Solid State-Lighting

[hollarda]

http://www.lrc.rpi.edu/programs/solidState/index.asp

Here is the link above. Does anyone have any thoughts on this technology and do you think that these lights would be able to be powered by transformers?

[sitelights]

At present LEDs are powered by direct current (DC) and thus not readily adapted to conventional outdoor (AC) low voltage systems. A member of lowvolt.org is a manufacturer and distributor of LED outdoor lighting. The URL is on the member's page as Charisma.

Anyone interested in solid state lighting (a.k.a. LED) would profit by a visit to <berkeleypoint.com/applications> where some LED exterior lighting projects are well detailed.

This topic is also addressed in the post "misLED"in the lamps (lightbulbs) & socket forum.

[hollarda]

Reading about Charisma this is their FAQ page. I guess you can use transformers with these lights.

1. Question: How many fixtures can be placed on a transformer?

Answer: Theoretically, the total wattage of all the fixtures should not exceed the total wattage provided by the transformer. With LED bulbs using between 0.9 to 1.5 watts per bulb, we recommend no more than 35 fixtures per 60 watts transformer.

2. Question: How long can I run the main cable from the transformer?

Answer: Even though the kit comes with 100 feet of 16 gauge cable, we have tried 200 feet with 32 fixtures and still see no subjective difference in the light output. This is not possible with a regular incandescent system.

3. Question: How far apart should I place my fixtures along a pathway?

Answer: We recommend every 6 feet. However it is good to experiment to find the proper set up for your home.

4. Question: Can the fixtures and bulbs get wet?

Answer: Yes, they are designed for outdoor use. However avoid total submersion unless it is an underwater light.

5. Question: Can the transformer get wet?

Answer: Yes, it is designed for both outdoor and indoor uses. However, do not lie it flat. It should be vertical and at least 1 foot above the ground.

6. Question: How much light does fixture produce?

Answer: Each fixture produces about the same intensity of a 12-watt bulb. It throws about 2.5 feet to 3.0 feet circle of light when pointed downward.

7. Question: Can I use LED landscaping lights with my existing low voltage system?

Answer: The short answer is yes, but there are a few things to consider:

A. The system must be 12 Volts
B. The existing transformer may not work with LED's (use our transformer)
C. If you use regular incandescent bulbs and LED's on the same line, the voltage drop may be too much and the LED's may not turn on.
D. Your cable may be too large for the connector unless you use wire twisters

[sitelights]

The claim made on the Charisma FAQ page in item: "6. Each fixture produces about the same intensity as a 12-watt bulb." is not correct, nor is it almost correct. The "about" hedges the statement so that their claim is meaningless. What does "about" mean in this context? Is "about" to be taken as a direct equivalency i.e. their 12-watt LED is "about" the same intensity as a 93 SCB incandescent miniature automotive type lamp?

Just as "about" hedges the issue, "intensity" is not defined. My post "misLED" in the lamps forum states "The LEDs were luminous but not illuminating." Their 12-watt LED produced 033 FC which is 1/10th of the output of a 93 lamp. The word "luminous" means "emitting or seeming to emit a steady suffused light..."; "illuminating means "make bright with light: bathe in light". The LEDs I tested had the same output as a small plug-in night light: the kind with the 1" square flat panel emitter.

There has been steady improvement in the performance of LEDs so perhaps my earlier post on this topic is out of date. Statements of equivalency must be viewed with skepticism for now. High output LED arrays are currently being offered in the latest high-end automoblies as headlights; it is only a matter of time until the type catches up with the hype. I put it at five years (2009) until high output LEDs match halogen sources.

[EasyTron]

We have developed a 12v AC LED light strand. They are weatherproof and run off 12v AC low voltage power. When I began installing them in my own landscaping, the neighbors were coming from all over to see them. I was amazed at how many people were wanting them, so made it my mission to perfect them. I'm an Electronics and Technology high school teacher, so this is my passion.

The lights literally make your plants, trees and other landscaping glow from the inside. each strand has a 3-bulb super bright LED cluster. They come in blue, green, white, amber, violet, red and orange/red. Each strand is 10' in length and has a hook wire that allows them to be attached and positioned in any position. The wire used is direct burial wire, and is rigid so you can actually twist it to fit in your plants. You can see the lights at my home in the pics at our website. We sell the strands for $12 each with discounts for quantities. You can call us on our toll free number (888) 621-3317 or our website is: www.easytron.net/led