View Full Version : Daisy Chain w/ LED's

Chris J
06-15-2008, 12:32 AM
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).

INTEGRA Bespoke Lighting
06-15-2008, 08:13 AM
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.


David Gretzmier
06-15-2008, 04:07 PM
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.

Mike M
06-15-2008, 05:30 PM
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.

Mike M
06-15-2008, 05:37 PM

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.

06-16-2008, 12:32 AM
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.

06-16-2008, 10:33 AM
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.

David Gretzmier
06-16-2008, 06:09 PM
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.

06-16-2008, 06:37 PM
Anti Pierce Point Here!

Mike M
06-16-2008, 06:57 PM
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.

Chris J
06-16-2008, 07:02 PM
Chris, a couple concerns about the photos.


Those are Mike's photos Steve.

sprinkler guy
06-17-2008, 02:03 AM
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.

DG Lights offers a ten year warranty on their new LEDs, and that's the elctronics. It's lifetime on the fixture, which is copper and brass. Also, the LED assembly is replaceable, and the driver can be changed to vary the light output of the LED. Want 3 watts instead of 6? Change the driver. Sherman did this right in front of me; took about 30 seconds. Also, his new LED works between 5 volts and 15. How bad would your daisy chain have to be to acheive this kind of voltage drop/variance from first to last? Like most of you experimenting with LED, I will still continue to design wire runs to handle traditional lighting should the need to change it out come up. I don't know when LED will be the answer for all of our lighting applications, but I could nail most of my situations with what is available right now.

Mike M
06-17-2008, 08:41 AM
If anyone hasn't held a DGLIGHTS fixture in their hands, I highly recommend it. Smart design with the heat sink/cooling fins, and a really beautiful fixture.

I have only been doing this a year, but I just haven't had anyone interested in LED's yet. Seems like design is by far the number one selling issue, and they leave the tech-behind-the-scenes to us. They seem to really care less if it's buried appropriately, let alone solid state vs. halogen, 14 gauge vs. 12, soldered, crimped, nut, hub or t, or hell, they don't even seem to think it's an issue if the whole thing dissolves in a year or lasts a lifetime. They assume we are putting in the goods and it will work. They only judge what they can see: the illumination.

I am sure that down the road, my service and reliability and system longevity will be significant issues for referrals, but even then, I'll bet it's a brief mention and the topic will be the "look."

06-17-2008, 10:45 AM
As we should all know by now, LED lamp life is highly dependent on the temperature management in the LED assembly. If the specified temperature maximum is exceeded even slightly, a dramatic reduction in both lumen level and life occurs. For a good summary, go here: http://www.lumileds.com/technology/lumenmaintenance.cfm.

Checking the DG specs for their two LED MR-16 equivalent spots, one has a maximum temp rated at 124 degrees F; the other at 104 degrees F. These are really low temps; according to Lumileds charts, going 5 degrees past maximum reduces life by about 30%.

Buyer beware!

06-17-2008, 07:25 PM
What exactly are you insinuating Mr. Parrot?

Joey, you've been quick to agree with Mr. Parrot on this thread, what's your position regarding his last post?

06-17-2008, 07:44 PM
Sorry Sherman but I dont see where I have agreed with Steve anywhere on this thread? I have only chimed in regarding pierce points which I strongly believe are a bad choice for connection making.

I do however understand you are reffering to my agreeing with him on the other thread where I presented a test between the Ushio and Kumho LED's next to a 20w BAB. I agreed with Steves mentioning on everyone performing their own field tests and to be on the look out for color/output degrading over time as well as his information regarding LED's being very sensative to heat. Steve tends to be much more articulate in his descriptions in which case I half jokingly replied "yeah, what steve said."

Our tests do show that heat is a huge issue with LED longevity, I dont think anyone disputes that. But I try to be upfront that I am not an authority on LED, I along with most people here and in the industry are learning more and more as time goes on and as more products arrive in the market place.

Now as for your products, I have no opinion on them because I have yet to handle or see them in person. Nor have I seen pictures of them lighting an entire project. I have not spoken directly with anyone who has used them so in turn I have no real field knowledge or information to cause me to generate an opinion either way in reagrds to your products or how they handle the elements over time. what little I have heard through this forum is nothing but good stuff.

Chris J
06-17-2008, 10:09 PM
Yeah, what Joey said.

Eden Lights
06-17-2008, 10:33 PM
Stranded on a Island with LEDS and PARS, I would swim in the warm beautiful waters of MR's.

Mike M
06-17-2008, 11:44 PM


I'm taking Sherman's LED's to the county and asking to illuminate an old school house scene. This could be interesting!

Chris J
06-18-2008, 12:21 AM
Stranded on a Island with LEDS and PARS, I would swim in the warm beautiful waters of MR's.

Ha! Your a poet also! :clapping: :laugh:

06-18-2008, 09:44 AM
"Checking the DG specs for their two LED MR-16 equivalent spots, one has a maximum temp rated at 124 degrees F; the other at 104 degrees F. These are really low temps; according to Lumileds charts, going 5 degrees past maximum reduces life by about 30%."

Joey, based on your temperature testing do you argree with what Steve is saying above?
Does anyone agree?

Sorry Chris, did you ever get an answer to voltage input and voltage drop for your Kichler 15765 LED fixtures?

06-18-2008, 10:50 AM
I would need to get with Rusty (our PE) and see how hot the LED's we have tested got in our brass fixtures and at what hour they failed.

You know more about this than I do so what does it matter if I agree with Steve or not? Why not tell me your views on this and what the temps are in your fixtures... Steve is a knowledgable fellow for sure but something tells me you may know a thing or two more about LED.

Frankly either way I dont really care, if we can get an LED to last 30-50K + hours in landscape and the color is on par with halogen then LED will be well on its way for success and use in the landscape. The problem I have is I still cant get anyone to produce me a photo of a job completely done in LED. And when that photo does get produced I want to see clear proof that it looks as good or better than if that job was done in halogen.

So I guess my beef with LED is LED in general. I am not convinced they last as long as promised, nor am I convinced they are just as good in output and color as halogen lamps are. And I have yet to see proof to make me even come close to feeling otherwise.

06-18-2008, 12:30 PM
It matters what you think because if a manufacturer cannot correctly read the specification then maybe customers are having difficulty as well.

As far as LED color, do you remember Billy's side by side photo of the LED Gemini I made? 1.5W vs 20W. If I remember correctly someone picked the LED as the halogen fixture. Why did you even post photos of the 4200K Ushio LED lamp? Part of using LEDs is knowing how to get what you need.

You can't compare LED MR16's to our fixtures because they're 2 different design approaches. For example the Lamina Sol LED MR16 is not recommended or warranted for enclosed landscape fixtures. The same LED works very well in our fixtures and comes with a warranty.

I have a local 150 fixture project nearing completion, I'll see about having you stop by to see for yourself what our fixtures can do. I was told it's powered using your inground transformers. In the mean time if anyone needs references for real projects let me know.

06-18-2008, 12:55 PM
Operating Temperature: -31F to 124F (-35C to 51C)

Thats your spec.....so to me that reads as operating temperature in your lights....I too would understand that to say anything less or more is not in the optimal operating temperature range which to me would signify that if outside of this range either too cold or too hot there will be the chance of failure.

I understand it this way because of the way the spec is written on the Input Voltage. I see it being 9 to 15 v. To me that means below 9 or over 15 and we are going to have problems.

So with all that beign said I see it that the only way on your lights you are going to get outside of that operating temp range is if you exceed or go below the allowable input voltage range.

So I would have to disagree with the buyer beware statement, but I think what Steve is getting at based upon the Lumileds charts is that if you go beyond the 124F temp you will have problems. Your saying you cant go beyond it because my lights will not allow it as long as you have correct input voltage....correct?

geez I feel like I am in class! LOL

06-18-2008, 01:08 PM
Now in regards to the other stuff.......I showed the Ushio because that was what I had..I also stated they make a warm white in the 3500K range which is much closer in color rendition. My point one was to compare what I had to show differences in color but more imprtantly in output. Both LED's were weak in comparison to the BAB in output. I dont think the photos did a great job in showing that but in person it was very apperant.

I compare MR16's because that is whats available and thats what I have. I dont think it is fair for me nor right of me to display a comparison between my halogen lights and your fixtures (which I dont have) or Kichlers or Vista's. Although i would love to do that I dont want to start a product bashing session.

I just want to see some job photos or look at a job that is done in LED....Until then I am on LED strike.....I want to see a job that looks just as good in LED as it would in Halogen. I dont care if someones wife or a homeowner says it looks great in LED......I want a real lighting designers opinion on how it looks.

Now come over to the factory and bring some lights Sherman!!! From what I see your fixtures are definitly the best looking LED fixtures on the market.

06-18-2008, 02:59 PM
Operating Temperature: -31F to 124F (-35C to 51C)

DG, I apologize. I had a wrong interpretation of your specs. You're right to correct that, but why don't you just come out with a clear explanation to correct my statements instead of needling Joey? Educate us!

06-18-2008, 04:56 PM
Interesting. Your position is no surprise, I remember David Beausoleil's press release from April 2005 cautioning against the premature use of LEDs. To his defense I believe he was refering to the first round of imported MR16 LEDs and had no idea of the other emerging high-brightness technology. Apology accepted.

Joey gets it. The maximum operating temperature applies to the surrounding air temp and conditions for the fixture. It isn't the LED's maximum. The LED has a much higher maximum. The LED inside the Phoenix for example is only operating at 60% of its maximum at 122F, no air-flow.

These aren't new fixtures. They've been tested and in use since 2004.

DG's mission has always been to make a quality LED fixture specifically for landscape lighting. The outdoors is a great place for LED when done properly.

Joey, at almost 100F at your place today don't expect to see me until fall!

Chris J
06-18-2008, 09:28 PM
With all this talk about temperature specs, it has me wondering: If I install the deck lights, which are right out in the open sunlight during the day in the 100 degree FL heat, how hot is that fixture going to be on/in it's surface? I'm having visions of a dog locked in a car on a hot summer day where the temp is significantly higher inside the car.
So, does this mean that the DG or any other manu with specs close to this is not a viable option for us Florida boys? I realize the lights won't be on during the hottest part of the day, but it's still pretty damn hot around sunset.

06-18-2008, 09:51 PM
We have fixtures in Florida all the way down to Key West, Hawaii too.
We test with zero air flow to set maximum temp rating. You should have plenty of air flow on the water. We also design with plenty of safety margin.
When I lived in Florida it seemed like it rained every afternoon in the summer.

Do you have spec for your fixture?

Chris J
06-18-2008, 09:58 PM
No, I don't have the specs. I'll try to retrieve them for critique. Thanks for the reply.

Mike M
06-18-2008, 10:44 PM
Hey Sherman;

Did you get the catalog published yet?

Eden Lights
06-19-2008, 12:21 AM
Leds, Harley Sportster, & MiniVans. I guess I will like these things when I get much older?

06-19-2008, 01:53 AM
Leds, Harley Sportster, & MiniVans. I guess I will like these things when I get much older?

Yes. Yes it does. But not necessarily in that order. :)