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I dont understand the wattage of these IR leds. Please help !

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spec:
(update #1  2019_01_21)

Hi AlcidePiR2

Don't try to rationalize specifications for any commercial component/equipment or you will go insane in the brain, just get to the important characteristics. With IR LEDs, they are:
* input electrical power
* IR output power
* IR frequency
* beam pattern
* life

Zero999:

--- Quote from: spec on January 21, 2019, 11:29:17 am ---Don't try to rationalize specifications for any commercial component/equipment or you will go insane in the brain, just get to the important characteristics. With LEDS they are:
* input power
* lumens
* colour (temperature)
* beam angle
* life
--- End quote ---
The second two: lumens and colour temperature are only relevant to visible LEDs. The LED linked to above is infrared so will have a very low output in lumens: near zero.

The colour temperature is only relevant to white LEDs. Colour LEDs are normally specified as the dominant wavelength for monochromatic devices and chromacity coordinates.

Radiant power output, over the desired bandwidth is what's important for IR LEDs and is also used for LEDs at the far ends of the visible spectrum, which are typically used for other applications than direct illumination.

Refer to the papers linked below for more information.
http://depts.washington.edu/mictech/optics/me557/Radiometry.pdf
https://www.thorlabs.de/catalogPages/506.pdf

spec:

--- Quote from: Zero999 on January 21, 2019, 11:42:58 am ---
--- Quote from: spec on January 21, 2019, 11:29:17 am ---Don't try to rationalize specifications for any commercial component/equipment or you will go insane in the brain, just get to the important characteristics. With LEDS they are:
* input power
* lumens
* colour (temperature)
* beam angle
* life
--- End quote ---
The second two: lumens and colour temperature are only relevant to visible LEDs. The LED linked to above is infrared so will have a very low output in lumens: near zero.

The colour temperature is only relevant to white LEDs. Colour LEDs are normally specified as the dominant wavelength for monochromatic devices and chromacity coordinates.

Radiant power output, over the desired bandwidth is what's important for IR LEDs and is also used for LEDs at the far ends of the visible spectrum, which are typically used for other applications than direct illumination.

Refer to the papers linked below for more information.
http://depts.washington.edu/mictech/optics/me557/Radiometry.pdf
https://www.thorlabs.de/catalogPages/506.pdf

--- End quote ---
You beat me to it. I was thinking about visible LEDs. Above post amended.
All the same, the general message about not trying to rationalize specifications and focusing on the core parameters is the important point.

Zero999:
Whoops, I forgot to say that chomacity coordinates are used for LEDs with a non-spectral colour, such as pink, purple, pale green etc. which are made use a deep blue/violet/UV LED and a phosphor coating. Anyway, that's off-topic, as this thread is about an infrared, not a visible LED.

AlcidePiR2:
Obviously,  the main  parameter  here is the  forward current.
westfy was right, 20W  is  probably the denomination of the equivalent  white  led.

In this case https://www.aliexpress.com/store/product/Chanzon-LED-Bulb-1W-3W-5W-10W-20W-30W-50W-100W-High-Power-Epistar-Chips-COB/1913069_32811656870.html?spm=a2g1y.12024536.productList_699027.pic_0

The forward voltage is 30-34V  and thus 600mA  corresponds to roughly 20W.

The equivalent IR leds have a forward voltage of about the half at 12-14V.  So the power at 600 mA is 10W, but the seller still name it 20W, as it is the same package.
This is certainly not the usual convention.

What is  funny is the discussion I had with them asking advice for the led driver :  They recommend a 10W led driver !
see the attached  account of our discussion.

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