[BusNit]

In my quest to identify what goes where and how for my upcoming Lithium house battery project, I found this doohickey. Looks like it would be powered on with another switch to cut off power to the inverter but I can't find said switch. Am I correct to think this is some sort of electric cut off switch? Top wire goes to inverter bottom tied wires go to separate battery banks for inverter. Ultimately, I need to figure out how to isolate house from engine since each will have its own battery chemistry. Also when I shut off Aux battery switch in electric panel of engine compartment, I still get power to inverter and said solenoid. Thought those would shut off but they don't. My digital voltmeter at dash does lose power.