Gambino High Performance LED Landscape Lighting Modules (pt.1)

04 Jul Gambino High Performance LED Landscape Lighting Modules (pt.1)

By Mike Gambino 

This is Part 1 of a two part article on what sets our landscape lighting systems and specifically our LED light sources apart from the rest.

Most current Gambino landscape lighting fixtures use an LED (Light Emitting Diode) light source module specifically engineered to work in our fixtures which are installed in gardens and exposed to all sorts of environmental extremes.

An LED is a semiconductor chip that converts electrical energy directly into light. An LED is classified as a solid-state light source because it has no gas or liquid components, as do other light sources. The LED’s in Gambino landscape lighting fixtures consists of an emitter chip mounted on a solid base also known as a heatsink. the chip is attached to electrical leads that conduct power to it, and is covered with a clear polymer (optic)  that is shaped to focus or disperse the LED’s light in the desired manner.

LED’s generally emit light within a narrow spectral band. In order to produce white light, which consists of nearly the entire visible spectrum combined, we use LEDs that emit near-ultraviolet blue light that strikes an upper layer of phosphors. These phosphors absorb the blue light and re-emit white light. We find our customers love the warm white color (3000 Kelvin temperature) of the halogen light sources we used in years past because they most accurately reproduce or render the true color of the subject itself so our LED’s are tuned to perform similar to this familiar light source.

LED’s  possess tremendous advantages over incandescent lamps. First, LED’s are estimated to last 50,000 thousand  hours versus 5,000 hours for high-output incandescent halogen lamps. Second, because LED’s are very robust in construction, and have no delicate parts such as glass bulbs, reflectors or filaments, they are extremely resistant to vibration and shock, making them well suited for the garden environment.

Third, warm white-light LED’s produce virtually no invisible infrared radiation, as opposed to incandescent lamps, which emit over 85% of their output as infrared, and therefore LED’s are much more efficient in producing light than incandescent lamps — an important factor low voltage landscape lighting fixtures.

Most LED’s emit illumination from a flat surface, necessitating complex reflectors and lenses to produce desirable beam characteristics. Because LED’s are susceptible to potential damage from overheating, they have certain thermal design requirements that dictate the maximum output possible from a given LED, and affect the overall configuration of the specific fixture. LED’s are difficult to manufacture without some variance in lumen output and color. For this reason, they are tested and sorted by the manufacturer into different bins according to output and color. The manufacturer for Gambino LED modules minimizes such product variability by purchasing LEDs only from the highest-quality bins.

Gambino landscape lighting LED modules contain a durable, sealed electronic power regulator or driver  that supervises the operation of the LED. This circuitry assesses power output, monitors system performance, and controls power supplied to the LED. Power regulation or constant power provides a more consistent light output for the usable life of the LED.

Body Materials — Anodized Aluminum LED modules

Although we would never use or recommend the use of aluminum materials exposed in the garden, when installed inside of our weather tight brass and copper Gambino lighting fixtures they perform quite well. Our LED modules are aluminum-body constructed  and machined from a high-strength aerospace aluminum alloy, making them extremely resistant to damage from impact, crushing, or bending, and allowing them to be made as small and light as possible without sacrificing strength.

The aluminum-body is further protected by a finish called anodizing. The anodizing process uses electricity and a chemical bath to grow a layer of aluminum oxide on an aluminum surface. Aluminum oxide is the second-hardest substance known to man, exceeded only by diamonds, and certain anodized finishes can be made extremely durable, such as the Mil-A-8625 Type III Class 2 military specification finish that Gambino uses.

Light Output — Lumens vs. Candlepower

Some manufacturers dramatize the performance of LED’s by measuring output in candlepower units. This measurement can be misleading because it is usually taken by focusing the beam into a narrow cone and taking the measurement in this bright spot, without respect to the overall beam configuration.

Imagine a flashlight whose beam produces an extremely bright spot six inches in diameter when shone against a wall fifteen feet away, but which produces almost zero illumination elsewhere on the wall. A candlepower measurement taken in that bright spot may be quite high, but the flashlight’s beam would be useless for most purposes.

Now imagine taking the total amount of light in that bright central spot and spreading it out evenly into a broad cone. The beam is now in a much more useful configuration, but if you measured candlepower at the same place on the wall where the bright spot was previously you’d get a much lower figure, and the beam as a whole might appear too dim for your needs.

This is why the best starting point for comparing the performance of illumination tools is the lumen, which measures total light output. This puts the illumination tools you’re comparing on a level playing field; you know how much total light you’re getting from each one. After that, the primary performance concerns are (1) beam configuration, meaning the shape of the fixture’s emitted cone of light and how the available light is distributed within that cone; and (2) efficiency, meaning how much energy is required to produce the lumens emitted in that cone of light.

A technical note: although candlepower and lumens measure different things, there is a relationship between them. A light source with an intensity of one candlepower (or candela in modern terminology) that is emitting equally in all directions (that is, in a spherical shape) generates about one lumen per steradian. A steradian is a solid conical shape that can be envisioned as a circular cored-out section of a sphere, wide on the surface of the sphere and narrowing to a point at the center. Since there are about 12.5 steradians in a sphere (4π to be exact), that means our one-candela light source is producing a total of about 12.5 lumens of light.

integrating sphere photometers to measure the total lumen output of our illumination tools.

Check back next friday to read the conclusion of this 2 part article on our High Performance LED’s

This landscape lighting blog is published by Mike Gambino of Gambino landscape lighting inc. all rights reserved. Mike is a professional landscape lighting system designer/ builder and has been designing, installing and maintaining landscape lighting systems for more than 20 years. Mike resides in the Los Angeles area with his wife and 2 sons. To visit his website go to www.gambinolighting.com . To inquire about hiring Mike please click here .

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