LED Project (wiring 3 or 4 LED lights together for underwater project)

Discussion in 'General Electronics Chat' started by discus_harry, Apr 10, 2015.

  1. discus_harry

    Thread Starter New Member

    Apr 10, 2015
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    I appreciate the forum. And further appreciate any advice. My mind feels like mush, after reading too much. I have no knowledge of circuits. Hope I've found some friendly people with a creative side.

    Small project (wanting some underwater lights near my house)

    I want to wire 3 or 4 of the following, together (lets assume 3, for the sake of argument)
    http://www.ebay.com/itm/Outdoor-10W...512?pt=LH_DefaultDomain_0&hash=item3f4a5883b0

    You can easily buy the ac/dc adapter to plug this single light into 110/120.
    It reads: Driver: 10Watt, AC90-264V Output: DC12V

    Works splendid. But, I want more than one light one one plug (or, 30 feet of wire and three of these at the end of it, so I don't have to run 30 feet of wire x3). It will be a fun underwater project near my house. I have a dock at my house and would like to run a few of these around the base, to illuminate it.

    As easy as the following?
    http://www.amazon.com/gp/product/B00FWO24US/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1
    Split the positive LED line and use 3 10watt resistors? Resistors necessary if the power supply pushed 30watts and 3 10w LED Lights are wired to it (parallel, not series)?

    I'm eye-balling a cluster of lights/power supplies I've collected...and fear that my decision to play with electrical tape will result in burned out toys :)


    Again, I appreciate any advice/thoughts
    Direct links to products that could help would be greatly appreciated, given my limited knowledge
     
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  2. #12

    Expert

    Nov 30, 2010
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    Looks to me like a plain old 12 volt light bulb, as far as the wiring goes.
    Everybody else see it that way?

    Just get a 12 volt DC converter and pretend it's a car battery.
    Make sense?

    Wait...it does say it works under water. It receives commands to change color under water. Huh? Never wood have guessed that.

    Yes, the photo shows exactly 2 wires to the LED. How you get color information into it is a mystery to me.
     
    Last edited: Apr 10, 2015
  3. discus_harry

    Thread Starter New Member

    Apr 10, 2015
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    It has a nifty little remote control that will change lights, even allow it to be programmable.
    I suppose I'm most interested in the proper power supply, to light 3, 4, 5, 6, etc of them (so I have one power cord to plug-in for several lights, which is far easier than 7 individual cords)
    I have a 12 volt DC converter that is matched to a single light. The issue is wiring 2 or 3 of them, and which power supply I'd need for that
     
  4. #12

    Expert

    Nov 30, 2010
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    You already figured out that 3 lamps need 30 watts and 4 lamps need 40 watts. Each lamp only has 2 wires, so what to connect them to? The DC converter. All lamps in parallel as far as I can tell, but...
    You might open the box and find out they are using some kind of digital signaling on the DC line to command color changes. That would require a separate cable for each lamp and I can't tell from the advertising.
     
  5. discus_harry

    Thread Starter New Member

    Apr 10, 2015
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    No worry for me to match volts or amps or ohms?
    Thankfully, they only have two wires

    Resistors needed? If i'm parallel wiring the 3, each will divide the 10watts? Or do I need to ensure that with a resistor?
     
  6. #12

    Expert

    Nov 30, 2010
    16,261
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    PLAIN OLD 12 VOLT LIGHT BULBS
    How many resistors do you install in the light sockets of your car?
    Zero.
    How many volts do you supply?
    What the label says. 12 volts DC
    You already said you plugged one into a 12 volt DC adapter with no resistors and it works.
    What's the problem?
    You want to engineer something? If you do, buy some LEDs that aren't already designed, built, enclosed, and labeled, "12 volts". Then we will math up some resistors for you.
     
  7. discus_harry

    Thread Starter New Member

    Apr 10, 2015
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    I'll give 'er a shot. Thank you
     
  8. djsfantasi

    AAC Fanatic!

    Apr 11, 2010
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    The simple answer has been given. Other than matching 12VDC, I do want to reiterate a point that has been implied. The point I'd like to reiterate is, you do have to take total watts into account!
    (# lamps) X 10 Watts/lamp = Total Watts
    Your power supply needs to be rated at greater than the total Watts.
     
  9. discus_harry

    Thread Starter New Member

    Apr 10, 2015
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    But too much power supply and I'd risk burning out the LEDs?
    I couldn't put a 70W power supply on these 3, could I? Or does the power supply regulate in some manner?
     
  10. djsfantasi

    AAC Fanatic!

    Apr 11, 2010
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    Circuits only draw the current they need. The wattage rating on a supply is what it could deliver, not what it does deliver.
     
  11. DickCappels

    Moderator

    Aug 21, 2008
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    Per djsfantasi, there is almost certainly a power supply inside the lamp housing that will regulate the current to the LEDs. Just put 12 volts in and let the internal regulator draw what is needs.

    By the way, since this is going to be used in and around a body of water, please be sure to connect one of the power supply outputs to a good earth connection. I think that if I were doing it, It would insulate well, ground well., and use a ground fault interrupter (GFIC) on the AC input.
     
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