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Discussion in 'Algae Scrubber DIY' started by Kentth, Nov 13, 2017.

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  1. Kentth

    Kentth New Member

    Looking for a source of led parts to build a set of lights for my scrubber. The scrubber is a SM100. built it quite a few years ago, and it works for what i need. originally used florescent on it, and switched to a couple IP65 from amazon about a year ago. Now all they do is flash. So decided to build my own set of units. Wondering what is a good source? Screen size is 5X12 the IP65 were working great until they decided to start flash. I have not been successful in finding the problem.
    thanks in advance.
  2. Turbo

    Turbo Does not really look like Johnny Carson Staff Member Site Owner Multiple Units! Customer

    Do you have a pic? It is a purchased SM100 with a smaller screen in it, or did you DIY one?
  3. Kentth

    Kentth New Member

    I constructed it myself. the screen size id 5X12.
  4. Turbo

    Turbo Does not really look like Johnny Carson Staff Member Site Owner Multiple Units! Customer

    Ok, the SM100 is a specific model made by Santa Monica, I didn't know if you followed his plans and just scaled it back or what not. Post a pic when you can, the method of construction might dictate what suggestions I make (MakersLED heat sinks are usually a good choice, but might not fit/work)
  5. Kentth

    Kentth New Member

    At the time I made it he had set of drawings for it on his page. Between that and the pictures of it on the web page. I constructed it to fit in my filter area. When I went to the LED, then the one overhanging wing, broke off, so I just removed it. The original construct, the florescent fixtures slip on a track into the unit. So basically I can retrofit it to about anything I configuration I want. When I get home to night I will pull it out of my filter area take some pictures of it.

    Thanks for all your help.
  6. Turbo

    Turbo Does not really look like Johnny Carson Staff Member Site Owner Multiple Units! Customer

    Yeah that whole overhang-wing and slide-out design doesn't work very well with acrylic. Lots of weak points along the top.

    You might have to make a few modifications to be able to use a MakersLED heat sink, but I think that would be the starting point. They have 2 styles now, you should be able to use the low-profile one (black anodized)
  7. Kentth

    Kentth New Member

    Modifications are not an issue. My entire filtration system I have built form acrylic and I am constantly tweaking it. At this point I am wanting to change my lighting completely to LED, so I have been trying to find sources for the parts and educate myself on what it will take to build my own lighting. the scrubber is the first piece to be converted, but eventually I would like to set it up so that all the lighting is controlled by a central controller for all the lights. Hoping to run everything off of a raspberry pi or andrino, that is the other reason to go LED, more control of the lighting cycles. I noticed in some earlier posts, it was mentioned StephensLED as a source, but apparently they are out of business. I have found a couple of other, but they seem to a little proud of their product and pricing.

    Again thanks for your help.
  8. Kentth

    Kentth New Member

    nice looking heat sink. I think I can make that work. thanks for the advice.
  9. Kentth

    Kentth New Member

    Want stand corrected. I must of found a bad link. But I found Steves LED's Welcome to Steves LEDs, LLC.
    Now just have to put the pieces and parts together.
  10. Turbo

    Turbo Does not really look like Johnny Carson Staff Member Site Owner Multiple Units! Customer

  11. Kentth

    Kentth New Member

    Business got in the way (I own my own business also), now I am losing fish. The IP65's, have not figured out how to keep them from flashing, stuck a florescent in place their place, to power scrubber until I can get some good led's going. I know I am greatly under powered.
    Here is what I am planning, and please give me any suggestions or changes that you might suggest.

    LED's from Steves LED. 6 luxeon ES deep red 2 semiLED 420nm Hyper-violet on each side.
    not sure if I need optics on the deep red, guessing 60 degree (figure on ordering 2 extra leds of each)

    Heatsink Markers slim (Steve's does not show this) looking at LED supply for source. 6" long will need 2
    (between this and the regular one figure this will fit better)

    Driver: Leaning towards Meanwell LDD-1000h with LDD Driver Array-2X
    second option Steve's double driver.

    Power supply. If my calculations are correct I am going to need 19.4 volts and 5800 mA. So I need 112.5 Watts? (these may be over kill)
    If that is the case Steve's has a LRS-200-24
    Ledsupply LRS-150-24
    Looks like $132.
    Does it look like I have everything I need? Do you have a better suggestion?
    Do you sell on the led arrears? and if so how much and how quick?

    Again thanks for all your help. I get this done then I am going to concentrate on a new light for the tank.

  12. Turbo

    Turbo Does not really look like Johnny Carson Staff Member Site Owner Multiple Units! Customer

    No optics - they come as 120 degree spread IIRC
    You can use a single $15 Meanwell LPC-35-700 for powering both arrays in series. You can put them in parallel to get 50% output (it becomes a current divider when you parallel 2 identical arrays). You would use parallel mode for the first couple weeks/months.
    I'm not sure where you're coming up with these numbers, might be a math error. Likely with the mA - all those LEDs won't take over 700 mA (that's the Meanwell LPC-35-700, 35W and 700 mA constant current)
    I don't currently.
  13. Turbo

    Turbo Does not really look like Johnny Carson Staff Member Site Owner Multiple Units! Customer

    the LPC-35-700 operates at 700mA through a range of 9V to 48V total voltage drop. So you add up the voltage drop across each LED that you wire in series, and as long as that's between 9 and 48 volts, you can use the LPC-35-700.

    When you take 2 identical strings and put them in parallel with each other, the voltage drop calc only uses one chain, and the current is then split between the two (350mA down each string). Literally, the current is divided between the two, as long as they match - same # and brand of LED, and if possible, same bin (Steve's has stringent binning, so you will get LEDs that are well matched)
  14. Kentth

    Kentth New Member

    it has been a long time since I have calculated values and studied amperage draw. I took the mA of each led and multiplied them times the number of led's giving me 4200 (6 *700) for the red and 1600 (2*800) summed them giving me 5800mA. Looks like I must just take the highest mA.

    I was going to ask about wiring in series or parallel. I normally would wire in parallel so that if I lose an led in the circuit I still have the reset. But it appears most are wiring in series.

    So on the driers, should I go with the meanwell drivers or the steve's led drivers?

    again thanks for all your help.

  15. Turbo

    Turbo Does not really look like Johnny Carson Staff Member Site Owner Multiple Units! Customer

    Ah - you're doing the math wrong. The current is the same through each LED. Think of it like water running through a closed-loop pipe and spinning 10 in-line "fans" embedded in the pipe. If you have 20 GPH of flow through the pipe, and none of the water ever leaves the pipe, you have 20 GPH of flow, not 200 GPH. If you put a 10-way splitter in and had 1 "fan" in each branch then you would only get 2 GPH in each fan.

    The first example is constant current, series strings. 700mA of flow.

    The second example would be a constant current, parallel strings. The 700mA would get split 10 ways.

    You do not want to go with the highest current. Remember, they're all sharing the same "stream". So the Reds are only rated for 700mA, so that is your max. 800mA would blow all your reds immediately.

    99.99% wire in series. Wiring display tank LEDs in parallel strings is advanced, but totally different than what I'm referring to. I'll explain:

    With a DT fixture, you're going for maximum output for minimum cost. This means trying to use a bigger power supply instead of multiple smaller ones. So one power supply might have 3000mA of output current, but your LEDs are only rated for 1000mA. So what some would do is make 3 parallel strings of matched LEDs - in most of these cases, you didn't have to match all the LEDs, you only had to ensure that each entire string of LEDs had roughly the same total voltage drop. As long as the voltage drop across each string was (for instance) 30 volts, then the 3000mA of current would automatically divide equally. But if one LED popped and created a gap in one of the strings, that would mean all 3000mA of current only had 2 pathways to divide across (which is 1500mA per string). This would result in an instantaneous cascade of failure on the other 2 strings. The solution was to insert a quick-blow fuse in all 3 strings, so that if one was lost, the fuses on the remaining 2 would blow, saving all your LEDs.

    Now flip over to the algae scrubber scenario.

    If you take two arrays (strings) of LEDs that are matched and connect them to a 700mA driver in parallel, that's 350mA per string. You are intentionally reducing the current to 50% across each string by putting them in parallel, because you want lower intensity initially. If you remove one string, then the remaining gets all 700mA, and that's just fine because that's what those LEDs are rated for. See the difference? You're not splitting the current up in order to get the maximum across multiple strings, you are splitting up the maximum to get a lower current across multiple strings. No fuses needed.

    You can do this with individual LEDs as well. For instance, my Rev 1 through Rev 3 used arrays with 6 reds and 2 blues (or violets), but I placed the blues/violets in parallel (just with each other) and then put that parallel pair in series with all the red. So each red got 700mA, and then the current split between the two blue/violet LEDs (350mA each).

    I've yet to come across an example of anyone else in the hobby using this technique. Which is why you probably haven't heard about it. Not many people DIY display tank fixtures anymore.
  16. Kentth

    Kentth New Member

    Starting to understand, it has been a long time since I have looked at current flow, voltage drops, etc. The first time I messed with led's was when I took 4 conventional leds (blue 440) wired them in parallel and took a 12 volt power supply (calculator power supply) to power them. Use them for moon lights. Been running for over 10 years not 24/7. I am planning on adding a dimmer on this also, assuming will need this for a little control.

    So what I am going to do is as you did with 1 and 3. wire the 2 blues in parallel first then go to the reds in series. If you see a problem with that let me know.

    As I said, my next thing it to look it, is to build a DT setup. I keep looking at the ready made ones and there are a lot of possibilities out there with all kinds of prices. I really like to do DIY, so figure might as well give that a that a whirl also. The only thing on my setup that I didn't build myself is the tank and the heater. Tank stand, overflow (came up with a new one about 6 months ago), sump, algae scrubber, electrical, building it is all part of the fun of the hobby.

    Again thanks for all your help. Plan on getting everything ordered tonight.

  17. Kentth

    Kentth New Member

    So I have been doing some studying. first of all I was confused, didn't realize that the LPc-35-700 was the power supply and the driver. So I don't need a separate drivers and power supply, that will work. The only thing is I will not be able to dim the unit, but for my first one I can make this work. Just still use my timer. Unless there is a way to dim the unit?

    Correct me where I am wrong. the 2 LED is parallel will pull no voltage, the 6 in series will need 12 volts. the power supply will provide the amount of power needed for circuit, there are no adjustments necessary on the power supply/driver. If those assumptions are true then I would need no resistors for the series circuit but will need a 24 ohm resistor for each of the parallel legs. do I have that figured out correctly?

  18. Kentth

    Kentth New Member

    diagram of what I am planning on doing led_algea.gif
  19. Turbo

    Turbo Does not really look like Johnny Carson Staff Member Site Owner Multiple Units! Customer

    I don't know what you're doing there. This is really simple, there are no resistors needed or anything

    The LEDs in parallel will pull the voltage of one of the LEDs. i.e. the voltage drop across the parallel pair will be identical (it has to be)

    You can use a dimmable Meanwell driver, but you will need a potentiometer and a wall-wart power supply to give you the reference voltage for the potentiometer so that the driver "sees" it
    Drivers - Dimmable Drivers - Page 1 - Rapid LED
    It looks like the ELN-60-27D is at end of life apparently, that's the one I was going to recommend. Rapid has a nano dimmable one on there that comes with a potentiometer for $30 though.

    The other option is the Steve's single dimmable The Single- Dimming LED Driver which comes with a dimming knob for $12 and then I think you need the wall wart power supply (12v) for $5 Power Plug 12V 1.0A
  20. Kentth

    Kentth New Member

    Like I said. I spent all evening, reading up on the physics of this and reintroducing myself to electrical circuits. I came across the resistors in a number of the articles and reference material that I read. Of course most of the information I read did not endorse doing the parallel/serial combination, but a few did, makes sense to me. Some of them referenced the need for resistors, on all circuits based on the voltage being feed to them, but then I noticed the power supply you suggested, apperntly is self adjusts to the voltage necessary for the circuit. Looking at that I assumed that it would then be feeding 12 volts to the circuit, based on the draw of the red leds, and therefore I was going to need the resistors in the circuit of the violets, since they were in parallel off of the 12 volt legs. So glad I don't need them, getting harder and harder to find this kind of stuff in small quantities, I used to use radio shack a lot. I have a friend who is a EE, and was going to run it past him. He gets fascinated by some of my projects, he will be home this weekend. (we are working on a solar cell project for our houses currently).

    The dimmable was the direction I was originally headed, but for this first project, this will work, and then if I want to change the power supply later I always can. Doing it the way I am doing it will give me a good stepping stone. Your picture was basically what I had envisioned, thanks for that.

    Only other question is gauge of wire? Stranded or solid? I am finding suggestion of 20-22 gauge.

    Again, thanks for all your help.


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