Let there be LIGHTS

Discussion in 'The Projects Forum' started by Remy20122, Oct 30, 2014.

  1. Remy20122

    Thread Starter New Member

    Oct 30, 2014
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    I am trying to power 100x3w LEDs. I have an individual driver for each one. How do I power the drivers? Do I need a 12v DC converter, or a larger one? Is voltage drop my biggest concern? If anyone has any answers/ suggestions, it would be appreciated. Thanks.
     
  2. adam555

    Active Member

    Aug 17, 2013
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  3. DickCappels

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    Aug 21, 2008
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    It might help if you post the specifications for your driver, particularly the input requirements.
     
  4. Remy20122

    Thread Starter New Member

    Oct 30, 2014
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    • Input Voltage AC/DC12V
    • Output Current: 650±50mA
    • I just read that if I use a series-parallel, I dont have to worry about voltage drop except in each series.
     
  5. DickCappels

    Moderator

    Aug 21, 2008
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    Good start. What is the maximum output voltage of your driver? What is the forward voltage and current requirement for your LEDs?
     
  6. Remy20122

    Thread Starter New Member

    Oct 30, 2014
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    • I would like to power it with my 12v driver (if possible)
    • the forward voltage of lights are 3.2-3.4v
    • 700mA current requirement for lights
    • each light has an individual driver as well (in addition to the main driver); their input and output voltage is 1v. and current is 600mA
    • here is a rough sketch... Scan0001.jpg
     
  7. DickCappels

    Moderator

    Aug 21, 2008
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    What you have sketched above should work.

    Are you sure your driver can only supply enough voltage for one LED? If you haven't already bought/built/committed one driver for each LED, you might consider putting some LEDs in series on the output of the drivers so as to reduce the number of drivers needed and to raise overall efficiency.

    To answer your earlier question, you would probably be best to buy either one or more regulated 12 power supplies to power all of the drivers, or if you are sure of the voltage range tolerated on the driver input and it really can operate from AC, get an adequate number of hefty line voltage -to- 12 transformers to supply the drivers.
     
  8. Remy20122

    Thread Starter New Member

    Oct 30, 2014
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    I dont think they run on AC, that is why I am going to use the 12v driver to plug into the wall. It has an inverter built in.
    The drivers I have are made to power one 3w LED each.
    Thank you so much for your help. I will send you a pic when it is done.
     
  9. DickCappels

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    Aug 21, 2008
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    Looking forward to the picture!
     
  10. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
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    I sure wouldn't do it that way as you need multiple 12V adapters.
    A single 12V supply needs to be MASSIVE (current rating).. $$$$$$ to do 100LEDs with individual drivers.
    A typical wallwart or black box adapter is NOT going to cut it unless you use multiple ones.

    100 x 3W = 300W.. 300/12 = 25 AMPS (not including safety factor or anything else)

    A better way would be to do multiple series strings of LEDs with each string having its own driver with a higher DC output voltage.

    I would do multiple series strings of 15 (15 x 3.4 = 51V) so an LED driver with an output voltage up to 54VDC would be good.
    A meanwell LPF-40D-54 has a current rating of 760mA and a DC output range of 32-54VDC.
    One LPF for each string of 15 LEDs.
    They also plug directly into the wall and feature the AC/DC conversion and the current limiting all in one package. But its not going to be cheap either.. but you are trying to power 100 high power leds.. cheap is out the window mostly anyways.
    You also gain the ability for dimming via 10V PWM or 1-10V analog or 100k potentiometer if you want. And you will :)

    What exactly are these drivers you intended to use on each LED?.. post a link to the actual product or schematic so we can really inspect it versus the few specs you posted.
    And the same for the 12V power supply.
     
  11. Remy20122

    Thread Starter New Member

    Oct 30, 2014
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    here is the individual driver link. http://www.aliexpress.com/item/10pc...p-drive-1pcs-3W-MR16-Free/2048141083.html?s=p

    I used this 12v driver on my last project (although it was with an LED light-strip) http://www.amazon.com/HitLights-Supply-Driver-Transformer-Output/dp/B00BPCL0MY/ref=pd_sim_hi_1

    I thought strings of 3 LEDs would use approx. 12 volts in each string. If I connect 33 of those in parallel, then all the lights share the same current. And since each light has its own power driver then the lights will illuminate.

    So, I just need to power the drivers, not the lights. However, I do feel like Im leaving something out of the equation.


    I dont mind if the products are expensive, I just want this light to work.
     
  12. BobTPH

    Active Member

    Jun 5, 2013
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    It is not clear at all what the driver you linked to does. In the list of speicifications, input and output voltages are both listed as 1. This cannot be right. Then later it says the input is 12V AC or DC and output is 600mA 3-12V and output power is 3W. Well, 12V at 600mA is 7.2W, so another contradiction.

    I am going to guess that it takes in 12V and current regulates to 600mA to drive a single 3W LED. If I am correct, you would need to connect all 100 of these in parallel to a 12V supply of unknown amperage since the driver does not give the power requirements.

    Your wiring diagram shows wiring 3 of these in series, that is not likely to work since each would be getting only 4V.

    Bob
     
  13. Remy20122

    Thread Starter New Member

    Oct 30, 2014
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  14. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
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    You could run 3 in series on each cheapo driver with a 12V supply and then do 33 of those series strings in parallel.. But you still need a big (20A) or multiple 12V supplies and break it up into smaller circuits.. and then have fun with that wiring mess :)

    I would still go with 6 strings of 15 LEDs in parallel with a meanwell LPF-40D-54 for each string (6 meanwells). Wire each string one like this on its own meanwell. No junky chinese drivers needed.
    https://reefledlights.com/wp-content/uploads/2012/12/Led-Lights-Chart-12-small.jpg
    The ease of wiring/higher quality/options for dimming are well worth the extra money.

    is this for a reef tank?
     
  15. Remy20122

    Thread Starter New Member

    Oct 30, 2014
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    Ya this is for a custom reef tank; this guy had it built into his house. Its really cool and he says hes putting sharks in there. The final product will be 100 white, 35 red, and 15 blue lights.
    I also purchased these, I believe one is similar to what you suggested.
    http://www.ebay.com/itm/1PC-600MA-3...5V-/371108464499?ssPageName=ADME:L:OU:US:1120

    http://www.ebay.com/itm/7-12x3W-Hig...ew-/231311429808?ssPageName=ADME:L:OU:US:1120

    I am going to try lighting the leds with their own individual drivers though. That ensures that they will all look exactly alike. And I dont mind doing all the wiring. My problem is that I cant figure out how to perfect the circuit.

    you said it might work with a 20A supply; would this power all the lights?

    How can I figure out how to hook these all together and plug it into a wall? Ive studied circuits but ive never created one. Does anyone know a good link they can share?

    I also bought the 2 meanwell drivers to test out (like you suggested). because I do get the feeling that I cant power all these lights from one single wall outlet. the amperage requirements will be too high, right? especially because the 3w led's use 600 mA

    Any thoughts? Comments? thanks everybody
     
  16. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
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    12V @ 20A = 240W
    240W/120V (assuming US voltages) = 2 Amp
    If 240v its only 1 Amp
    So yes its 20A of current flowing on the DC side but only requires 2 Amps from the wall outlet.
     
    Last edited: Nov 11, 2014
  17. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
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    Running them in series will do more to ensure they all look alike and are more consistent vs each having its own source/driver. But you probably won't even notice the difference.
    If you follow what I said above you would also have 6 controllable channels that could be dimmed via a reef controller which I'd suspect a large tank will have. (ps.. I have a saltwater reef too and built all my LED lighting for it and keep up with the trends)

    Wiring is shown above too (just 6 of those circuits).. and you would be building a quality product with ease of maintenance thats dimmable/full control vs cheap drivers that will fail and a spaghetti mess of wiring and no control over the array at all.

    Now.. what color LEDs? (warm white? cool white? neutral whites? k rating?).. 35 red is quite a bit depending on the color temps of the whites..
    Even just 1 red is plenty per 10 LEDs. Adding the new Lime leds really helps improve color rendition. The wrong choice of LEDs and colors can look really drab or the tank looks like a bottle of windex from too much blue or it looks girly pink or purple with too much reds,etc...

    then what are you using for heatsinks and are you using fans for forced cooling?
     
    Last edited: Nov 11, 2014
  18. Remy20122

    Thread Starter New Member

    Oct 30, 2014
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    I am going to try the meanwell product. It has the AC/DC inverter. Will it power the entire string of 15 leds at full power? (thats 3.6v and 600mA each?)

    I also found some great heatsinks and mounting tape that work fantastic:
    http://www.ebay.com/itm/5pcs-20x20x...30-/190709700874?ssPageName=ADME:L:OU:US:1120

    http://www.fasttech.com/product/1350301-20mm-20mm-3m-insulation-thermal-adhesive-tape-20

    I have never used fans for cooling. I attach the lights to the heatsinks with the insulating tape, then attach the heatsinks to some corrugated plastic using double-sided foam tape. The lights dont get too hot.

    i will take your color choices into consideration. will the meanwell power lights of different colors? i heard that the diffrent nanometers(colors) would mess with the string power distribution
     
  19. mcgyvr

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    Oct 15, 2009
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    As long as the sum of the forward voltages is within the DC output rating of the driver it will work fine.. Different colors have different forward voltages. (you originally said 3.4Vf max and the driver I posted will work fine as its output max is 54V and (15 x 3.4 = 51V so you have 3V of headroom)

    generic theoretical example: If I have the following LEDs
    2 x red (max vf=5v)
    4x white (max vf=3v)
    Then 2 x 5v + 4 x 3v = 32V (as long as your driver is rated to more than 32V it will work fine)
    and the current will be the same for each LED..

    I always thermocouple (as close to junction as possible) my LEDs and run them for 2+ hours (it can take that long to reach thermal stability depending on the design.. but its usually after 30-45 minutes though) and log the data.. I never allow junction temps (calculated from thermal resistances and tc attachment point) to go over 65 deg C. And I can get 50K hours easily out of my fixtures.
    One cannot properly judge LED temp by "finger touch" alone.
    While it might "work" fine and not feel "hot" you might not get anywhere close to the rated lifespan of the LEDs.
     
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