My LEDs
FYI: I have been posting updates for those of us who have already read the OP below. For anyone new to the thread, it might be best to skip down below all of these updates, read the body of the post...
Forum Discussion
KendallP wrote:
That's a lot of good theory. And I wouldn't disagree. But do you have test data on the LEDs in question that would support your assertion? After all... you and I have always prefered test data to theory, haven't we. I hope you're not just biased by your experiences with early generation LEDs.
:)bigfootford wrote:KendallP wrote:bigfootford wrote:
Guess someone could load up their batteries and get the battery voltage down into the low 12's then remove the load and see if the cheaper led's dim and brighten...The regulated led's do not change brightness with battery voltage.
Mena has already agreed to do this. Where ya' been??? :)
Repeated pushing will greatly reduce reliability/life expectancy.
That's kind of a bold statement. Are you positive that it will "greatly reduce reliability/life expectancy?" Link, please??? ;)
Glad Menna's going to test. Did not catch that fact.
As for excessive current:
Hundreds of links!
http://www.theledlight.com/technical1.html
LED Technical Specifications and Application Notes
Therefore, a light-emitting diode (LED) is ... is characterized by the degradation of LED ... exceeding the maximum current rating will produce excessive heat within the LED ...
http://leds-led-drivers.com/Engineering-Services/reliability-of-leds.cfm
Current Conditions Of LEDs
Because lattice defects increase with use, the luminous intensity of LEDs gradually declines. The speed of accumulation of lattice defects depends on the magnitude of the forward current.
Jim
Have to depend on the MFG's of the led's to provide their spec's.
Just like Resistor wattage, capacitor voltage tolerances, chip temperature etc. Led breakdown due to running current on the high end of the spec or running them in too warm environment will degrade reliability numbers. No need to test this.
In the testing, that I did with the early super brights I ran them just a little over current spec....The exceeded the temp spec. I ran a few at about 20% over spec. They failed in a couple of days.
Jim
