Complete Noob question about Voltage vs Brightness....

[IPSC_GUY]

Ok here is the question. With a 3W Cree LED drop in that is rated from 3V to 12V, will running the LED at say 9V cause it to be brighter than at say 6V?

IPSC_GUY
SIERRA II ALPHA

 

[Marduke]

Anything above 4v will be the same brightness.

 

[orcinus]

... but may cause tint shifts throughout the voltage range (at least i think).

 

[Steve L]

Ok here is the question. With a 3W Cree LED drop in that is rated from 3V to 12V, will running the LED at say 9V cause it to be brighter than at say 6V?

IPSC_GUY
SIERRA II ALPHA

It depends on the driver that's being used. Generally speaking it will have a sweet spot where it will be most efficient. When the specs say it will operate between 3-12v it just means it will work at those ranges, not necessarily be at it's brightest or most efficient at all voltages through the range. If the driver is only using a buck circuit it will get dimmer below ~4v
EX: 1. Both the Tiablo A9 and Lumapower MRV have wide input ranges of ~2v-8.4v. Both are at there brightest when using two RCR123s but at there most efficient using an 18650.

 

[Gunner12]

The LED is just the LED. If the drop-in only had an LED and the reflector then you have to use a battery source around 3.5-3.7v. Higher and the LED might draw too much current and overheat, lower and the LED might not be bright enough. Because of this the LED is coupled with a driver, in this case a buck driver which lowers the voltage to something the LED accepts for a certain current.

Will running the light at 9v be brighter then 6v, well that depends a lot on the driver used but from what I read about those drop-ins, anything above 5-6v is pretty stable output wise(as in 6v will be similar in output to 9v).

You should get more runtime with 9v but output should be pretty similar.

 

[IPSC_GUY]

THANKS for the education I appreciate it. This is an IR LED by the way so determining if it is any brighter though a NVD is a bit tougher. I plan to get out in a no moon, overcast condition and see if there is any difference.

Again Thanks,

IPSC_GUY
SIERRA II ALPHA

 

[MrGman]

What are you going to use to detect the IR spectrum, you aren't going to "see" the difference with your eyes? A lot of the new digital video cams have an IR mode, your IR flashlight might make a very nice source to run them at night.