Beginner Question about what Voltage to supply to LED driver.

Hello everyone,

I belive this probably is a very simple question, but all researching online has not brought up anything I would understand.

So:
I would like to build my own little dimmable underwater lighting system with a Cree high power LED

THIS is the LED I want to use.

Now, I know I need a driver that has an PWM input so I can dimm it with the arduino.

I thought about using THIS LED driver.

Now my only real question is the following:
Lets say the single color LED need 3.4V and a current of 700mA. If I use 2 I still have 700mA and 6.8V

I need to run the system on my 12V board system - can I just use anything from 11-14.5V strait into the MeanWell driver as long as my input voltage is higher than the sum of single voltages of the LEDs in row? Can I still give it a 100% working cycle or do would that mean the LEDs will receive whatever I have as input voltage?

I know this may seem a very stupid question, but I would really appreciate a brief explanation.

Thanks!

Great job supplying us with the product :slight_smile: Most newbie "forget".

Sme_1986:
If I use 2 I still have 700mA and 6.8V

If you can place the leds in series, yes. And it looks like this module has anode and cathode of each light broken out (6 wires) so you can.

Sme_1986:
can I just use anything from 11-14.5V strait into the MeanWell driver as long as my input voltage is higher than the sum of single voltages of the LEDs in row?

Yes. Or even better, up to 56V isn't a problem for the driver.

Sme_1986:
Can I still give it a 100% working cycle or do would that mean the LEDs will receive whatever I have as input voltage?

You can, the driver will limit the current to the max current. Don't think about controlling leds with a voltage. You set a current and the voltage is just a result of the applied current. The mentioned 3,4V is just a estimate of the voltage when you apply 700mA so you know what voltage you need to at least supply to the driver (+ the difference due to inefficiency) and the driver will limit the current thus knocking down the voltage (because it's a step down type it can only increase the voltage).

Thanks a lot for your great reply. This finally answered all my questions!
Perfect :slight_smile: