Lighting 3W power LED

[dziubym]

I am quite a beginner.
I am building a project in which I want to light up the 3W Power LEDs I bought online.
I tried it with 9v power supply and a step down buck converter going back to 5v throough 330Ohm resistor.
The light is not very bright. I would like to know what is the most optimal way to power LED to get the brightest light but not to fry it. How do I calculate. Do I need a resistor.
The LED I have is
https://pl.aliexpress.com/item/5PCS...594.html?spm=a2g0s.9042311.0.0.35895c0fRZ4eBl
Any info would be greatly appreciated

 

[KlausST]

Hi,

every LED (generally every electronic device) comes with a datasheet.
It tells you specifications about voltage and current of the LED.

With LEDs you need to know that they should be used in "constant current" mode. Don´t ever connect them to a constant voltage source without proper LED current limiting circuit.

If you can´t get the datasheet, then the source (supplier) of the LED is not reliable.
You can´t be sure that you get an identical LED on next buy.

***
You just have the chance to do some tests to find out the LED´s operating values:
Assuming the "3W" specification is correct.
* be sure to have correct heatsink for the LED
* you need a variable power supply, a 10 Ohms resistor with >1W power rating and a voltmeter
* 10 Ohms conected in series with the LED, connected to the supply
* slowly increase voltage until LED becomes alight, but not too bright (ensure not to overlaod the LED).
* then measure the voltage across the LED --> V_LED.

Then calculate the expectable current: I_LED = 3W / V_LED

Not to overlaod the LED I recommend to do further calculations/tests with only 80% of the calculated LED current.

Klaus

 

[dziubym]

Klaus,
Thank you for the info. I will do the tests as described.
The LED were bought from China and the datasheet was not provided.
On the other sight for similar LEDs I found
3Watt / White / 6000 K-6500 K / 260LM-280LM / 2 * 30mil chips / 120-140 degree Emitting Angle
Input(DC): 600mA-700mA / 3V-3.4V (Best Match with "Chanzon 600mA Constant Current LED Driver")
But probably datasheet should has much more information

 

[KlausST]

Hi,

Input(DC): 600mA-700mA / 3V-3.4V (Best Match with "Chanzon 600mA Constant Current LED Driver")

... but there are also 3W LEDs specified with about 10V and 300mA.
You can´t be sure.


Klaus