Street Lights for my driveway

[EddieWalker]

I'm working on fencing the rest of my driveway and need to build three more streetlights. I've done four already, but that was years ago. I have all the metal to make them all match, but the High Pressure Sodium 150 watt lights that I bought at Home Depot don't seem to exist anymore. There are some flimsy aluminum looking ones that I'm not comfortable with out there, and then there is what' available online.

While looking, I'm also seeing LED Lights that are claiming to be a lot more energy efficient with the same amount of light. The reviews seem to disagree with the amount of light being even close, and some of them complain about how poorly built the lights are.

What brands are the good ones and what should I look for if I change to LED?

Thank you,
Eddie

 

[EarPlug]

Here is an article about the National Corvette Museum switching to LED 403 Forbidden

 

[CobyRupert]

Bulbs/lamps are usually rated in Lumens, a measurement of the total light eliminated by the bulb.

The lamp's reflectors/refractors then direct (focus, reflect, etc..) that quantity of light over a large or small area. The value of light at a particular spot/surface (angle and distance) from the fixture is measured in "lumens/square meter" = 1 "Lux", or in standard units by "footcandles". ( 1 footcandle =10.764 lumens/sq. meter (Lux)= the light emitted from a candle at a distance of 1 foot.)

So... if you want to compare bulb types, compare lumens. [But note, different type lamps have a different "color" (measured in degrees Kalvin) . Note how at night (high pressure) sodium lights (2000 degK) make everything look yellow. "Warm" incandescent bulbs (2800 degK) make everthing look red/orange, "cooler" bulbs like metal halide (5000deg K) and LED's make everthing look "harsh" white or blue. However coatings can be added to lamps to "cool" them. ]

A 150W high pressure sodium lamp might have 16000 lumens (initially at the start of its life), have a 24,000 hour lifespan, 2100 deg K, and consume 160 Watts.



Next you need to compare the fixture's distribution pattern for that lamp. There's all sorts of distribution patterns and they very widely, with multiple distribution options offered even within the same make/model. (measured in footcandles at a certain distance from fixture, when fixture is mounted at a certain height. A photometric plot/graph showing footcandle lighting "contours" of an area is more useful than just raw numbers ) Basically the fixture spreads that bulb's lumens wide and thin, or focused and narrow and bright, etc..

Fixtures with "Roadway" lighting distributions (Types R2, R3, R4) tend to not throw light forward, like say a spotlight, but have a wide side spread, with type R4 being the widest.

This company represent dozens of product lines: Brands

LED's last a long time and operate cheap, but may cost more up front. Will they last forever is a good question because on some you can't change out the LED bulbs, you have to scrap the whole unit or a large portion of the guts.

Lighting is a funny thing, yes there are the raw analytical numbers that can be engineered, but that goes out the window as the human factor (perception) comes into play. (i.e. the style of the fixture, the "color", etc..) Example of "perspective": (This is counter-intuitive): Security lighting: When you make an area more brighter, you make the unlit and shadow areas more "darker" and easier to hid in. Uniformity (distribution) becomes more important than quantity.

 

[davrow]

Lighting is a funny thing...as the human factor (perception) comes into play.

At my work they recently swapped out all the sodium lights in the parking lot with LEDs.

I like it much better, I think I can see better, especially color rendition.

My boss says it is a lot darker out there, that the LEDs don't put out as much light as the sodiums did.

Perception indeed.

 

[CobyRupert]

At my work they recently swapped out all the sodium lights in the parking lot with LEDs.

I like it much better, I think I can see better, especially color rendition.

My boss says it is a lot darker out there, that the LEDs don't put out as much light as the sodiums did.

Perception indeed.

It can even get more complicated than that. As I understand it, the human eye receptors are made up of rods and cones. One type receptor is good for low light level vision but not so good at color recognition, one good for peripheral vision, other for direct, one good for seeing blues ("cool" lamps), one good for seeing red ("warm" lamps). So, depending on what you were born with, you will see (perceive) things differently.
So it's not really apples to apples (despite what I said before) if 2 lamps both put out 10,000 lumens, but if one is "warm" light, the other is "cool" light, because your eyes' will use the different cones or rods receptors to absorb the different light, what you see (sensitivity, color, peripheral vision) will be totally different.

Sorry if I hijacked this thread.

 

[Coyote machine]

If I were you I'd try a couple of different LED lamps and see what works for you- what you like as far as emitted light. LED lighting seems to be the way things are going these days. HPS was the lighting of choice a number of years ago. In the end budget and what looks good are what dictate what you use.

 

[dragoneggs]

I think LEDs are pretty much a no brainer. I can't personally vouch for them in a 'street light' application but I use them in my outdoor motion sensitive security lights, indoor dimmable lighting, and in reef aquarium lighting! It is amazing the 'amount' of light per watt that you get out of LEDs. Typically the light is very 'white' so if you are looking for warm lighting, that is a challenge. Another very important factor is the reflector design. Now whenever I am looking at new lighting, I look hard to use LED for their longevity and efficiency.

 

[EddieWalker]

I'm a big fan of LED lights and how much they have improved recently. From what I'm reading, they are just not ready to compete with High Pressure Sodium lights for the amount of light you get for the same amount of electricity used or how long they last. At this time, the technology seems to be to stick with the High Pressure Sodium Lights and when they need to be replaced, look at it again to see if LED or something else has come along that is better.

Thank you,
Eddie

 

[HEC]

Paul Short has a video on led light installation on you tube that might give you some info . .

 

[CobyRupert]

Personally, I like and specify metal halide lamps over high pressure sodium. The coloring is much better (IMO)(i.e. whiter) than the yellow sodium. They're as efficient (lumens per watt) as sodium and their lifespan is comparable.