I'm very happy with Castle Edge Controllers, have a look on my setup guide.
viewtopic.php?f=17&t=1364To sum up the system on bigger birds, I use external BEC and OptiPower ultra guard to backup System Power, I do not trust on any internal BECs anymore.
To make it bullet proof:
A) I use a 20A Schottky Diode from Main battery to external BEC to prevent any return current (in case of main Battery failure, power might get from BEC HV side to ESC to drive Motor or if ESC burns there is a short).
B) if ESC requires Plus(red) on ESC connector, I do add a 2A fuse to protect System Voltage (if ESC blows up, any shorts inside can happen, like 50V from Battery or Power draw path for Motor as on Main Power side)
I wanna make sure, System Power (RX, FBL, Servo) stays up to get save on ground.
I learned my lessons well on different Setups with different ESC, Burning ESC causing over voltage on Servos, RX and FBL or even over current out of OptiPower and blow up due to ESC failure. I did end up with this specific wiring, with the Diode, a fuse and external BEC. So fare with this setup and the CC Edges, I had no bigger issues in the last 300 flights at least on Power side.