Trouble connecting mosfet with pixhawk

Hello guys, this is my first time posting here. I generally use ROVs (underwater drones) and with them ardusub firmware on a Pixhawk 2.4.8. Lately I’ve been working on putting some accessories on the ROV, those accesories have to be controlled by an on/off switch, in this case I am using an IRF 520 mosfet module, so I connected the Pixhawk aux port 6 (GPIO) with the mosfet module but the problem is that when I give the signal from the aux port 6, the mosfet module does not turn on, the gate is not opening completely, the mosfet module only delivers like 2 V to the accesory and should deliver 12 V. I checked the signal on the aux port 6 and seems OK, delivers like 3,27 V but at the beggining of the mosfet the signal decreases to approximately 2,4 V.
Also I realized that the gate opens fully when the pixhawk has few ports in use and does not work when it has all the ports in use ( we added gripper, lights and more thrusters).

The IRF 520 gate threshold voltage is min. 2 V and max. 4 V

I think that maybe could be the amperage.

I made the circuit with the IRF 520 because I think it fits well in there but any advice will be great received, maybe it can be replaced by a relay.

I hope you can help me,
have a good day and thanks.

Hi, probably not the amperage problem :thinking: Your mosfet THRESHOLD max voltage is 4V so you need at least 4V to be sure it opens fully.
Consider other mosfet with lower threshold or use additional transistor.

Thanks, I’ll keep it in mind.