I started planning my RV-14 panel starting about a month before I ordered the empennage kit. It's an ongoing obsession to perfect the panel, especially the switches, to make every possible situation a left-to-right flow that is not error-prone. That leads me to ponder the options for the switch to control the backup battery (I plan to have a single iBBS that will feed the essential parts of the G3X Touch-based panel along with alternate trim and alternate flaps switches, which allow you to bypass all electronic control of the pitch trim and flap motor and connect them through panel-mounted momentary switches fed directly from the backup battery).
It seems that most people have a main battery switch and a separate backup battery switch. My thought is to use a single switch with 3 positions: OFF, AUX, MAIN. When in the OFF position, both the main and backup batteries will be disconnected. In the middle AUX position, the backup battery will be activated. In the MAIN position, both the backup battery and the main battery contactor will be activated. This way saves a switch and ensures that you can't turn on the main power of the airplane without having the backup battery on and ready. You also are less likely to forget the backup power on when you turn off the plane. The arguable disadvantage is that you have to touch the same switch twice during the before-engine-start check list: Once to turn on backup power and observe the EFIS booting and a second time to turn on main power.
Please poke holes in my idea before I spend the $43 on a SP3T MS25201-4 switch instead of $24 to get two SPST MS35058-22 switches.
It seems that most people have a main battery switch and a separate backup battery switch. My thought is to use a single switch with 3 positions: OFF, AUX, MAIN. When in the OFF position, both the main and backup batteries will be disconnected. In the middle AUX position, the backup battery will be activated. In the MAIN position, both the backup battery and the main battery contactor will be activated. This way saves a switch and ensures that you can't turn on the main power of the airplane without having the backup battery on and ready. You also are less likely to forget the backup power on when you turn off the plane. The arguable disadvantage is that you have to touch the same switch twice during the before-engine-start check list: Once to turn on backup power and observe the EFIS booting and a second time to turn on main power.
Please poke holes in my idea before I spend the $43 on a SP3T MS25201-4 switch instead of $24 to get two SPST MS35058-22 switches.