I came across this beautiful article in the LED Magazine which speaks volumes about this excellent product depicted in the picture below.
Crossroads LED company supplied 80 units of 70W LED Street Lights 5 years back; with zero failures and zero maintenance! Now that’s some achievement!
The Crossroads project was in the Railyard District, a dining, arts, and entertainment district in Santa Fe, NM where local leaders wanted to conserve energy while maintaining a historic look and feel.
The Prestige Series retrofit kits developed by Crossroads used Bridgelux Vero chip-on-board LEDs, a MeanWell driver, and LEDiL optics paired with each LED.
Santa Fe City engineers tested Crossroads Prestige technology and confirmed that at 30-ft mounting heights it would deliver the desired 2-footcandle (fc) or 21.5 lux average illuminance. Efficacy was verified at over 130 lm/W with a 70W kit replacing 250W high-pressure sodium (HPS) lamps. With roughly a 70% reduction in energy usage the retrofits delivered a glare rating of 2 despite outputting 9100 lm with the drivers set for 70W.
Still, what caught our attention about the project and prompted this story is the demonstrated reliability. And it appears careful thermal design and a multi-stage thermal mitigation scheme are key to the longevity of the Prestige retrofit kits.
Vice president of engineering Buddy Stefanoff said that the thermal design, encompassing conduction and convection, maintains LED die temperature at 57°C whereas the LEDs are rated for a typical die temperature of 105°C. The LEDs are mounted on a thermally-efficient substrate that handles first-stage thermal transfer to an extruded aluminium heat sink that serves as the second stage inside the luminaire assembly. The heat sink assembly is in turn bonded to the metal fixture housing that serves as the third thermal stage and allows dissipation of heat into the air.
Crossroads asserts that its thermal design is more efficient than what is found in most outdoor luminaires and results in significantly lower die temperature.
This project demonstrates that we can make excellent quality LED products and execute such new or retrofit projects successfully. No doubt, care needs to be taken in terms of the Thermal design as the most important factor for longer gestation projects like 5 or 7 years.
If we are in a relatively hostile electrical environment, like in India, we will need to look at the surge and high voltage rating very carefully. Experience shows that for a rating of 230V AC nominal it is desirable to make the product fit to handle 440V AC. In other words, twice the nominal rating is required to make it durable enough to make the product maintenance free and long life.
I am reminded of two examples from my own experience. The first one goes back many decades when CFL had first arrived in India. I was excited to buy 3 units of a leading brand for my house at an exorbitant price of Rupees 700 (around USD 10) each at a time when the price of the prevailing incandescent lamp was Rupees 10. My wife was very much disapproving of the purchase which seemed ridiculous in terms of the price. I tried to convince her of the energy-saving economics. However, the logic of economics quickly broke down within a few months as the CFL lamps started failing at the rate of one piece per month! Obviously, the CFL lamps were imported and marketed in India and were unable to face the onslaught of the hostile off-line conditions in India.
The second example I would like to cite is of a beautiful LED product which was launched very successfully in Europe by a leading brand again. It had a life rating of 25K hours and failed within 25 hours!
So, there is a lot to learn and keep in mind here, from the good Crossroads luminaire, the imported CFL and the imported LED lamp.
But, having said that, we do have a situation where our LED products which are expected to be so good in quality and life land up in the market with another so good performance record and need frequent maintenance and replacements.
Getting the quality and durability and life right for LED products is quite an Art and also a Science.
I, therefore, invite good and bad examples for my collection and research on LED products quality from all friends reading this post.
I also invite readers to contact me by using the link below in case they are concerned with the quality of their products in the market.
My consulting outfit specialises in this area and can help you iron any LED product in production to get it a better response and reputation for itself, You, and your Company!
Best wishes!
Arun Bhatia