Stupid wiring question

[daplatapus]

OK, so I built my LED light and used a Dim4 board to get sunrise/sunset. But... because the LED's still light up at 0V they don't really ramp up. I put the drivers on a timer so they come on instantly (albeit at 10% but it's still quite bright) then they ramp up from there. Is there a way to put in a resistor or something to kill that 10%? So that when the timers kick in, the drivers putting out 10% are still not putting out enough to actually light the LED's yet? SO I guess in theory you'd only get 90% output of the LED at max even though the driver is putting out 100%

Smack me if that doesn't make sense, my electrical knowledge is almost 0 :P

[Cal_stir]

unfortunately thats the nature of leds, you could set the timers so 1 set lights at a time, but what I did was got 4 blue pods for my RKE and I start them 30 min before the leds and ramp them up for 30 min, the pods start out very dim and you hardly know when the leds kick on.

[martinmcnally]

Originally Posted by daplatapus

OK, so I built my LED light and used a Dim4 board to get sunrise/sunset. But... because the LED's still light up at 0V they don't really ramp up. I put the drivers on a timer so they come on instantly (albeit at 10% but it's still quite bright) then they ramp up from there. Is there a way to put in a resistor or something to kill that 10%? So that when the timers kick in, the drivers putting out 10% are still not putting out enough to actually light the LED's yet? SO I guess in theory you'd only get 90% output of the LED at max even though the driver is putting out 100%

Smack me if that doesn't make sense, my electrical knowledge is almost 0 :P

It depends on the driver. I'm guessing you are using inventronics drivers which start at 10%?

If you were to go with some MeanWells you will get true 0-100% dimming.

Your resistor idea would not work in series as a resistor will only step down the voltage across the LEDs not the current and its the current that is controlling the brightness. However a resistor placed in parallel would do the trick however you would have to do some experimentation to see what size of resistor would be acceptable.

[sphelps]

You could always add another small array of LEDs with either lower power or a different driver to come on first and ramp up to a point before the rest of the LEDs turn on at 10%.

[Cal_stir]

Originally Posted by martinmcnally

It depends on the driver. I'm guessing you are using inventronics drivers which start at 10%?

If you were to go with some MeanWells you will get true 0-100% dimming.

Your resistor idea would not work in series as a resistor will only step down the voltage across the LEDs not the current and its the current that is controlling the brightness. However a resistor placed in parallel would do the trick however you would have to do some experimentation to see what size of resistor would be acceptable.

My meanwells start at 5% which is fairly bright.

[martinmcnally]

Originally Posted by Cal_stir

My meanwells start at 5% which is fairly bright.

Hmm, what kind do you have?

[Cal_stir]

Originally Posted by martinmcnally

Hmm, what kind do you have?

ELN-60-48D

I use a RKE with an ALC for sunrise/sunset

[daplatapus]

Yeah they are inventronics. 2- 40W and a 25W. If I switch out to Meanwells you're saying I'll be able to ramp from 0% with the dim4 board?

Originally Posted by martinmcnally

It depends on the driver. I'm guessing you are using inventronics drivers which start at 10%?

If you were to go with some MeanWells you will get true 0-100% dimming.

Your resistor idea would not work in series as a resistor will only step down the voltage across the LEDs not the current and its the current that is controlling the brightness. However a resistor placed in parallel would do the trick however you would have to do some experimentation to see what size of resistor would be acceptable.