Most of the larger airplanes are using a simple approach, which is very reliable, and has the least amount of failure points. And that is to use two batteries, two switches, and plug each one independently into a port on the receiver. Its simple, redundant, with the only failure rates being very rare occurrences.

Using a battery backup system is probably the second most used solution. The only difference is there is only one connection to the receiver. This allows a failure of the connector, the wiring, or the battery backup itself to cause a complete failure of the power system. Not as rare as the dual battery/switch setup, but fairly close.

Either of these two setups will work well. I prefer the simplistic method, since there is no circuitry involved, and that improves its overall reliability.

Here is one link with lots of reference information

http://www.rcuniverse.com/showthread...hreadid=424119

I rarely see anyone flying the larger planes with a single switch and battery. It seems rather rare these days..