I am working on a project to make a quadrocopter that can spray liquid material. Unfortunately, I had this problem: when I give full thrust and try to activate the water pump at the same time, the water pump won't respond. However, if I stop the rotors and then activate the water pump, it will work. What can cause this?
Flight controller: K++ Jivi
Voltage regulator: similar to this one
The water pump is being controlled by a voltage regulator that connects to the flight controller like a servo pin (for those who know this flight controller, the VR is attached to pin: EXT1 -> P2).