Quote:
Originally Posted by ps2fixer
Light vs watt... I would say below spec driven LEDs would be more efficent.
Latest news I can find about cree (one of the most efficent brands)
CREE |Cree 231 Lumen Per Watt LED Shatters LED Efficacy Records
And a good read about Led efficentcy vs watt usagage etc.
White LED lumen testing
Seems the newer Cree leds should be at or above 100lm\w at say 350ma-400ma draw.
Side note on this, there is a graph in that thread (somewhere around the 9th page) which shows date vs led efficencies with a good up trend for best, and worst being almost flat lined.
I tried to do a quick search on HID LM output vs W usage I found a like on this site! Another great read. All in all, I think correctly designed LED application should be the best bang for power usage and $ with some fab skills.
EcoFit Lighting
Oh and one more thing to remember with "raw" LEDs, you must limit current in some way. Resisters are simple but lowest efficency while a dc to dc constant current driver is probably the best you get (80-90% max). I do not know if HID lights are measured with or with our their power drivers, more research is needed >,<. |
HID's operating principle requires high heat to work so there is no need to limit it. As the HID bulb temp heats up, it's current draw goes down. LED's on the other hand require special attention to thermal management. This is not impossible, but can be very difficult. Methods employed are the use of light tubes or lightpipes to get the light right where you want it while keeping the LED in a location where heat can be effectively removed. Heatpipes can also be used to remove heat from the LED while having it in an area that's not conducive to heat rejection. LEDs are neat in the fact that they can be driven by pulsed supplies at higher average wattage than they were designed for to get lower heat output, and can be driven at frequencies that look constant to the naked eye.
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