though only for about the past 3 months. I expect I'll feel the same as quagulator about them when they die... they were cheap.


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## Edward (Apr 11, 2005)

Quagulator said:


> They work, but loose efficiency rather quickly.


 How do you determine that?


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## Quagulator (May 4, 2015)

Edward said:


> How do you determine that?


General experience mostly.... 

output seems to drop off real fast after a few months. Originally they would absolutely blind me and fill the entire room with spill over light, but after a few months they were bearable and the room didn't seem to have the same amount of spill over light. 

They also get really hot, too hot to touch. I can't imagine running them that hot for 8+ hours a day can be good for the components. Definitely not what they were designed for. I Personally would not mount them inside a hood / canopy without adequate fans / ventilation. 

Jeff also mentioned the layout is not ideal.



jeffkrol said:


> Think the biggest problem w/ these is
> 
> all the electronics (AC/DC conversion ect) is over the main heat source..




Case in point... 10 months and 1 had already failed me.


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## Edward (Apr 11, 2005)

Quagulator said:


> General experience mostly....
> 
> output seems to drop off real fast after a few months. Originally they would absolutely blind me and fill the entire room with spill over light, but after a few months they were bearable and the room didn't seem to have the same amount of spill over light.


 I can’t wait for Aquarium LED Lighting Fixtures with build-in PAR controllers. All we get today is PWM (pulse width modulation) controllers mimicking PAR controllers. It is similar to controllers chasing pH mimicking CO2 level controllers.


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## Wobblebonk (Feb 13, 2018)

Edward said:


> I can’t wait for Aquarium LED Lighting Fixtures with build-in PAR controllers. All we get today is PWM (pulse width modulation) controllers mimicking PAR controllers. It is similar to controllers chasing pH mimicking CO2 level controllers.


When they lose brightness over time as they slowly burn out from heat, I don't understand how this would work exactly besides if it had its own par meter that you placed where you were trying to hit a target par... people already don't really want to spend even 200 on a light most of the time, would probably require extensive data on each individual diode/bin to not use a meter and then if it were a high par target would burn out faster and faster as it had to jack up v/a as it started to lose efficiency. Just seems like it would be really expensive to implement for what fw light people want to pay. That would be an awful lot of work... and would still be a pwm controller heh


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## jeffkrol (Jun 5, 2013)

A $20 LUX meter will tell you when it's getting dimmer....
No need to go "in tank" even...


"PAR" and PWM dimming is, currently (were screwing that up in another thread) fairly linear in relationship.

50% duty cycle is 1/2 PAR..

The PAR controller is interesting but like calibrating a sound field.. Lots of data points, modeled changes vs power..
Simplistic way is input a beginning PAR # (average or spot?)and subtract dimming.. Re-calibrate every month or so..

LED's do "create" electricity w/ photons (reverse of what we do) so a tank bottom composed of leds(photo-sensor mode, or use photo-sensors) would work. but...
why? 

Hmmm.. could actually incorporate down looking photo-detectors in the light head..
Actually that would be relatively simple and cheap.. hmm...
Like light sonar.. 
Technology like that is being incorporated in current LED's That smarty lighting thing..

come to think about it, it's pretty doable today..
Measure tank bottom albedo..
can see issues w/ a turbulent surface though..

Oh and really woudn't need full blown "par" sensors on board though would for a calibration..
Save that for the ultra expensive version..


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## Edward (Apr 11, 2005)

jeffkrol said:


> A $20 LUX meter will tell you when it's getting dimmer....
> No need to go "in tank" even...


 I want to have the same intensity during its life span, you know, more than few months and I am not necessarily looking for exact PAR values, just stable light intensity.



jeffkrol said:


> "PAR" and PWM dimming is, currently fairly linear in relationship.
> 50% duty cycle is 1/2 PAR..


 It is absolutely not when time is taken in consideration. Today’s 50% PWM does not produce the same PAR few months later. That would be too easy. 



jeffkrol said:


> LED's do "create" electricity w/ photons (reverse of what we do) so a tank bottom composed of leds(photo-sensor mode, or use photo-sensors) would work. but...
> why?


 It is the basic closed loop feedback control system. It is doable with a single light source but difficult with hundred LEDs per fixture. Still, what if there is a sensing LED very close to each emitting LED and shielded from surrounding emitting LEDs then we have the needed feedbacks. Sensing LEDs don’t degrade as emitting do.


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## Wobblebonk (Feb 13, 2018)

what kind of leds are you using where 50% cycle is making a significant output change in only a few months? (LED floodlights I guess?)


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## jeffkrol (Jun 5, 2013)

Maybe just spend the money in keeping them cool.. 









Problem w/ the floods is "ambient" temp (internal). 
Prob degraded power supplies as well.
Oh, and the lens.. 
https://www.google.com/url?sa=t&rct...ntenance.pdf&usg=AOvVaw1M0oDOoyrPOOzrDklnju8n

Well cooled diodes should not "fade" for a long time..
20,000 hours to lose 20% at 45C..
going from 100PAR to 80PAR in over 5 years (10hr/day)
And actually this is being worked on and improved as we speak.. 

Note though that there are problems trying to determine this w/ such long lived light sources..


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## Edward (Apr 11, 2005)

Wobblebonk said:


> what kind of leds are you using where 50% cycle is making a significant output change in only a few months? (LED floodlights I guess?)


 Nothing specific, just asking for a solution to the universal LED lighting fixture problems. Manufactures claim lifespan of millions of hours and give 12 months warranty when in reality the intensity drops in few months and goes all dark in a year or two.


jeffkrol said:


> Maybe just spend the money in keeping them cool..


Your chart is about lifespan in relationship to light intensity and temperature. My goal is to have consistent light energy for the life of the fixture. Not the same thing.


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## jeffkrol (Jun 5, 2013)

Why? If you keep the diodes cool their light energy is consistent over many years..
I don't see a difference.
Now as to electronics.. same issue.. ps's can last a long time cool esp if w/ good capacitors..

People used to talk about tubes the same way.. intensity drops after a year.. but it was proven that PAR does not decrease as fast as "common knowledge" predicted..

Well treated LED's will have the same par after 5 years as they started out with..

now the rest???? 



> lifespan in relationship to light intensity and temperature


and time...

old:
https://www.hennings-miniriff.ch/vortrag-sindelfingen-2013/messungen/verluste-von-led-modulen/


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## Edward (Apr 11, 2005)

jeffkrol said:


> old:
> https://www.hennings-miniriff.ch/vortrag-sindelfingen-2013/messungen/verluste-von-led-modulen/


 At first the article looks interesting but then I find it difficult to interpret. Not only not being written in English but also the idea of comparing PAR of 3 different sources based on 3 different timings of 8, 11 and 23 months. Why not all 3 sources after the same aging time? 

It says: *“After the measurements with the Apogee one also sees that these do not run linearly and thus the modules will very probably reach a life span of approx. 5-6 years.”* 
It says not linear then why displaying “mittelwert” mean value as average and also “verlus pro jahr” loss per year, makes no sense. 

I don’t know how correct the article is but it says: *“Very interesting here has been a measurement where a module has only run at a maximum of 80% in one period, but the same losses have been detected as in 100% operation.” *This may indicate that PAR deteriorates with operating time regardless of PAR output. Really, I don’t take this seriously. 

It says: *“Say in 1 year about 5'100 hours of operation.”* That makes it 14 hours a day for a year. Then it says: *“If I now this approximately 5'000 hours with 6 years of operation high computer I get there about 30'000 operating hours where most manufacturers promise us. On the other hand, the figures of 50,000 hours are rather unrealistic.”* Well, 5000 hours in 6 years is 2 hours and 20 minutes a day and not 14 hours a day. It doesn’t add up.



jeffkrol said:


> Well treated LED's will have the same par after 5 years as they started out with..


 Interesting.


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## jeffkrol (Jun 5, 2013)

Just for fun.. I love posting this..
World Record: LED installation - Longest Continuous Service | PULSAR
It's kind of fluff but fairly impressive nevertheless..

One more data set:











> I was able to par out my Gen 1 TIR along with Gen 2. I have had both of these since their releases and they have treated me well. They are run 9-10 hours a day, 7 days a week in my frag system. Tested with no current or surface agitation. I should also say that I clean them and don't have them too close to the water (9 inches).


http://reefcentral.com/forums/showthread.php?t=2388439&page=2


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