Originally Posted by rcers
My other recommendation - always disable BOTH bec's for twins and use a separate BEC or another LiFe battery for the airborne system.
I have watched MANY crashes on twins where one ESC BEC was not enough. MANY.
If you are flying a smaller sized model like the C-310B Cessna by Alien Aircraft, and your ESC BEC's are of the switching power supply type, the use of both BEC's along with the isolating diodes should work well. A club member had this setup in his twin 2500 watt (each) electric jet, using two 100 Amp Castle Creations ICE ESC's with their uBEC's. That diode setup worked out well.
That said, I would NEVER use a linear type BEC on any model with more than two LiPo cells in their battery pack. The risk is to high.
For the larger models, what works well is the Castle Creations 10 Amp uBEC, along with a two cell A123 or LiFe backup battery. My two setups (running 2400 and 3000 watts) now have over 200 flights total on them, with complete success.
Take a look: