On November 11, 2009, seven neighbouring locations in the area of Prague-Smichov were converted and the LED Street Lighting Pilot Project started. With the amount of more than 100 replaced lanterns it must have taken some days of preparation. At that time, LEDs were more expensive and less energy efficient than HPS lighting. The goal of the pilot project was to test white light on pedestrians and drivers. Checking the reliability and preserving light parameters of the new lanterns were other reasons. No new poles were installed - it always was an HPS lantern to LED lantern replacement.
Did the LED lanterns last for all those ten years? Three lanterns (out of more than 100) have failed completely and had to be replaced. Maybe ten lanterns have one or more diodes dead, performing mildly worse. Two brands have greened out, giving off light very similar to well used MV/MBFU lamps. The rest looks intact.
The brand installation map below comes from
this article in Czech.
Here's a list of brands with day and night shots showing their condition and night performance after 10 years of use (~44,000 hours in operation).
Click the images for better resolution.
ETNAThe worst score with 2 completely failed lanterns (out of 28 installed). The rest seems to work fine (haven’t checked all of them for failed particular diodes). Not very bright but keeping cool white light colour without greening out.
INDALThree lanterns with some dead diodes, the rest fully lit. Visibly greened out, creating the atmosphere of the park lit by MV lamps with well used MBFU lamps. I like it! The installed amount of lanterns is less than 20.
LGThese are the first lanterns I spotted ten years ago (from a distance) and was really confused (thought they had replaced HPS lanterns with MV or MH ones). They’re still very bright but strongly greened out - making the street look almost like lit by clear MV lanterns. One lantern has failed completely and had to be replaced by a Schréder LED lantern (both of them in the picture for the colour comparison), another one has a pair of diodes dead, the rest is performing fully.
MSCInstalled in two shorter streets both in cool white and warm white version. No failures spotted. They keep the colour without greening out except both ends of the cool white street. Those two lanterns are cool white with a yellowish/greenish tint which could possibly be an experiment with a different kind of phosphor.
PHILIPSThe winner of the competition with no failure among 20 lanterns and no colour shift. On the other hand, these aren’t very bright.
SITECOAlso these don’t show any failures or a colour shift but all of them have the protective plexiglass cracked (click the image to see it better). This hasn’t probably been caused by vandalism but by the weather.
The conclusion?For early LED lanterns from times when LED technology was still young and manufacturing processes not completely established, those a few failures and greening out isn’t so bad for ~44,000 hours of use. How many more years do you think the particular brands will last?
The conclusion of the pilot project might be something like this: Using lanterns from renown makers and not pushing the power too high could make an almost maintenance free installation for more than 10 years with a benefit of energy saving white light.