This dual battery system is designed to use an external battery independently of the internal one.
Switched operation means that while we use one battery the other is disconnected, so we have an independent battery circuit.
We use one and when it runs out we change to the other. This system is done by switching connector.
It is the most reliable system since it does not modify or mix electronics. It would be like removing a battery and inserting another, but in this case without removing the internal one.