Battery Isolator and Switch (another post about them!)

[Foxtrot]

At one point, my Chevy had dual batteries in it. To start, I'm curious to know if this is a factory feature? It is a camper special and the second battery tray and solenoid (isolator) seem to be original from first glance, but I can't find anything that confirms this.

I want to put dual batteries back in and understand the basics of it all, but can't really decide what type of setup will fully suit me. I don't use it to haul a camper. Instead I want to use a dual setup so I never have to ask someone to jump my truck again (headlights get left on every few months) and to power a ham radio or other small electronics (like phone chargers).

What's the best solution for me? Just a battery isolator? Any recommendations for relay-style isolators--I kind of want a specific switch for the dual batteries, but it's not necessary I don't think?

You've got an empty battery tray in your truck, a disconnected old relay, a ham radio and a habit of leaving your lights on once in a blue moon. What do you do?