RV DC Grounding

TAS CPA

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Going from original batteries and WFCO Converter/Charger to Multiplus II and Lithium batteries. My confusion right now is related to the original grounding/white wires related to the original converter and DC panel.

There are two white wires that disappear into the underbelly of the travel trailer.

One is the original chassis/earth ground from the shell of the original WFCO. The second comes from the DC panel and disappears into the underbelly.

This second wire, per the WFCO diagram goes to the existing battery negative. NOPE. Existing battery negative is bolted to the RVs frame and there isn't a single grounding wire other than that at the original battery location.

So, my first question is: When running the wires from the new lithiums (Lynx Distributor) to the DC panel. Do I run the negative wire all the way to the DC panel, and tie all of those white wires together and assume that they are grounding on the RVs frame?


Second question: I already have two items needing chassis grounds: Multiplus and Lynx/Shunt. Is one chassis ground wire a good practice? Meaning, run the Multiplus' ground to the Lynx, then run a wire from the Lynx/shunt to the chassis?

Thanks!
 

smoothJoey

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Please provide pictures...
One of the ac/dc distro panel with the cover removed.
If the converter is not inside the distro panel please provide a picture of it as well.
Also inlude a picture of the battery bay.
There may be a junction box near the battery bay, if that exists please provide a picture of the box with the cover off.
If there is anything else notable include a picture of that as well.

Clarification: I meant the legacy battery bay but may as well show the old and new locations.
 
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TAS CPA

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OK, here are some images that should help. Original equipment converter/charger and batteries are gone, so you won't see those.

Converter1 v1.jpg
Green circle was Converter case ground wire. It disappears into belly of RV.
Orange Circle wires: Black is positive feed to DC panel. White is converter negative and goes to a bus bar in the DC panel.
Yellow wire comes from DC bus bar (same as converter negative) and disappears into belly of RV
 

TAS CPA

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Here is the DC panel. Same box/area as AC wiring panel.

DCpanel1_LI.jpg

Orange circle is the Positive Black wire from the original converter.
Pink circle is the Red wire that runs up to the original battery.
Yellow circle. Can't really see it from this image, but there is a bus bar in back that both of the white wires (converter negative to panel, panel negative to ????) terminate.
White wire in lug at top of image is just a pigtail coming from the bus bars in yellow circle.

DCpanel2.jpg
 

TAS CPA

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Original battery location had only two 6awg wires. The red wire coming from the DC panel lug, and a white wire that ran from the battery negative to the frame.

BatteryGround1.jpg
This white wire ran from battery negative to the frame.

InkedBatterypositive1_L1.jpg
Red wire ran to the post that's circled, but still hard to see. That post then fed battery.

There is a lot of other stuff going on up here, with the 7 pin wiring getting connected to the trailer wiring, power and grounds for all the 12v slides, jack, etc.. The plan is to just bus bar all those so I don't have to run all new wires. So, there will still need to be a DC power feed to the front of the trailer! But, the batteries will now be at the rear of the trailer.
 

TAS CPA

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Here's the area under the bed that will now house the new utilities.

There will ultimately be 4 batteries feeding the Lynx power in. Lynx, Shunt, Lynx Distributor. Fairly straightforward on this end...other than my question of how to treat the grounding to the chassis.

NewUtility2.jpg

NewUtility1.jpg
 

grizzzman

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That Power center appears to be a WFCO. That wire on mine that wire connects to the frame. The red wire is connected to a self resetting breaker. none of it maters if the power center is removed?(unless you are doing any 120 volt bonding there.)
 

smoothJoey

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What we haven't seen is the connections between the tow_cable, original battery and running gear.
Luckily your dc panel has a dc busbar and the branch circuits have return wires.
 

TAS CPA

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That Power center appears to be a WFCO. That wire on mine that wire connects to the frame. The red wire is connected to a self resetting breaker. none of it maters if the power center is removed?(unless you are doing any 120 volt bonding there.)
Not trying to remove the power center. In fact my goal is to keep it and minimize the number of wires I need to pull to that location.

For that location and those wires, the one wire I just don't know where it goes is the white wire (yellow circle in post #3). WFCO manual shows it goes to the batter, but there is no white wire running to the battery other than from the frame of the RV.

Any ideas on how to test/figure out where that goes. Removing the underbelly of the RV is not a simple task.
 

smoothJoey

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Not trying to remove the power center. In fact my goal is to keep it and minimize the number of wires I need to pull to that location.

For that location and those wires, the one wire I just don't know where it goes is the white wire (yellow circle in post #3). WFCO manual shows it goes to the batter, but there is no white wire running to the battery other than from the frame of the RV.

Any ideas on how to test/figure out where that goes. Removing the underbelly of the RV is not a simple task.
Use a fox and hound.
 

TAS CPA

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What we haven't seen is the connections between the tow_cable, original battery and running gear.
Luckily your dc panel has a dc busbar and the branch circuits have return wires.
Yeah, that's all gone. The were all just tied together with twist ties.

None of the white wires in this picture are even close to the 6awg from the DC panel. All were in one monster twist tie with a pigtail, and that pigtail had the frame ground shown in the photo.

White.jpgYellow.jpgRed Blue.jpgGreen.jpgBrown Black.jpgBlack.jpg
 

smoothJoey

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Yeah, that's all gone. The were all just tied together with twist ties.

None of the white wires in this picture are even close to the 6awg from the DC panel. All were in one monster twist tie with a pigtail, and that pigtail had the frame ground shown in the photo.
Are you planning on making this trailer road worthy?
If yes are you planning any integration with the house system?
 

TAS CPA

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Are you planning on making this trailer road worthy?
If yes are you planning integration with the house system?
Yes, has to be road worthy. 7 pin to trailer wiring will be cleaned up and reattached. Just won't be a battery up at the front of the trailer.
 

smoothJoey

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With that, if I get continuity between the positive coming from the DC panel and the chassis, can I assume that the white wire that is supposed to go to the battery is in fact just tied to the frame?
Which white wire?
Specificity is required :)
 

TAS CPA

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Which white wire?
Specificity is required :)
The one that is supposed to go to the battery. It is circled in yellow, post #3. Comes from the bus bar in the DC panel then disappears into the belly of the beast, never to be seen again.
 

smoothJoey

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Yes to both. All systems need to work with the new lithium install.
The trailer brakes need a battery.
The trailer brake battery and the running gear get their power from the 7 pin tow cable.
You don't want your house batteries drawing or sending beaucoup current over the tow cable.
Would you consider keeping the systems isolated?
 

smoothJoey

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Here is my map created from your pictures.
Its a work in progress and be warned my clerical skills suck.
Code:
some_hole {
    green circle {
        white {
            ground
            converter.eg<->probably to the frame or to the original battery
            remove
        }
    }
    orange circle {
        white {
            negative
            converter.neg<->dc_panel.neg
            remove
        }
        black {
            postive
            converter.pos<->dc_panel.pos
            remove
    }
    yellow circle {
        white {
            negative
            dc_panel.neg<->probably to the frame or to the original battery
            ?
    }
}
dc_panel {
    yellow circle {
        white {
            negative
            dc_panel_busbar<->dc_panel_board.neg
            remove
        }
    }
    orange circle {
        black {
            positive
            dc_panel.neg<->converter.neg
            remove
        }
    }
    pink circle {
        red {
            positive
            dc_panel<->original_battery
            ?
        }
    }
}
original_battery {
    no circle {
        red {
            positive
            original_battery<->breaker<->dc_panel.pos
            ?
        }
        white {
            negative
            original_battery<->frame
            ?
    }
}
 
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