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Thread: Rev 3 LED lighting

  1. #1

    Join Date
    Dec 2009
    Union City, CA, USA

    Rev 3 LED lighting

    So I have started on my third revision of LED lighting for Algae Turf Scrubbers.


    First, why go LED ... again?

    Long term cost is probably the biggest reason.
    Switching a standard SM-100 to LED could save $150 per year in bulbs + electricity.
    And since I need roughly 4X, that is $600 per year. A really big number!
    Normal CFL/T5 needs to be changed every 3-4 months. I always forget.
    LEDs use nice safe 40 Volts around all that salt water.
    No mercury waste.
    Much less heat transfer to the water.


    Other key threads:

    1) Very detailed analysis on LEDs here:
    The middle section has a ton of good detail on spectrum and so on.
    I do not plan to repeat that in this thread.

    2) The big turf scrubber this light is being built for:
    Just as reference.


    What are my three revisions:

    # Rev 1 = Test simple CFL replacement.
    This was really just a quick experiment to see if LED works. It did.
    - 3 x Warm white
    - 2 x Red.
    - All 3W LEDs, but running at 700mA, so 12W total.

    # Rev 2 = Spectrum optimized.
    This was meant as a real engineering analyisis.
    How to create the perfect LED system. It was done with a lot of
    input on one of the big threads here.
    Well, it worked well of course, but honestly, really not that much better
    than the simple one with warm whites. Just a bit less waster power.
    - 8 x Special Deep Red.
    - 4 x Blue
    - 3 x Warm white.
    - All 3W LEDs, but running at 700mA, so 35W total.

    # New Rev 3 = A lot bigger
    This is meant for a log bigger tank. 250 Gallons.
    - 20 x Cheap Warm White
    - 16 x Cheap Red
    - 8 x Special Deep Red
    - 4 x Blue
    - All 3W LEDs, but running at 700mA, so 110W total.


    What have I learned over the various revisions:

    # LED Intensity / Wattage:
    LEDs are pretty powerful. My REV-2 can easily burn the algae if
    I run them too long / day. I am down to less than 12 hours/day on that one.
    I don't really have a ton of data of course, but from my experience,
    and looking at others on line:
    * Moderate filtering = 0.25 actual LED watts
    * Strong filtering = 0.5 actual LED watts
    So basically 2X the efficiency of a good T5 system.
    And thus probably 4X the efficiency of a standard CFL bulb system.

    # LED Spectrum:
    Clearly, LEDs like the Blue end and Red end of the spectrum.
    Deep Red (Not standard red), and blue seem to really hit it well.
    But unfortunately, simple colored LEDs have a tight spectrum,
    so it also really helps to have some warm whites to hit missed areas.
    Ideal seems to be N * (2 Deep Red + 1 Blue + 1 Warm white)
    FYI : Warm white is really blue + a wide spectrum in the red/yellow/orange.
    All that said, it does not really seem to matter all that much.
    People have had complete success with all warm-white, basic red+blue,
    and various other mixes.
    So while the Ideal may be great, it is probably not worth the extra cost.

    # Cheap Ebay LEDs from China change the game.
    You can get warm whites and reds from Ebay at less than $2 each.
    And these are decent 150lm LEDs.
    If they fail, cheap enough to buy spares.
    But they do not have the deep reds or other fancy ones.

    # LED types:
    The sweet spot seems to be 3W LEDs, run at 700 mA, so 2.3 W.
    These have really high efficiency and longevity.
    Running them below rating helps that even more.
    Going larger than 3W leads to thermal and light distribution problems.
    Too much liht and heat in a single small spot.
    LEDs smaller than 3W are a lot lower efficiency, higher cost / luminance,
    and mean a ton of assembly and soldering.


    So why my exact choices?

    First, the obvious:
    - 8 x Special Deep Red
    - 4 x Blue
    I already have these, and I know they work well, so I am simply moving them
    from my Rev-2 to Rev-3.

    Now for the others:
    - 20 x Cheap Warm White
    - 16 x Cheap Red
    I know from Rev-1 that warm white + red work well.
    And I also have a bit of the blue and deep red already covered.
    But most importantly, these were really cheap on ebay.
    Those 20 warm whites were only $50, which included shipping.
    And supposefly 150 Lumens, so pretty decent quality.
    (Of course, ebay from china ... hard to say)
    But I have looked at them, and they do work, and look fairly bright.


    Lots of details to follow.
    Yes, drawings, pics, and eventually results. I promise.
    But probably rather slowly.
    Big new tank, and SO many things to do.

  2. #2

    Join Date
    Dec 2009
    Union City, CA, USA

    Re: Rev 3 LED lighting


    8 X DEEP RED : LedEngin LZ1-00R205[list] Running at 700 mA
    Luminance not specified. About 400 mW of radiant flux at 700mA
    About 2.9 Vf at 700mA
    1500mA max
    Cost (Newark) = $10 ea
    655-670 nm[/list]
    4 x BLUE : LedEngin LZ1-00B205[list] Running at 700 mA
    About 35 lm at 700mA
    About 3.2Vf at 700mA
    1500mA max
    Cost (Newark) = $10.45 ea
    455-475 nm[/list]
    16 x RED : Prolight[list] Running at 700 mA
    About 70 lm at 700mA
    About 3.4Vf at 700mA
    Cost (Ebay) = $1.30 ea[/list]
    20 x WARM WHITE : Who knows?[list] Running at 700 mA
    About 120 lm at 700mA
    About 3.5Vf at 700mA
    Cost (Ebay) = $2.50 ea[/list]
    4 x 700 mA Power Supply[list] MeanWell LPC-35-700
    Direct 120VAC -> Constant current
    700 mA. Fixed.
    85% efficient
    Sealed, IP67
    Cost (rapidled) = $16.00 ea[/list]
    ## LIGHT SET:

    There are two identical turf scrubbers.
    Each turf scrubber is two sided.
    So there are 4 light sets to build.

    Each set:
    - 2 x deep red
    - 1 x blue
    - 4 x red
    - 5 x warm white
    - 1 x Power suppy.
    - 1 x aluminum plate
    - 10 x small heat sinks
    - 1 x large heat sink
    - 1 x Wood Box for standoff
    - 1 x Diamond diffusion panel for light spreading
    - Wires, screws, white paint, etc

    ## POWER:

    8 x Deep Red = 16W
    4 x Blue = 9W
    16 x Red = 38W
    20 x Warm White = 49W

    Total = 112 Watts
    Each set = 28 Watts, so nicely under 35W per supply.

    With power supply inneficiency, expect 130W at wall.

    Assuming 14 hours per day, = 1.8 KWH/day = 664.3 KWh/yr
    At $0.26 / Kwh (CA,med) = $173 per year in electricity

  3. #3

    Join Date
    Jan 2010

    Re: Rev 3 LED lighting

    Thanks for the right up.

    You mentioned that the 10 watt (cheap warm white ebay led) would be to much light in any one area.

    They work quite well for me and the large tabs are 10 times easier to solder than the 3 watt star pads

    This is directly under my setup of (1) 10 watt warm white and (1)10 watt red (cheap ebay) and (5) rebel cool white, (1) rebel red


    The top part of the screen, which looks a little thicker, is the part under the (2) 10 watt led.

    I hate to say it but the side with the (5) rebel cool white, (1) rebel red, and (2) 10 watt led does better than the expensive setup side.

    I went overboard with the power on the expensive side i.e. 108 watts in a 6" X 10" area. Still adjusting.

    Just my two cents and I hope it helps.

    Good luck with the build.
    Attached Images Attached Images

  4. #4

    Join Date
    Dec 2009
    Union City, CA, USA

    Re: Rev 3 LED lighting

    Ok, I definitely have to agree that the larger 10W ones can work.
    Interesting that they are easier to solder. And of course, less of them to do.


    Interesting that you have cool white. What is that for? Extra blue?

    Amusing note on that:
    I intend to try lots of blue in one section on mine, in the real hope that the algae dies. :?:
    First, I need to steal one of the Red/Blue/Red modules from my current ATS to build and test the new one.
    Second, I want to try one of the main tank LED modules out on the ATS. It is 2 x Cool white, 1 x Royal blue, 1 x Blue.
    My hope is that the algae will not do well under that.
    I have plenty of screen area, so no big deal if a bit dies.


    108 Wats on a 6 x 10 Area??? Holy Crud.
    I was planning on only 28 watts, for a 10x17 area. About what I have now.
    That might explain why the cheap area is doing better.
    What is the wattage on the cheap area? Seems like 38 or so, if running full power.


  5. #5

    Join Date
    Jan 2010

    Re: Rev 3 LED lighting

    "Interesting that you have cool white. What is that for? Extra blue?"

    When I first started the project I wasn't so knowledgeable on what the ideal K would be for algae i.e. (3000k) most grow lights are in the 5000+K region.

    In fact when I first started scrubbing, say 15 years ago, CFL 5000K bulbs were what I used with great success.

    The rebel LED that I got were the newest ones and are quite bright, efficient, and long-lived. (they do seem to work albeit with other colored LED)

    "What is the wattage on the cheap area? Seems like 38 or so, if running full power."

    I am running (2) Meanwell LPLC-18-700 (17.5 watts apiece)

    I kind of like the idea that I am running the 10 watts LED on the low side i.e. at 700mA or probably like .7mA X 10v= 7 watts apiece.

    Would only think this could prolong the life of the LED and the Meanwell driver and like you said they're cheap.

    You probably have seen the 10 watt led but for the benefit of others.

    If you don't mind me asking which ebay seller did you buy from? ( I have had success with angel.edeal)

    Side note.

    I am sitting on 26 high quality LED (approx. $200 but no drivers yet) and I can't bring myself(lazy) to do the tedious process of soldering, tapping, etc....

    Contemplating this.

    (3) 20 watt LED DC Forward Voltage (VF): 13.5 ~ 15.0 Vdc
    DC Forward Current (IF): 1400mA ~ 1800mA
    $45 total shipped

    With the CEN-60-42 (might need to adjust the current down a tiny bit just to be safe i.e. reaching voltage limit of driver)

    This would be all fairly straight forward, quick, and easy. (under $100)

    Again slightly under powering the led for the sake of longevity.

    Forgive me I do start to write to much about my own project/thoughts on your threads but I do it for the possible benefit for you

    and the others that read your thread. (We both do have the interest in developing the use of LED)

    Good luck with the your build.
    Attached Images Attached Images

  6. #6

    Join Date
    Dec 2009
    Union City, CA, USA

    Re: Rev 3 LED lighting

    Regarding ebay:
    I bought the reds from angel.edeal
    But I bought the warm whites from led-world2007
    Seemed to have better specs, by quite a bit. At 3W: Prolight = 90 lm. These were 150lm. I think Korean.
    In my writeup, I already derated lm to 700mA.
    Both arrived quickly, no issues, no dead ones.

    Have you done any temperature measurements on those bigger LEDs.
    Sure seems like it would be difficult to keep a 20W one really cool without a fan.
    Below spec is easy, but I really like to keep them below 40 C.
    Overkill, but has an impact on efficiency and longevity.

    No problem with posting lots of data to the thread. That is what it is for.

  7. #7

    Join Date
    Jan 2010

    Re: Rev 3 LED lighting


    That is the best I can do.

    The metal piece coming down(temp. probe) fit firmly under the LED tab and against the heat sink i.e. approximates a fairly good heat sink temp.. (waited 2 minutes)

    What the junction temp. for the LED is I have no idea but this measurement could lead to an approximation.

    This temp. (89F) is what I got after taking off the slow moving fan. (couldn't measure the LED in the horizontal position)

    The way I look at if you attach a large Al heat sink(in case the fan fails) and under volt a 12v computer fan (nearly silent) there won't be a problem with heat.

    I got my Al heat sink used off ebay i.e. cheap.

    Hope this helps.

    Side note

    That is my oven temp alarm (Polder)

    I put the probe in the meat

    Set the alarm at a certain temp

    The probe wire strings out from the oven

    The result is a perfect roast.

    Wouldn't cook a roast without it.
    Attached Images Attached Images

  8. #8

    Join Date
    Jan 2010

    Re: Rev 3 LED lighting


    You could add this fact also to the benefits of LED lighting. (especially for cool water tanks)

    LED produce little to no infrared light hence they don't heat up the water going past them.

    Although the need to remove the heat from the heat sink is there it can be removed from the back of the LED(heat sink) and therefore

    the energy/heat won't effect the water temp.

  9. #9

    Join Date
    Dec 2009
    Union City, CA, USA

    Re: Rev 3 LED lighting

    Ok, Leds are glued on, soldered, and up and running.
    I used aluminum-epoxy. Similar performance to silver, but cheaper.
    Epoxying them on took about 15 minutes. Way faster than drill/tap/screw.
    Of course, they are stuck for good.

    Naturally, camera has a big problem taking a picture.
    Attached Images Attached Images

  10. #10

    Join Date
    Dec 2009
    Union City, CA, USA

    Re: Rev 3 LED lighting

    Here is the front side.
    LEDs glued on, soldered in a single chain.

    I measured the chain : 40V almost exactly, at 700mA = 38W.
    To be honest, I am surprised it came out as expected, given variation in LEDs.
    Attached Images Attached Images

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