I am a computer systems administrator and I've don't basic work on my car but haven't done anything significant with car electrical.
I have an overland/adventure truck I'm building with a battery bank and DC DC charge controller that draws power from the car and solar. I can forsee a situation where I need to charge my batteries and don't want to put wear on my cars engine.
My solution is to get/build a 12v output generator with electric start that will be automatically turned on when the batteries are low, so I need to connect this behind the DC DC charger on the car alternator side to handle the input amperage
On a basic level, will connecting the 12V 50A+ generator output to the car battery terminals where the DC DC charger does damage the car electronics in any way over long term use.
In an accidental emergency will both alternators running in parallel cause any damage and how could I prevent this without installing a physical switch.