Help with LED light control Reef-pi

[ryangonzalezrz]

Hello everyone, I'm trying to set up the light control for my homemade lamp, where I use 3 W LEDs in a series of 3 connected to a 12 V source. The diagram of the connection board for the reef-pi is as shown in the photo, it happens that the LED does not turn off completely, always remaining very dim and it does not reach the maximum power it should reach if it were not on the board next to the MOSFET.

I'm using the P55NF06L mosfet and a 1k 1/4 resistor to connect the gnd board to the mosfet. Does it work like that or did I do something wrong? I tried to follow the tutorial in the "reef-pi Guide 5: Light Controller" topic. Could anyone help me?

 

[ryangonzalezrz]

I checked that the resistor was wrong and put it on by connecting the gnd to the gate input, but it continued in the same way, the LED was not at full power nor was it completely off.

 

[ryangonzalezrz]

Look at the difference in power between the LED connected to the MOSFET and the one connected directly to the power supply, and the lighting will vary.

Also, how the LED looks with the reef-pi configuration at zero

Can someone help me on how to do this control correctly?

 

[oreo54]

Hello everyone, I'm trying to set up the light control for my homemade lamp, where I use 3 W LEDs in a series of 3 connected to a 12 V source. The diagram of the connection board for the reef-pi is as shown in the photo, it happens that the LED does not turn off completely, always remaining very dim and it does not reach the maximum power it should reach if it were not on the board next to the MOSFET.

I'm using the P55NF06L mosfet and a 1k 1/4 resistor to connect the gnd board to the mosfet. Does it work like that or did I do something wrong? I tried to follow the tutorial in the "reef-pi Guide 5: Light Controller" topic. Could anyone help me?

As a discussion starter I believe you need a logic level MOSFET.
Your gate voltage of 5 or 3.3 is too low to " open" the mosfet all the way .
Now this is just "as I understand" it.

Standard levels are typically driven with 10 to 15 V gate pulses.

Key Difference between Logic level & Normal Level Mosfet

Hi I want to know the key difference between logic level & normal level Mosfet and also share the selection reason & criteria of both mosfet over the each other. Regards Lucky Kumar

community.infineon.com

Also typically with 3 leds in series you need a terminating resistor on the string of 3 since 12v is " generally" too much voltage ( 4v/ led will allow more current to flow than you want)
Yea they are bright at 12v ...too bright.
A general curve. Many blue 3w LEDs are rated at like 3.7v max.

Initial guesstimate in series w 3 3wleds that have a V(f) rating of 3.7, 12v ps

You will need 1 x 1.3 ohm 1 watt resistor.