I am building my new Tarot 650 and have started experimenting with FPV which I bought from 3DR. I power my FPV camera and transmitter directly from my 3S battery. The image is transmitted correctly but as soon as I start the motors the receiver monitor turns black. When I power the FPV system from a separate 3S battery the image remains more or less stable.
As I would like to have everything powered from one battery I bought a BEC from Hobbyking that keeps the voltage at 12V with input varying from 7-21V. That didn't work either. Even with the motors powered off the screen was blinking all the time. A quick measurement showed that the output voltage was 10.66V instead of the promised 12V. I have returned the thing to HK and before I buy a new one I am just wondering whether it is feasible what I want? Is a BEC able to keep the voltage stable with all the spikes and changes in the voltage when the drone is flying?