Can I charge the house battery with the engine alternator?

Hmmmm…. 2 pages of almost entirely wrong answers.

It’s a 1988 rig, it ran an old school continuous duty relay, AKA a Ford starter relay, on the drivers fender. One heavy lug to the alternator, one heavy lug to the house battery and the light lug goes to an ‘engine on’ circuit.

When you start the chassis the alternator is connected to the chassis AND house battery(s), when you shut off the engine house and chassis batteries are separate.

Any auto parts place $20…….