I'm installing a stereo in an RV and would like to maintain default behavior of having the stereo receive power on vehicle accessory power/ignition, but also be controlled by a switch in the RV for use when the vehicle is not in use. These are the requirements:
When the RV switch is OFF, the stereo turns on and off with vehicle accessory power.
When the RV switch is ON, the stereo remains powered regardless of vehicle operation.
The source of power when the vehicle is running does not matter, but it must utilize the RV batteries when it isn't.
Would there be any problems with utilizing a ~30A 5 pin relay to achieve this? The stereo utilizes an external amp, so it will be drawing very little power.