switching

Hello everybody,

I have a set of battery, but I only one hooked up to the circuit, The
other one act as a backup. I want to implement an electronic unit that
will change (swap) the batteries.Therefore the wiring will need to be
changed. The circuit need to sup****t 5amp of continuous current. Here
is what I want to implement.
from:
A to C
B to D

to:
A to D
B to C

Is it better to use a analogue or digital switching approach. I am
just worried that digital might take too much energy by keeping those
transistor or mosfet open and close.

Li