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Chassis Ground Location?

Soiboughtavan

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Joined
Jul 12, 2021
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Hello!

I'm curious about the ground location for my system. Can I run a 4/0 Awg wire to the location marked in green on the photo depicted? Also, how do you recommend connecting it to the metal frame of the van?

Another thing I'm curious about is ground my inverter. The Renogy 2000W pure sine has a ground connection for a 10 awg wire. Do I run that to my negative power bar? Or should I ground it separately to another location on the vehicle chassis.

I know the wiring isn't the most tidy. I was having a heck of a time settling on locations for all the components.

Wiring Diagram Final Draft.jpgSolar Forum Ground Chassis.jpg
 
My unibody B250. I sanded the paint away to bare steel. I used solder to plate the bare metal. Then used a bolt to fasten the cable to the metal body. The connections have been fine for three years. I test all my connections for voltage drop during maintenance. I also connect the negative BusBar to the metal body. Else, the case lug connections, ("ground"), don't do shit. Having the chassis connect to the negative BusBar I can tap any place on the chassis.
I think the 4/0 cable is overkill, but with dc, bigger can be better. Note this for the 8AWG.
Your power board looks good. You need more fuses at the positive BusBar. I do not like circuit breakers.
 
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My unibody B250. I sanded the paint away to bare steel. I used solder to plate the bare metal. Then used a bolt to fasten the cable to the metal body. The connections have been fine for three years. I test all my connections for voltage drop during maintenance. I also connect the negative BusBar to the metal body. Else, the case lug connections, ("ground"), don't do shit. Having the chassis connect to the negative BusBar I can tap any place on the chassis.
I think the 4/0 cable is overkill, but with dc, bigger can be better. Note this for the 8AWG.
Your power board looks good. You need more fuses at the positive BusBar. I do not like circuit breakers.
Thanks for the suggestion! Very helpful. Any reason behind not digging the circuit breakers?
 
Unless that ground carries a lot of amps by design... I believe #8 is fine. 4/0 is crazy big unless the inverter negative uses the frame. Other components with a chassis ground lug should also have a direct connection to the vehicle chassis.
 
Some basics for best performance:

Low voltage negative should be a large current carrying cable equal to the positive.

All connections should be clean and solid.

Ideally, DC negative and AC ground (green or green/yellow wire) should go to a common bus bar and be attached to the chassis at one single point with one good large cable. It'll still work if you don't do this, but you you might have some minor issues down the line.

You absolutely can mix voltages on the negative/ ground side as they should all be the same "reference" voltage, if you have multiple voltages at play.

You cannot and must not mix voltages on the positive side. This one seems obvious to most people, but after pointing out the previous I've had folks ask.

And last but not least, under no circumstances should the "hot" and "neutral" wires of the AC be attached to the chassis or be allowed to come into contact with it at any place other than a neutral/ground bond which ideally will be managed by your inverter. If you don't know what that means, consult an electrician with experience in mobile AC applications.
 
My studied opinion. DC circuit breakers are fine on sub-circuits as would be found on a fuse block. Generally under 30 amperes. >Most DC breakers are directional. >Breakers introduce another point of voltage drop, ie; Two connections for a fuse plus one more, the contact points, for a breaker. >>A large catastrophic short could send enough amperes to weld the contacts together. >Breakers being mechanical are subject to mechanical failure.
These problems are rare in quality breakers such as BlueSea. But they still exist and have caused trouble.
>Always remember Rule #1; Fuses, or breakers, protect wires.
All battery cables, battery to BusBar, negative and positive, must be the same awg, or be >fused to the smallest gauge. If using Chassis to negative BusBar, use the same size as the battery negative.
 
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