Originally Posted by
Portlandflyer
In my opinion you want to be able to turn on the backup to be able to check to see if it's working. I have hundreds of flights using the Jeti BEC driving high voltage servos. My backup system is a Tech Aero PLR5 set at 6.2 volts with a 350 ma 2 cell lipo.
http://www.tech-aero.net/plr5
I check both sides every flight. I turn on the backup regulator first. When the servos kick in, I turn it off and plug in the main flight pack. When the BEC kicks in the servos, I turn the backup regulator back on.
I use a similar setup along with Jeti telemetry and alarms. Part of my preflight is to run thru the switch sequences you described (I use a Jaicco PerfectSwitch/2s Lipo backup regulator set slightly lower than my Jeti ESC BEC primary) and verify the Rx bus voltages on my Tx display for each along with alarms prior to heading out to the flight line.
You quickly get used to the '2 switch preflight', but if the OP wants a switchless solution, it is possible as to do as well.