Switch Relay for 12V/24V 50A for switching between battery and PSU


I am upgrading my charger box for my helicopters with an Arduino to control the PSUs. So thats because I writing here, as I have a basic question. I am looking for a solution to disconnecting the PSUs if a battery is connected.

So I like to use the 12V battery for control line and also for power supply. The relay has to handel up to 24V and 50A.

12V--->Relay Trigger
--->Relay Power 1

24V--->Relay Power 2

I think i need a changeover relay from automotive?


If you are manually conecting the batteries, why not use a switch to disconnect the PSU?