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Battery bank is in the back passenger side. Where is the best/safest place to ground the electrical system?

Seen some advise using this larger bolt hole above the wheel well.

Thanks
Depending on your planned amperage, and even just to be safe, I recommend using a pillar. I know the d-ring holes are used, but the path from the sheet metal in front of those holes to the chassis is questionable in my view. Grounding directly to a pillar means you're going right into thick steel with solid weld points leading to the rest of the chassis. Here's a look at my 2/0 ground on the driver's side c-pillar. There's also a smaller spare 8AWG ground that terminates here (just a backup; it's un-used now). Everything flows through the 2/0 now as it should.
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The little oem hole on the left top is where I previously had a very small ground. It's no longer used and is now painted over.

Some points: buy a jar of no-ox-id from amazon, and after sanding away all paint from the pillar steel, apply a very thin coat of it to all exposed metal.

For the bolt, you can just use stainless since most of the current is passing through the direct contact between the lug and the pillar steel. At the time I did this I used copper bronze hardware, which Schneider Electric likes, but I later swapped it for stainless. The bolt really shouldn't and doesn't need to carry any current in a proper ground.

Star lock washers are recommended for electrical, but I used a nord-lock and a nyloc on the backside. Typically you wouldn't use nylocs with electrical, but with a beefy 2/0 cable and the relatively reasonable current levels I expect to push (at 48V), there's very little chance the nyloc will ever reach 200F (melting point). Even if it does, the nord-lock is still there, and it's the better fastener anyways.

The wires are wrapped in Tesa heat tape, which was mostly to offer abrasion resistance.

Cheers.
 

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So I think we are speaking the same language. But can you confirm this is what you mean. I was going to ground my entire electrical system by running a cable from the negative bus bar to the chassis. Probably to the bolt hole above the wheel well.
As @Boondox suggests in his reply, if you're "floating" the house electrical, the chassis ground isn't part of the system - just somewhere for things to go if it goes bad, more or less. But if you're doing DC-DC, that's totally different. And some DC-DC is a shared ground; others are isolated. Bit of options in there... 馃
 

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View attachment 173784
View attachment 173785
Battery bank is in the back passenger side. Where is the best/safest place to ground the electrical system?

Seen some advise using this larger bolt hole above the wheel well.

Thanks
I have been using that exact bolthole
for the past year, and it works great. Grind all the white paint off down to bare metal and put a big all metal washer over the top of the wire. Then put some Dielectric grease on it, and you're all set.
 

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Battery bank is in the back passenger side. Where is the best/safest place to ground the electrical system?

Seen some advise using this larger bolt hole above the wheel well.

Thanks
I used the tie down bolt hole just above the wheel well where your batteries are. Ground off the paint, fastened 1/4" copper bar across the area ground out and bolted the 4/0 battery ground to that using the tie-down bolt hole through the copper. Run a Victron 2000 watt converter that's been in service for about a year with no problems. My largest appliance draw is an 1800 watt induction burner in the galley.
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