Grounding and DC Returns

[TimberGRV]

Hi All,

I'm in the process of replacing my batteries with lithium along with a solar and Victron install. I'm pretty solid on almost all of the install, but find my self questioning the grounding process, especially after seeing how GD installed the stock components. I'll try my best not to muddle AC grounding, DC returns, and bonding.

Currently, from what I can see, the electronics are "grounded" in five locations. The ATS, inverter, and converter all have a solid bare copper wire grounded to the chassis. In the same area, a bus bar filled with what I figure are the DC returns from the breaker/fuse panel also has a wire from it bolted to the chassis. In the front compartment, the battery negative, along with the returns from the levelers pump and a handful of other DC components, are all bolted together to the chassis.

As part of my install, the stock batteries will be removed from the front compartment and the new batteries, along with the Victron components, will be installed in the basement next to the ATS and circuit panel back. The new inverter and charge controller will have their cases grounded to the negative bus bar on a Lynx Distributor. A single ground from the Lynx Distributor negative will then be bonded to the chassis.

My concern is what others have described as "ground looping". With this setup, I will have a single ground from all of the new components, however the ATS will still be grounded to the chassis, as well as the busbar of DC returns from the fuse panel and the DC returns in the front compartment which are each separately bolted to the chassis. For the latter, my assumption is they will be using the chassis as the DC return. My question is, should I eliminate these two locations where the DC returns are bonded to the chassis and instead run dedicated lines from them to the new negative busbar? My concern is if I have multiple locations where the system is connected to the chassis that it could somehow get energized in the event of a short.

And what about the ATS ground? Is that ok to stay connected to the chassis or should I relocate that to the negative busbar as well?

Thanks in advance for everyone's help.

-Tim & Amber

[Redapple63]

Hi All,

I'm in the process of replacing my batteries with lithium along with a solar and Victron install. I'm pretty solid on almost all of the install, but find my self questioning the grounding process, especially after seeing how GD installed the stock components. I'll try my best not to muddle AC grounding, DC returns, and bonding.

Currently, from what I can see, the electronics are "grounded" in five locations. The ATS, inverter, and converter all have a solid bare copper wire grounded to the chassis. In the same area, a bus bar filled with what I figure are the DC returns from the breaker/fuse panel also has a wire from it bolted to the chassis. In the front compartment, the battery negative, along with the returns from the levelers pump and a handful of other DC components, are all bolted together to the chassis.

As part of my install, the stock batteries will be removed from the front compartment and the new batteries, along with the Victron components, will be installed in the basement next to the ATS and circuit panel back. The new inverter and charge controller will have their cases grounded to the negative bus bar on a Lynx Distributor. A single ground from the Lynx Distributor negative will then be bonded to the chassis.

My concern is what others have described as "ground looping". With this setup, I will have a single ground from all of the new components, however the ATS will still be grounded to the chassis, as well as the busbar of DC returns from the fuse panel and the DC returns in the front compartment which are each separately bolted to the chassis. For the latter, my assumption is they will be using the chassis as the DC return. My question is, should I eliminate these two locations where the DC returns are bonded to the chassis and instead run dedicated lines from them to the new negative busbar? My concern is if I have multiple locations where the system is connected to the chassis that it could somehow get energized in the event of a short.

And what about the ATS ground? Is that ok to stay connected to the chassis or should I relocate that to the negative busbar as well?

Thanks in advance for everyone's help.

-Tim & Amber

First Tim, I see this is your first post, de welcome to the forum. Lots of great questions.

I am currently doing a similar upgrade sans the already installed GD Inverter and ATS, however, that is the approx have seen. Mine is similar.

My battery positive goes to a bus bar on the chassis (always live 12v), then loops back to the coach cutoff, then back to the switch. From there goes back to that bus bar (different spot) to provide switched service to the converter.
The battery negative is directly grounded to chassis.

From what I can tell here are the items fed continuous unswitched 12v:
Stabilizing jacks
Emergency brakes
Tongue jack
Trailer Brakes

Mine is. Travel trailer so it may differ from a fiver with a hydraulic setup, and those that have either a residential fridge with inverter and solar or 12v with solar.

My plan was to feed my batteries first to 400 amp t-fuse, then to a Blue Seas 6006 switch. From that switch branch off to the direct 12v devices on current GD bus bar going through a 60 amp amp fuse. Then the output of that 6006 switch to my Victron Lynx.

On the negative side, first through the Victron smart shunt, then to the Victron negative side of the Lynx.

I plan to run a fairly beefy chassis ground to the Lynx. Then you run pos and neg of the other devices to the Lynx on that end (Hub and spoke).

On the other end (it does seem there is no cable running from my dc distribution box, it is grounded to chassis there, so rather than run a second wire all the way to my Lynx, I will ground to chassis there. I would prefer to have them nice and lined up, but I do believe this is acceptable but not desirable. There are others who definitely will respond that have far more experience than I.

On Edit: I tried to add a picture, but for some rerason I am getting an error message that it is an invalid JPEG. Once I get it sorted, I will post, or I can PM it to you.

Picture added



Bill

[Scott'n'Wendy]

You can treat the trailer frame as a negative bus bar.
Looping is a concern with A/C systems with neutral and ground.

[Soundsailor]

On Edit: I tried to add a picture, but for some rerason I am getting an error message that it is an invalid JPEG. Once I get it sorted, I will post, or I can PM it to you.

Bill

The forum is currently having difficulty handling images, management has been alerted.