Daisy Chain w/ LED's

Discussion in 'Landscape Lighting' started by Chris J, Jun 14, 2008.

  1. Chris J

    Chris J LawnSite Silver Member
    Posts: 2,808

    If I've got this right, I'm going to save some wire here:

    Got a big job to do that involves a 200' dock. I plan on 10 LED luminaries down each side that operate at 1.9w. (20 lights total on two different runs).
    I think I can daisy chain these, and run the entire length on each side with one 12/2 cable on each side. Am I missing something, or will this work? I'm being told that the voltage has to be within 9 to 15 volts (give or take). At this low wattage, I think I can pull this off with no problems but I just want clarification. I'm using the Kichler 15765 luminaries (sconces).
     
  2. INTEGRA Bespoke Lighting

    INTEGRA Bespoke Lighting LawnSite Platinum Member
    Posts: 4,102

    Sounds right to me Chris. Just introduce a bit more voltage tolerance then they claim. I personally would not try to feed 15v to the LEDs, and when you meet the lower voltage limit they will sometimes flicker and sometimes just shut down.

    Simple isnt it?

    Personally, I would tend to spec. the transformer and cable layout as per a traditional LV system so that you don't have any issues if you need to revert back to incandescent fixtures / lamps, but you have little to loose if you are only doing a dock.

    Enjoy.
     
  3. David Gretzmier

    David Gretzmier LawnSite Gold Member
    Posts: 3,645

    according to my charts, at 20 watts per run, It sounds like you'll have only a volt drop or so at 200ft. be sure and use a quality 50 watt trans to allow for a maximum 80% load. heck, splurge and use a 100 watter. I'd like to see pics when you're done.
     
  4. Mike M

    Mike M LawnSite Bronze Member
    from usa
    Posts: 1,941

    Okay, couldn't remember which thread I was in when I mentioned this last night.

    It makes sense here.

    Pics of LED's by DGLIGHTS, 5w at halogen 20 equivalent.
    Cable: 190' 14 gauge between to enhance voltage drop, not enough, so I spliced in a 50 watt PAR36 between the two and aimed it away from the scene.


    Pic #1: 14v tap, 12.8 v on left side, 7.9 on right.
    Pic #2: 15v tap, 13.6 on left, 8.5 right.
    Pic #3: 12v tap, 10.9 left, 6.4 right.

    One Note: I couldn't stand the humidity and had little patience to frig around trying to remember how to lock the shutter/aperture/iso, etc.

    From eyeballing it, I couldn't tell, but the 6.4 did seem a little dim. I was told they blink instead of fade, but have found they begin fading when they are under volted long before they start blinking.

    Color temp looked normal in person, greenish in photo's.

    12vtap.jpg

    14vtap.jpg

    15vtap.jpg
     
  5. Mike M

    Mike M LawnSite Bronze Member
    from usa
    Posts: 1,941

    Chris,

    Another big topic is connections. Curious how you will be doing this.

    I recommend you check out Hadco pierce points. I found some mastic tape at Lowe's which looks like a nice way to cover them for extra protection.

    I would hate to cut-and-nut so many times, dicing up the main run. If I did splice, I would solder, since that's how I do my connections anyways. The Hadco's are made for 12 gauge main runs.

    Also, based on what Steve P. said, we need more technical info on ideal voltage range. 15 v may or may not be too high. I know Kichler has admitted some revised numbers on the range.
     
  6. ChampionLS

    ChampionLS LawnSite Bronze Member
    Posts: 1,066

    We've already done plenty of dock work using tap connectors, but placing them in a carlon junction box with weather tight cord grips. It was a little overkill, but the installation went fast, and there was no cutting of the supply cable.
     
  7. steveparrott

    steveparrott Sponsor
    Posts: 1,173

    Chris, a couple concerns about the photos.

    First, the light dimples along the bottom of the beams looks to be a poor optical design in the LED lens. My LED flashlight has the same beam pattern.

    Second, the fact that there does seem to be differences in brightness among source voltages (assuming that your camera settings were the same for each shot) is a concern. The driver's voltage regulator is not doing a good job providing a consistant forward voltage and current to the LED. LED's are extremely sensitive to forward voltage and current level. If you see brightness changes within the specified range, then you can be sure that the LED is at risk of premature burnout.
     
  8. David Gretzmier

    David Gretzmier LawnSite Gold Member
    Posts: 3,645

    nice photo's. all the lights look the same to me, but perhaps my eyes are not what they used to be.

    Pierce points? PLEASE . I have yet to find any that did not compromise the wire. the entire pierce assembly and each end of the leads/supply wires would need to be sealed in an epoxy chamber to be waterproof for buried or free air applications.

    I did a repair on a system that was at least 20 years old the other day. nasty old glavanized junction box had rusted out in the ground, and the gaskets had failed. poured rusty water out of the box and found old school wirenuts. the electrician that installed this filled the nuts with what looked like axle grease, it was jet black. cutting into the 8 guage wire, the wire was absolutely clean copper. Thank you electrician for seeing the need.

    It takes me about 2 minutes to cut, strip 4 12 guage wires and the two leads from the fixture, and wire nut the assembly with waterproof wire nuts.

    In this dock application, If you can't hide the connectors, then I'd look at the ace's, but timewaide your closer to 5 minutes per fixture to heatshrink the tubing.
     
  9. JoeyD

    JoeyD LawnSite Silver Member
    Posts: 2,933

  10. Mike M

    Mike M LawnSite Bronze Member
    from usa
    Posts: 1,941

    Dave, my eyes are not the best these days, but I really couldn't see a difference across the voltage range.

    Amazing that I had 190 feet of #14 cable between the fixtures with a 50 watt PAR in the middle, too.

    Longevity is an issue. If the LED fails, you have to replace the whole thing. Kichler is offering 5 years on the aluminum. Not sure of the brass.

    I like the idea of the ace instead of cut-n-nut. Nice inline splice. With smaller wire, why not just use those crimp type heat shrinks? Talk about a fast install.
     

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