L.E.D. vs HALIDE/T5/VHO

[Ron99]

Eugene is correct. I showed those charts to show how the bulbs we choose for reef applications spike in the same wavelengths as the most efficient ones for coral photosynthesis.

PAR meters measure all light between 400nm and 700nm. However, 500 to 600nm light does not produce as much photosynthesis as light around 450nm or 650nm to 700 nm. So while overall PAR may seem to stay the same or drop somewhat overall PUR (Photosynthetically Usable Radiation as shown in some of the articles you linked to) may drop more than PAR since the decrease in blue is probably more than the decrease in the green to red part of the spectrum. So we should probably look more at PUR than PAR but few people have spectrophotometers that can do the more complex analysis. What is intersting is that if you measure PAR of a cool white LED and compare to a blue LED, they put out very similar PAR numbers. I would be really interested to see what a PAR meter measures for a green LED of similar wattage. I suspect that PAR would be very close to the others but that's not PUR and corals would not do well under pure green LEDs.

MH and florescent bulbs degrade relatively quickly (within 1 to possibly 2 years with the better bulbs) such that PUR decreases as the overall spectral output changes (or shifts depending on your frame of reference) to be more warm. It is fairy well accepted that nuisance algae grow better at warmer colour temperatures and old bulbs can promote their growth, as I have seen first hand with my old T5 bulbs. If things did not change in that way why change bulbs so often? So to summarize, blue decreases a fair bit but green to red increases somewhat so the loss of blue in the PAR is offset somewhat by the increase in green and red. But that does not mean PUR stays the same, it will decrease and the corals will not be photosynthesizing as efficiently.

I still contend that LEDs have a great advantage. A 30% decrease in 50,000 hours means that with a 10 hour a day lighting schedule you could theoretically get 13.5 years of use and PUR will drop 30% in that time. But the CCT will stay the same and you should not have problems with nuisance algae as the LEDs degrade. Realistically, how often do you change your MH bulbs and what do they cost each time? My T5s would realistically last no more than a year and replacement costs were $250 to $300. Let's say the LEDs last 10 years then I am saving $2500 to $3000 in bulb costs. Then add the electricity savings as well as the reduced likelihood of needing a chiller (more an issue with MH than T5) along with the stability of the CCT and LEDs look pretty good.

This whole debate reminds me of the T5s vs. Metal Halide debate. There was great resistance to T5s with people strongly believing that you could not have a thriving SPS tank under T5s and that T5s were inferior to MH (heck, that debate is probably still ongoing). But we now know that is not the case. The same accusations are being leveled at LEDs but I do believe that time will show that LEDs are a very good option for lighting reef tanks.

[sphelps]

Well first realistically you won't get 13.5 or 10 years out of your LEDs as we already agreed. The same unrealistic numbers are given to both halides and T5s and previously discussed. Second how does your bulb and energy savings compare if you have to replace your fixture every six years compared to simply changing bulbs every year?

The other advantage to T5s that people tend to forget is the ability to setup a kind of bulb replacement rotation. Basically only replacing 2 out of 8 bulbs every six months, every time replacing a different set. This keeps your light levels more consistent eliminating the need to lift and lower fixtures and shocking corals. It also means you're only placing half your bulbs every year which saves you significant money in bulb changes.

The most common argument to go with LEDs is to actually save money in the long run which I think you LED guys should stop using and push more on the lower heat and more defined spectrum (if that really is an advantage).

If you're LED fixture costs $2000 and lasts say 6 years and uses around 250W which means it'll cost around $110 per year for power. If you have to replace your fixture every six years then after 10 years (if you keep it that long) it'll have cost you around $5100.

Now if you compare that to say a 500W halide system which can be purchased for around $1000 (equal quality) and will cost around $220 per year to run for power and around $140 per year for bulbs. After 10 years (again if you keep it that long) that adds up to $4600.

Both realistically are comparable in basic cost however neither include premature failure which is possible for both options however the halide system would offer a cheaper fix. Also after 10 years you only have 2 years left on your second LED fixture and if at some point you decided to sell your fixture for whatever reason the halide system will no doubt return a larger percentage of your investment. And I know that you can argue that you build your own fixture so it was cheaper and you can replace LEDs easily and blah blah blah but what about the rest of us who don't want to or can't build such things, I call this the real world as at least 90% of people in the hobby don't want to build there own light fixture.

[Ron99]

Well you make a few assumptions in your financial analysis. I do believe 10 years is a reasonable lifespan even though you disagree. Since nobody has had a decent LED fixture for 10 years yet we can't really tell. So let's look at the 6 year point as an example. The costs you laid out for the LEDs was $2000 purchase price with $110 per year in running costs for a total after 6 years of $2660. The MH was $1000 to purchase + $220 per year in electricity and $140 per year in bulbs for a total of $3160. That is also assuming you don't need to buy and run a chiller which will add a fair bit to the MH costs.

You have also made the assumption that in 6 years if the LEDs need replacing then a fixture will again be $2000 but the costs are likely to come down dramatically by then and you will get a comparable setup for far less money. But you might also be able to simply replace the LEDs by that point and the costs for comparable emitters would likely be less than $200 for say 80 LEDs by that time. There is a big push to incorporate LED technology into mainstream lighting so in 6 years the economies of scale will bring the prices way down. I can already buy generic 3W LEDs with maybe 70% the performance of Crees for $1.50 each (I have some I plan to test soon). In 6 years they will exceed the performance of the current Cree LEDs at or below that cost. You are also assuming that users of MH or florescent lighting use the same fixtures indefinitely. I venture that most people in this hobby change their fixtures at least every 5 or 6 years. Of course some won't and you will find the outliers who have been using the same MH setup for 10 or 15 years but they would be the exception rather than the rule.

I also think it is a false to assume that repairing an LED fixture is more difficult or costly than repairing a faulty MH or T5 fixture. It may or may not be depending on what fails. Replacing an LED is not any more difficult then replacing an end cap or moonlight and replacing a driver should not be any harder then replacing a ballast. If you would feel comfortable repairing a MH or T5 fixture you should be able to do the same with an LED one. If you aren't comfortable then it has to go out for repairs no matter what lighting technology it uses. And MH and florescent ballasts aren't cheap to replace and they do fail over time. So we should leave the failure/repair estimates out of the analysis because there are so many variables there.

[sphelps]

The other day you seemed to agree that 10 years wasn't reasonable, what's changed??

Originally Posted by Ron99

LEDs should last longer because they will only lose some output but not shift in spectrum. So 6+ years is a reasonable estimate for LEDs.

Perhaps changing a ballast is as easy as changing a driver, that's fair enough, but how many drivers are used to drive 250W of LED compared to the number of ballasts for 500W of halide?
How is changing an LED as easy as changing a Halide or T5 bulb? Even the shear number of LEDs to replace in comparison, it wouldn't take much longer to start over. Sorry but if you have to break out a soldering iron it's not that easy. Plus I'd like to talk about actual fixtures not DIY approaches. Like I said let's stay in the real world.

My assumptions were very little, you're assuming way more including price drop when more realistically the LEDs you need to replace down the road will be extinct and difficult to source. You'll have to adapt new types of LEDs into the fixture which will add more complication. Maybe perhaps someone could provide a manual from a supplier of an LED fixture that shows the user how to replace the LEDs? I imagine such thing doesn't exist, for obvious reason.

[superduperwesman]

I say we design LEDs that are easy to replace and make a killing

[OceanicCorals-Eugene-]

Originally Posted by sphelps

The other day you seemed to agree that 10 years wasn't reasonable, what's changed??

Perhaps changing a ballast is as easy as changing a driver, that's fair enough, but how many drivers are used to drive 250W of LED compared to the number of ballasts for 500W of halide?
How is changing an LED as easy as changing a Halide or T5 bulb? Even the shear number of LEDs to replace in comparison, it wouldn't take much longer to start over. Sorry but if you have to break out a soldering iron it's not that easy. Plus I'd like to talk about actual fixtures not DIY approaches. Like I said let's stay in the real world.

My assumptions were very little, you're assuming way more including price drop when more realistically the LEDs you need to replace down the road will be extinct and difficult to source. You'll have to adapt new types of LEDs into the fixture which will add more complication. Maybe perhaps someone could provide a manual from a supplier of an LED fixture that shows the user how to replace the LEDs? I imagine such thing doesn't exist, for obvious reason.

I think it all comes down to the design of any commercial fixture on how easy it is going to fix. Having quick disconnects on parts would allow the plug and play feature you see in most MH systems now. I still remember before when a MH system had multiple components to it before it would work properly. The same would apply here. until a set standard comes out for LED units and connections we are going to see a ton of ways to do it until a "user friendly" way is discovered. We are already seeing this in some of the fixtures coming out, Ron had mentioned the Maxspect fixtures using quick disconnects for there individual emitters (no soldering there). AI has 3 emitter modules (not as efficient but easy to change out)

Regarding the assumption of LED bulb prices droping is not all that off. LED lighting is moving at an incredibly fast pace. In 2000 the cost of a 5mm high intensity white/blue LED would cost $2.00 each from manufactures and now they cost a few cents. No doubt will the same thing happen with high power 3W + LEDs , look at when the luxeons first came out we were looking at manufacture cost of $10 and look at where is it now. LEDs are unique that they are current driven, so even if the specs on newer LEDs change it would be the total forward V and the amount of current taken thats not going to effect the way you pair up LEDs to drivers and should only take a few minutes to figure out how many LEDs can be in an array from simple math.

Originally Posted by superduperwesman

I say we design LEDs that are easy to replace and make a killing

Watch someone is going to put a patent on quick disconnects now that we've mentioned it for LED purposes.

[Ron99]

Originally Posted by superduperwesman

I say we design LEDs that are easy to replace and make a killing

Already being done the Maxspect fixtures are nicely designed in that sense. The individual LED stars are fixed to the heatsink by a couple of screws and the electrical connections are by connectors like computer fans. So to replace them you unscrew the screws, disconnect the wire. screw down the new emitter and reconnect the wiring. A couple of minutes and one screwdriver is probably all you need. Also Bridgelux is developing an interchangeable LED module geared towards home lighting etc. but it could probably be used for aquariums too if it works out.

Originally Posted by sphelps

The other day you seemed to agree that 10 years wasn't reasonable, what's changed??

Perhaps changing a ballast is as easy as changing a driver, that's fair enough, but how many drivers are used to drive 250W of LED compared to the number of ballasts for 500W of halide?
How is changing an LED as easy as changing a Halide or T5 bulb? Even the shear number of LEDs to replace in comparison, it wouldn't take much longer to start over. Sorry but if you have to break out a soldering iron it's not that easy. Plus I'd like to talk about actual fixtures not DIY approaches. Like I said let's stay in the real world.

My assumptions were very little, you're assuming way more including price drop when more realistically the LEDs you need to replace down the road will be extinct and difficult to source. You'll have to adapt new types of LEDs into the fixture which will add more complication. Maybe perhaps someone could provide a manual from a supplier of an LED fixture that shows the user how to replace the LEDs? I imagine such thing doesn't exist, for obvious reason.

I never said that 10 years wasn't reasonable but rather than argue the point I conceded at least 6 years for our modeling of scenarios. Only time will tell what the real lifespan is but given what is known with 40 years of LEDs existence, 10 years is quite possible.

If you keep the junction temperature below 80 degrees C you will have 30% decrease over 50,000 hours. Keeping those temperatures is not hard. The OC spotlights run with heatsinks below 50 degrees and my heatsink is barely warm to the touch (I will try to get accurate temperature readings later). So if we assume degradation is linear then I will have 20% decrease in output/PAR/PUR after 33,333 hours. That is just over 9 years with 10 hours per day of use. Adjust that accordingly depending on your lighting schedule. Light for 8 hours per day and you could see over 11 years with only a 20% decrease. At 12 hours that is over 7.5 years. But if you want to call it 6 years we can do that for now. Let's talk again in six years when I can do some PAR measurements on my fixture

As for changing the LEDs it is all down to the design. See my comments above regarding the MAXspect fixtures. As Eugene mentions, the AI units have 3 emitter modules that are easy to change out and shouldn't break the bank. Here's a teardown of the AI so you can see it:

http://reefbuilders.com/2010/03/31/i...aillumination/

And here's something on the Maxspects where you can see one image of how their LEDs are hooked up:

http://reefbuilders.com/2010/01/22/m...ium-led-light/

Both the above would require the use of a screwdriver to replace the LEDs. Real world enough for you Is it more work then replacing a bulb? Maybe a little but not by much. And using a soldering iron to swap wiring is really not that difficult. If you don't want to deal with that I am sure a repair shop could do it for you fairly inexpensively.

With regards to drivers, they should use multiple drivers. Mine has 8 separate drivers. One failing means replacing one driver at $30 rather than a single ballast at $60 to $150 depending on what type of ballast is used.

[sphelps]

That's good news about fixtures already having ways to easily replace the LEDs, I didn't know they where being made like that yet. Sounds like the MAX fixture is going to be somewhat more economical than the AI as it sounds like it takes a more universal LED replacement where as the AI requires replacement sets that can only be purchased from the manufacture. Ideally a standard should be introduced to all these fixtures for an easy screw in replacement or something so various lighting companies can make replacement LEDs just like metal halide and T5 bulbs.

Basically it seems now my only real concerns are reliability and lifespan. I have extreme doubts that these things will do more than half what they are rated for but I guess time will tell, it's just an awfully long time to wait. I would definitely consider a LED fixture if

• The LEDs could be easily replaced with a somewhat universal LED design (open up competition in the future)
• The fixture was visually appealing (something like the giesemann fixtures)
• Made from quality material like aluminum and did not require fans
• Remote drivers making the fixture light enough to be hung easily from two single points
• Controllable by 0-10V interface
• Minimum 3 year warranty

With all that I would expect to pay between $2000-$3000 and would be happy to do so.

[StirCrazy]

cool, I go away for 3 days and stuff been flying.

the problem is like any other lighting there re going to be good ones and bad ones. good ones will run for 50000 hours with out a problem as they have done there home work and designed a system that runs under 80 C , exotic ones may last longer as they will have super cooled systems that run under 40 or 30C which in all likly hood will give a longer life span as it is basicly heat that is the determanaing factor for the life and intensity drop in LED, they are not effected by water, salt, vibration, ect.. unless the water, salt, ect affects the contact between the heat sink and die, but then heat will go up. but yes there will be the junky brands out there that will last under 6 years.

as for the PAR shift in MH bulbs, there is most definatly a shift and it can be large or it can be small. depends on the bulb its self and the ballast you are driving with. a 10000K bulb will generaly have a lot smaller of a shift than a 20000K bulb, but the that in its self realy means nothing. I have measured a 20000K bulb with a 40% reduction in PAR at 14 months with only a 32% reduction in LUX, so right there it is telling you there is much more than just the intensity lowering the PAR value as if that were the case the PAR and lux values would decrease at the same rate. I have had some 10K bulbs where the LUX decreased faster than the PAR and some the otherway. (an theres were all on the same ballast) so it realy depends on the initial make up and quality of the bulb including which halides and the ratios they use to make there color spectrum, as there are hundereds of different combanations that will give you any givin color.

so back to LED you want to look at longjevity, we can all agree the solaris is a lower end LED fixture, but asside for the odd problems they are going on is it 5th year now (they first came out in 2005 I believe?) with only ballast replacments (the ballasts were garbage ) and the odd LED replacment which is in all likely hood a result of the ballast failing.

Oh and for the record, T5 are infieror to MH

Steve

[StirCrazy]

Originally Posted by sphelps

I would definitely consider a LED fixture if

• The LEDs could be easily replaced with a somewhat universal LED design (open up competition in the future).

thats going to be hard as die's are propritary, but all that being said I guess you could solder any LED to almost any die so who knows.. the easy answer would be to design a holder for the die that attaches to the heat sink. at any rate I understand this one as it is easy on any fixture if you know ho to use a solder gun right now but if you don't..

• Originally Posted by sphelps

  The fixture was visually appealing (something like the giesemann fixtures).

like any other lighting I can see nice ones and ugly retro kits.. you have the ability to have a more sleak looking fixture with these maybe two inches thick

• Originally Posted by sphelps

  Made from quality material like aluminum and did not require fans.

I think they will all still require fans, at least the high end ones, but the difference will be in the size of the fans. a realy good heat sink design will have small almost totaly silent fans that just insure air movment over the fins, where cheaper designed units will have larger fanse and depend on bulk air movment ro remove heat.

• Originally Posted by sphelps

  Remote drivers making the fixture light enough to be hung easily from two single points.

already being done.

• Originally Posted by sphelps

  Controllable by 0-10V interface.

same here, it all depends on the company designer and which ballast he picks. I think some will have intagraded controlers also so they are independant from your other equipment.

• Originally Posted by sphelps

  Minimum 3 year warranty

Originally Posted by sphelps

With all that I would expect to pay between $2000-$3000 and would be happy to do so.

hmm.. If I was making a high end product like this I may concider this but 3 years, as a bumper to bumper wouln't make sence.. how about something like 1 year on ballast wiring, electronics, 4 year on LEDs ?

Steve