Sakugenken
Newly Enlightened
It seems like most of the new traffic lights here are LED. Is that also happening in the States?
LED Trafic Lights
- Thread starter Sakugenken
- Start date
NewBie
*Retired*
Yes, the same thing is happening in many areas of the States.
Unfortunately, alot of cities went with the bottom dollar bids from folks using LEDs from HK and similar areas, and that or other parts of designs fail very early, in some cases resulting in an average lifetime of six months to failure.
Unfortunately, alot of cities went with the bottom dollar bids from folks using LEDs from HK and similar areas, and that or other parts of designs fail very early, in some cases resulting in an average lifetime of six months to failure.
Sigman
* The Arctic Moderator *
Railroads converting as well...
[ QUOTE ]
NewBie said:
Unfortunately, alot of cities went with the bottom dollar bids from folks using LEDs from HK and similar areas, and that or other parts of designs fail very early, in some cases resulting in an average lifetime of six months to failure.
[/ QUOTE ]
I'd say the problem stems more from the circuit driving the LEDs than from the LEDs themselves. I've been using those "cheap" HK LEDs you speak of and I'm quite satisfied as to their brightness and quality. The only thing cheap about them is the price, which is good because at $1.50 each or more Nichias are quite frankly a ripoff. The key with LEDs (or any electronics) is to have adequate surge and spike protection. Sadly, many of the current LED traffic light designs were made by people used to working with incandescents. As a result, they're lacking in the protection department. Also, a simple resistored setup is not the way to go. You need at least filtering and current limiting.
NewBie said:
Unfortunately, alot of cities went with the bottom dollar bids from folks using LEDs from HK and similar areas, and that or other parts of designs fail very early, in some cases resulting in an average lifetime of six months to failure.
[/ QUOTE ]
I'd say the problem stems more from the circuit driving the LEDs than from the LEDs themselves. I've been using those "cheap" HK LEDs you speak of and I'm quite satisfied as to their brightness and quality. The only thing cheap about them is the price, which is good because at $1.50 each or more Nichias are quite frankly a ripoff. The key with LEDs (or any electronics) is to have adequate surge and spike protection. Sadly, many of the current LED traffic light designs were made by people used to working with incandescents. As a result, they're lacking in the protection department. Also, a simple resistored setup is not the way to go. You need at least filtering and current limiting.
They have been putting them in here... and most people cannot tell the difference in the incans and LED traffic lights. The major advantage over incans is replacement cost, I would guess it costs more for someone to replace the incans every once in awhile than to put in an LED version once and hopefullly only replace it once in 5-10 years or so.
greg_in_canada
Flashlight Enthusiast
[ QUOTE ]
jtr1962 said:
I'd say the problem stems more from the circuit driving the LEDs than from the LEDs themselves. I've been using those "cheap" HK LEDs you speak of and I'm quite satisfied as to their brightness and quality. The only thing cheap about them is the price, which is good because at $1.50 each or more Nichias are quite frankly a ripoff. The key with LEDs (or any electronics) is to have adequate surge and spike protection. Sadly, many of the current LED traffic light designs were made by people used to working with incandescents. As a result, they're lacking in the protection department. Also, a simple resistored setup is not the way to go. You need at least filtering and current limiting.
[/ QUOTE ]
There may also have been not enough testing done for
thermal cycling (causing solder joint failures) and
vibration (notice the road vibrating when a heavy truck
goes past).
Greg
jtr1962 said:
I'd say the problem stems more from the circuit driving the LEDs than from the LEDs themselves. I've been using those "cheap" HK LEDs you speak of and I'm quite satisfied as to their brightness and quality. The only thing cheap about them is the price, which is good because at $1.50 each or more Nichias are quite frankly a ripoff. The key with LEDs (or any electronics) is to have adequate surge and spike protection. Sadly, many of the current LED traffic light designs were made by people used to working with incandescents. As a result, they're lacking in the protection department. Also, a simple resistored setup is not the way to go. You need at least filtering and current limiting.
[/ QUOTE ]
There may also have been not enough testing done for
thermal cycling (causing solder joint failures) and
vibration (notice the road vibrating when a heavy truck
goes past).
Greg
greenLED
Flashaholic
We got'em here too (only green, though), and we've started to notice some LED burned (in rows??). Actually, a couple of lights have been changed back to incan.
greenLED
Flashaholic
Yup, there were 4 or 5 LEDs in a row, smack down the center of the light. I have no clue how these are wired and why a row would burn out.
Once again as was said; probably the circuitry. In Times Sq. also, all those new full color signs; after a few months, you see lines out, lines that don't go out, or stay one color; and the same with whole square panels, and even some individual ones scatered around.
The traffic lights here, however; you rarely ever see any out. I saw a line out in the reds when they were fist installed; but not since. Sometimes you do see one aspect flickering dimly when it should be off. Also, here in NY, they have skipped the yellow. From what I hear, the city didn;t like the amber, and since that color is on the least, itdidn't make sense to change them.
The traffic lights here, however; you rarely ever see any out. I saw a line out in the reds when they were fist installed; but not since. Sometimes you do see one aspect flickering dimly when it should be off. Also, here in NY, they have skipped the yellow. From what I hear, the city didn;t like the amber, and since that color is on the least, itdidn't make sense to change them.
ReynolS
Newly Enlightened
They are all over the place here in the Phoenix Arizona area!
bobisculous
Flashlight Enthusiast
Yea, we have about 2 intersections in my area of Houston(northeast)... They suck! Houston didnt spend any money on em therefore they are crap and are going out. They flicker in rows. I know that its Houstons fault(for not spending money on them) and not weather or anything cause right outside of Harris county and into Montgomery county(right where I live), they have some and they have worked great...Montgomery county knows how to time a light as well and waste less gas.
Cameron
Cameron
Ratso
Enlightened
One thing I like about LED lights is that they are not washed out by the sun as easily. LED's seem to be more visible than incandescants.
Leeoniya
Enlightened
we have quite a quite a few as well. most semi trucks are going that route too...as every other kind of indicator should. leds are definitely brither, prtoabably cause each one is focused, but the whole point is for them to be that way since they need to be, in essance, directional. thats why there were those new lights for a while that you couldnt tell wtf color was on from the side, polarized or something. it was always strange to me that only the greens were initially converted, rather than all of them. i would think it would be easier to not go cross-system as far as circuitry goes to have both incan and leds in the same stoplight. and yes, the current limiting is critical as well as spike protection, it doesnt cost much to place several TVS chips and capacitors into a circuit that is mass produced, much cheaper than recalling every one that blows out. and as far as brightness, again, i can tell and LED light around here from an incan one from probably a mile away, but definitely at least half a mile. and if you stare into one as you're passing it, or standing at a red, it does hurt the eyes. : )
Leon.
Leon.
MikeLip
Flashlight Enthusiast
Our small town has replaced all the traffic light lamps with LED arrays. So far so good. I haven't noticed any of them out. They're easier to see than the old incandescents, too.
NewBie
*Retired*
[ QUOTE ]
jtr1962 said:
[ QUOTE ]
NewBie said:
Unfortunately, alot of cities went with the bottom dollar bids from folks using LEDs from HK and similar areas, and that or other parts of designs fail very early, in some cases resulting in an average lifetime of six months to failure.
[/ QUOTE ]
I'd say the problem stems more from the circuit driving the LEDs than from the LEDs themselves. I've been using those "cheap" HK LEDs you speak of and I'm quite satisfied as to their brightness and quality. The only thing cheap about them is the price, which is good because at $1.50 each or more Nichias are quite frankly a ripoff. The key with LEDs (or any electronics) is to have adequate surge and spike protection. Sadly, many of the current LED traffic light designs were made by people used to working with incandescents. As a result, they're lacking in the protection department. Also, a simple resistored setup is not the way to go. You need at least filtering and current limiting.
[/ QUOTE ]
Actually, the Nichias get cheaper in volume, at 0.43 ea for whites, and cheaper in other colors. Though if I was doing colors, I'd highly consider Toyoda-Gosei.
Also jtr1962, are your HK LEDs exposed directly to the weather...?
BTW, someone is using some sort of different setup on some around here, my wife pointed out single LED failures to me one day, and we have seen green traffic lights with up to five random dead LEDs. Either they are individually driven, shorting out individually, or there is a bypass diode that turns on when the LED is out...
jtr1962 said:
[ QUOTE ]
NewBie said:
Unfortunately, alot of cities went with the bottom dollar bids from folks using LEDs from HK and similar areas, and that or other parts of designs fail very early, in some cases resulting in an average lifetime of six months to failure.
[/ QUOTE ]
I'd say the problem stems more from the circuit driving the LEDs than from the LEDs themselves. I've been using those "cheap" HK LEDs you speak of and I'm quite satisfied as to their brightness and quality. The only thing cheap about them is the price, which is good because at $1.50 each or more Nichias are quite frankly a ripoff. The key with LEDs (or any electronics) is to have adequate surge and spike protection. Sadly, many of the current LED traffic light designs were made by people used to working with incandescents. As a result, they're lacking in the protection department. Also, a simple resistored setup is not the way to go. You need at least filtering and current limiting.
[/ QUOTE ]
Actually, the Nichias get cheaper in volume, at 0.43 ea for whites, and cheaper in other colors. Though if I was doing colors, I'd highly consider Toyoda-Gosei.
Also jtr1962, are your HK LEDs exposed directly to the weather...?
BTW, someone is using some sort of different setup on some around here, my wife pointed out single LED failures to me one day, and we have seen green traffic lights with up to five random dead LEDs. Either they are individually driven, shorting out individually, or there is a bypass diode that turns on when the LED is out...
