How can I find the maximum input voltage of a POWER LED ?

[Jestin_cubetech]

How can I find the maximum input voltage of a POWER LED ?

 

[hemnath]

What will be the voltage drop across your power LED?
For example: Whatever voltage you apply, Input voltage = Voltage drop across resistor + voltage drop across POWER LED.
Voltage drop across power LED remains the same(check the datasheet of the POWER LED). you have to consider only one thing, your resistor must have the higher wattage value. So that it can dissipate the power. So choose the resistor value with higher wattage when more voltage you applied at input.

If i'm wrong, PS correct.

Best wishes

 

[ArNvC]

Input voltage is not of concern for an LED. The forward current is what is very important. However, you can use the following formula to find the forward voltage of a LED:

V = (h x c) / (λ x e)
where h = Planck's constant
c = speed of light (m/s)
λ = wavelength of light emitted (meters)
e = charge on an electron (coulombs)

 

[Jestin_cubetech]

LED description says it is a 10W LED

above 9V LED start to glow, @12V it consume 180mA without a current limiting resistor.


LED looks like a square metal heat sink module. there are 8 small led segment.

similar image [except 9 led segment]

 

[ArNvC]

From the data you have given, with power rating 10W, its quite obvious the forward voltage is 8-9 V, as 8V power led's are quite common and may need a heat sink if not provided with it. Now the 8v led's have a forward current rating of around 1A to 1.6 Amperes max.

 

[Jestin_cubetech]

how can i get 10W at 12V input ?
it consume only 180mA !

 

[ArNvC]

Now, if it is not glowing at the brightest then it is surely of a high voltage rating, in that case current will decrease.

 

[Jestin_cubetech]

then How can I find the maximum input voltage of a POWER LED in practice ?

 

[ArNvC]

Really difficult considering the fact that you know only the wattage...however one of my friends told me that certain LED driver that he used for a similar 10W LED had 78 V 120mA output

 

[Jestin_cubetech]

thanks

can i use this driver
**broken link removed**

https://www.aliexpress.com/store/product/10W-LED-Driver-DC8-26V/904082_456050939.html

 

[ArNvC]

Well I opened the second link and found this in the Related Products links just at the bottom...

**broken link removed**

driving just a similar LED as you posted in the previous pic

 

[Jestin_cubetech]

this specification says
Output Voltage: DC10-12V, Current: 900mA


my LED current consume is 180mA @12V.
is it workout ?

 

[Audioguru]

The trouble with E-Bay parts is that they have no detailed datasheet.
The LED with 8 segments probably has four 3.2V to 3.8V LEDs in series and another 4 parallelled. Then it needs 12.8V to 15.2V. You don't know its actual voltage requirement.

As it heats its current increases if it is not regulated which makes it heat more which increases the current more until it burns out.