# Mean Well ELN 60

Hi Guys

I am in the design stage of making some home made aquarium lights. I plan to use cree xp LED's of different colours nd will use the arduino to control the lights. the lights will fade in in the morning to white, fade to blue in the evening and then fade off.

So if i have got things right, the above driver is a constant current device. this current is adjustable via a potentiometer called SVR2 which is inside. I understand that you size the driver by adding up all the forward voltages of each LED. the driver should be able to supply slightly more voltage.

If i go with the Mean Well ELN 60-48, the data sheet says it will deliver an LED operational voltage of between 24 and 48v. So question one is if the LEDs have a forward voltage of 3.3v, the driver will run between 7 (24 / 3.3 = 7.27) and 14 (48/3.3 = 14.54) leds. And that the driver will automatically adjust the voltage depending on the number of leds connected. Is this correct?

Question 2 is just a little further down the data sheet, it details in the Output section a voltage adj. range. the range of this adjustment is 43.2 to 52.8v. What is this and what does it mean?

Craig

cjm181:
If i go with the Mean Well ELN 60-48, the data sheet says it will deliver an LED operational voltage of between 24 and 48v. So question one is if the LEDs have a forward voltage of 3.3v, the driver will run between 7 (24 / 3.3 = 7.27) and 14 (48/3.3 = 14.54) leds. And that the driver will automatically adjust the voltage depending on the number of leds connected. Is this correct?

Yes.

PS: Minimum would be 8 - 7*3.3 is only 23.1

PPS: Many people prefer to put in a few meters of WS2811 LED strip - far easier to power and control than all that messing around with high power LEDs.

So what is the voltage adj range then?

I may go down that route. at the moment there are 2 floresent tubes in. So it is possible to use the LEDs to fade in. Once on the tubes come on and the LEDs go out. Reverse at off time. However the tubes are very bulky ontop of the tank. I like the relatively small bulk of leds. I plan on mounting them in a long heat sink of say 25mm wide.

However if i do use the cree xp individual LEDs, i then have to get around the water proofing?

kr
Craig

cjm181:
So what is the voltage adj range then?

As noted in the other thread: It's a thing you can fiddle with if the output isn't right.

i might be a little stupid, but i dont understand.

I thought the unit would automatically adjust the voltage depending on how many leds are connected. Lets use our example again,

if i connect 8 leds to the driver and if each led had a forward voltage of 3.3v, then the driver would have to supply 26.4v

The voltage adj range is between 43.2 and 52.8v. So the driver would be unable to drive 8 leds. Thats my point! if we use the led operation row we both agreed that we can power 8 to 14 leds.

So where does the voltage adj range come in and whats it for?

Kr
Craig

cjm181:
I thought the unit would automatically adjust the voltage depending on how many leds are connected. Lets use our example again,

Let's hope so.

cjm181:
So where does the voltage adj range come in and whats it for?

Only meanwell knows for sure.

Whatever it is, it's not worth losing sleep over (or creating two forum threads).