Wattage question, am i driving this fully?

KelDG

Newly Enlightened
Joined
Feb 8, 2015
Messages
40
Hi, I have a small project going that needs a 10w IR led.

Now I have it and also have a constant current / voltage board that I can tweak.

The led says it needs 5-6V and 850-1000mA. So I set my board to 5.5v and 850mA. Now it seems to light up fine, I need to wait for tonight to get my IR camera on it. But what I don't understand is where is 10W coming from. P=I*U says the max possible for this LED is 1A*6V=6W. Please tell me I am being a bit thick here and am missing something fundamental.

The only thing I can think of is that the LED looks like a 3x3 grid, so there are 3 in series in 3 chains, that would give around 9V to drive it and total 10W ish when driven at max. But I don't want to pump that through it and blow it up as the data sheet does say 5-6 V.

Any ideas guys? Thanks in advance.

Kel
 

ssanasisredna

Enlightened
Joined
Oct 19, 2016
Messages
457
Hi, I have a small project going that needs a 10w IR led.

Now I have it and also have a constant current / voltage board that I can tweak.

The led says it needs 5-6V and 850-1000mA. So I set my board to 5.5v and 850mA. Now it seems to light up fine, I need to wait for tonight to get my IR camera on it. But what I don't understand is where is 10W coming from. P=I*U says the max possible for this LED is 1A*6V=6W. Please tell me I am being a bit thick here and am missing something fundamental.

The only thing I can think of is that the LED looks like a 3x3 grid, so there are 3 in series in 3 chains, that would give around 9V to drive it and total 10W ish when driven at max. But I don't want to pump that through it and blow it up as the data sheet does say 5-6 V.

Any ideas guys? Thanks in advance.

Kel

IR LEDs are closer to 2V, not 3V. Do you have a proper data sheet for the LED? Can you give us a link to it? It's probably just false EBAY\ALIEXPRESS\ETC. advertising.
 

KelDG

Newly Enlightened
Joined
Feb 8, 2015
Messages
40
IR LEDs are closer to 2V, not 3V. Do you have a proper data sheet for the LED? Can you give us a link to it? It's probably just false EBAY\ALIEXPRESS\ETC. advertising.

Ah cracking, 2v per LED makes sense with there being 3 in series / 3 parallel chains, 5 - 6 volts makes sense. Yeah no proper Data sheet, just the Aliexpress info, no product markings to find one either. I'm not really bothered about it not being true 10W as long as I am driving it properly.

I hooked up another while I was also measuring and upping the current, and I think my power supply driving it is struggling as when I get above 800mA at 6V I start getting a voltage drop, so probably why I am not seeing an increase in intensity, will know tonight if it is any good as ill crack out something a little bit more suitable for the job.

Thanks for the info mate.
 
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