Poor man's build-in generator for long box AF865/811(?)

There’s no “dirty” 12V power, it’s DC. It’s not ideal for charging only because it isn’t regulated to lower its voltage when it senses less load, like a “smart” charger does.

This generator install definitely needs an exhaust system. Sure it’s a generator compartment but the sets its designed for aren’t portables. Even if fumes aren’t an issue, heat will be.
With a fan and an exhaust I think it could work out fine.
Exhaust is tricky if you have to be able to easily remove the set to fuel it though.