what is the point of overdriving?!?!?

[skillet]

If a lux V is rated at 750mA for max ouput.. what is the point to drive it with 1000mA?? Is it really brighter like overdriving an incan bulb?... Seem like you shorten the life to no beneficial end......

Skillet here... /ubbthreads/images/graemlins/confused.gif

 

[jtr1962]

It depends on the characteristics of what you're overdriving and of course whether or not the greatly shortened lifetime is detrimental to your application. No point at all to overdriving the Luxeon V due to to the lifetime issues and also you don't get that much extra light going from 750 mA to 1000 mA. Mildly overdriving the Luxeon III to maybe 1.2A or 1.3A may make sense if it's on a really good heat sink. The Luxeon (i.e. 1 watt) is the most overdriveable of all as far as getting additional light output. Lamina Ceramics LED arrays seem extremely overdriveable provided you use very good heat sinking (i.e. the same type you would use for a Peltier cooler of the same size).

 

[idleprocess]

Overdriving LEDs makes them brighter - usually at the expense of efficincy, almost always at the expense of life.

You can drive a Lux III at 1.3A if your heatsinking solution is good enough, but most report that the only difference between 1A and 1.3A is that the emitter generates a great deal more heat. A light meter can tell the difference, but your eyes will have difficulty seeing it.

Lamina arrays are overdrivable - they're specified in such away that you need only keep the die junction temperature at a given level. The amount of heatsinking required to drive them substantially past their nominal ratings is ridiculous - hundreds of times the mass and volume of the array. Active cooling to reduce the heatsink surface area would require a substantial fraction of the power going to the array.