ground connection on frame structure?

[2StrokeDiesel]

I was poking around my newell the other day and noticed that the negative 12V comes off the battery and connects to the coach frame only and I assume is for grounding. Is this sufficient or should it be grounded from more than one location?

2strokediesel

[Newell Attack]

You will have more resistance with a chassis ground than if you added a - ground wire of proper size. Whether that matters in reality depends on the size of your converter, inverter, battery bank...etc.

[77newell]

On my 77 coach the ground from the batteries is bolted to the frame rails. One problem with this is the corrosion that can occur between the copper ground and the steel frame. Other than that it works just fine. There will always be a need for a ground to the frame since all the chassis stuff is grounded to the frame and it will not be worth the effort to run wires to all the chassis lights for instance. If the high amperage 12 volt house load grounds are connected to heavy steel frame members that are well connected through the frame then very low resistance will exist, so low that a cable would probably be no better. The only way to know if what you have is OK is to follow the steel path from the attachment point of the load (inverter or other heavy load) to the attachment point of the battery ground cable.

[GringoPhil]

On my 77 coach the ground from the batteries is bolted to the frame rails. One problem with this is the corrosion that can occur between the copper ground and the steel frame. Other than that it works just fine. There will always be a need for a ground to the frame since all the chassis stuff is grounded to the frame and it will not be worth the effort to run wires to all the chassis lights for instance. If the high amperage 12 volt house load grounds are connected to heavy steel frame members that are well connected through the frame then very low resistance will exist, so low that a cable would probably be no better. The only way to know if what you have is OK is to follow the steel path from the attachment point of the load (inverter or other heavy load) to the attachment point of the battery ground cable.

:dito: I'm with you all the way Jon, Your posts as usual are right on the money.

[77newell]

GringoPhil: thanks for the compliment. I used to teach aircraft system troubleshooting and also problem solving in a manufacturing environment. People here helped me when I first had my coach and I'm glad to return the favor when I can. We own very complex vehicles and if we are to solve the problems ourselves (and I certainly respect those that choose to have others do it for them) it really helps to have many minds applied.

I will add that as I construct my suggestions I do so in a way that I hope helps educate the reader on the thinking process of problem solving/troubleshooting. I believe the more we understand how to think about the problems the more problems we will be able to solve and the more proud we can be of ourselves for what we can do.