Grounding house batteries

[Sikafishn]

Probably a dumb question but do I have to ground the house batteries to the frame when:
1. Charging off solar panels 
2 Charging off alternator
3 Both

 

[Weight]

Solar panels to the controller are not usually negative return to the chassis. Controller to the battery could be chassis connection, along with a negative cable. Alternator will be negative return to chassis even if using a separate negative to the alternator. My system has the house bank negative with dedicated return wires, as well as negative to the chassis.

 

[John61CT]

Yes full round-trip negative return wires are most reliable over time.

I would not use chassis for negative return for anything high-current or important/high-cost/sensitive.

But the bank negative should also be "grounded" to engine block & chassis, house circuit at other multiple points is fine.

All of the above applies to DC only.