#31: Re: LED Numberplate Bulbs Author: Ali_H, Location: Chichester, SussexPosted: Fri Nov 04, 2011 2:27 pm ----
mtempsch wrote:
Debz wrote:
ive got the LED number plate bulbs, how long do they last roughly as they would always blow in my last car and only last a few months
LED's ran within their 'normal' parameters typically last 50-100.000 hours - i.e. would likely outlive the car.
But I'd believe most of the cheap stuff is likely to run them harder (higher current through them which gives more light but shortens life).
Another problem is that (white) LED's operate at ~~3-3,6V depending on exact design, and the car supplies anywhere from about 11-14,5V. If you run a single LED off the cars supply, the difference in voltage must be handled somehow... Simplest and cheapest is a series resistor that at the approximate wanted current through the LED drops the difference between supply voltage and LED operating voltage across itself. Since the supply voltage is not fixed this is pretty much a 'get it close enough' thing anyway...
Also, in a small package like a wedge bulb, the resistor can't be big, and for the possible size, the heat generated in the resistor (function of voltage across it times current through it) becomes pretty significant and might cause the resistor to burn out or solder joints to fail long before the actual LED element fails.
Flamin hell mate, this is Info not Wikipedia
#32: Re: LED Numberplate Bulbs Author: copey, Location: rochdalePosted: Fri Nov 04, 2011 2:35 pm ----
Ali_H wrote:
mtempsch wrote:
Debz wrote:
ive got the LED number plate bulbs, how long do they last roughly as they would always blow in my last car and only last a few months
LED's ran within their 'normal' parameters typically last 50-100.000 hours - i.e. would likely outlive the car.
But I'd believe most of the cheap stuff is likely to run them harder (higher current through them which gives more light but shortens life).
Another problem is that (white) LED's operate at ~~3-3,6V depending on exact design, and the car supplies anywhere from about 11-14,5V. If you run a single LED off the cars supply, the difference in voltage must be handled somehow... Simplest and cheapest is a series resistor that at the approximate wanted current through the LED drops the difference between supply voltage and LED operating voltage across itself. Since the supply voltage is not fixed this is pretty much a 'get it close enough' thing anyway...
Also, in a small package like a wedge bulb, the resistor can't be big, and for the possible size, the heat generated in the resistor (function of voltage across it times current through it) becomes pretty significant and might cause the resistor to burn out or solder joints to fail long before the actual LED element fails.
Flamin hell mate, this is Info not Wikipedia
well if the information is true, it certainly aint wikipedia
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