# What kind of Driver to use for my 5 Watt SMD LED

##### Newly Enlightened
Hey There!

First a bit of a context:- I am totally new to this SMD LED stuff. I have no Idea what kind of Drivers to choose or anything like that in this regard. So please bear with me here.

I want to build a 20 Watt LED Light Fixture for my Planted Aquarium.

I have got these 5 Watt SMD LEDs here (Four of them following the simple math - 4x5=20). I do not know any technical specifications of this but All I can see is that there is written X17-20 and 0502 on the PCB its attached to.

Also there are a total of 10 small Illuminating things inside that big yellow circle (I saw these when I tried hooking one of them to a driver I had Lying around with an Output of 12.22 Volts at 0.5A which equaled to 6.11 Watts which is bit higher than the LED though the LED Lit very dim).

So I really do not understand what drivers should I use to achieve the maximum brightness out of it. How to hook them up together to achieve what I want.

Can I use any of these lying around? Yes or No? and Why?

How do I do calculations of the drivers for my future projects and builds.

#### Zak

##### Enlightened
LEDs require a certain amount of voltage, termed "forward voltage" to be able to pass a given amount of current. More voltage is required for more current, and the curve is a little different for each LED. You'll need to know the approximate forward voltage of the LED to match a power supply to it.

If you have a way to deliver known amounts of voltage while monitoring the current flowing through the LED, you can determine this yourself. If not, you'll probably need to identify that emitter and find its datasheet.

##### Newly Enlightened
LEDs require a certain amount of voltage, termed "forward voltage" to be able to pass a given amount of current. More voltage is required for more current, and the curve is a little different for each LED. You'll need to know the approximate forward voltage of the LED to match a power supply to it.

If you have a way to deliver known amounts of voltage while monitoring the current flowing through the LED, you can determine this yourself. If not, you'll probably need to identify that emitter and find its datasheet.

Okay let me arrange those.

##### Newly Enlightened
LEDs require a certain amount of voltage, termed "forward voltage" to be able to pass a given amount of current. More voltage is required for more current, and the curve is a little different for each LED. You'll need to know the approximate forward voltage of the LED to match a power supply to it.

If you have a way to deliver known amounts of voltage while monitoring the current flowing through the LED, you can determine this yourself. If not, you'll probably need to identify that emitter and find its datasheet.

I went to the shop again from where I had bought these LEDs and this was the Sticker on the carton of LEDs

I guess this Means 15~17 Volts at 300mA each which means if I am to make a 20 watt Fixture with 4 of them in series then I will need an adapter with 15~17 Volts at 1.2 A. Right?

Where Can I look for a driver with this efficiency​

#### DIWdiver

##### Flashlight Enthusiast
Close, but no cigar. If you wire them in series, the voltages add, current stays the same. If you wire them in parallel, the voltage stays the same and the current adds. So 4 in series is 60-68V, 300mA, 4 in parallel would be 15-17V at 1.2A.

If you arranged them 2 in series, 2 in parallel (total of 4 LEDs), that would be 30-34V at 600 mA. That last driver you show looks quite promising with max 45V and 570mA. I'm not sure why it says it's only for LED Tube Lights. I'd want to know more about that before saying for sure that's okay.

if you google "constant current LED transformer" you'll get lots of hits. You want one with a voltage range that includes your setup's voltages, and a current that's not higher. One that's dimmable down to your current would be usable, but you'd have to be careful not to turn it up too high. That may be the only way to get exactly the current you want, as most seem to be in increments of 350 mA.