Do you ground battery negative terminal to chassis?

[Boyntonstu]

Just wondering of you follow the vehicle's pattern of grounding the Negative.

If you ground, there will be less wire Voltage loss.  This is because whatever gauge wire you choose there will be a round trip loss due to the resistance of the wire if you do not ground the Negative and instead use a second Negative wire.  Twice the loss of using a single Positive wire.

 

[Gideon33w]

Mixed bag in my experience. I've had my house power grounded to the chassis and not.
The issue is that two vehicles were fine with it and another reacted badly.
No noise on ground but one of the vans just didn't like it for some odd reason.
Now, if you develop noise (volts) on the chassis ground you will run into issues if solar is using the same ground.
Personally, I prefer to keep every sub-system as separate as possible.

 

[WalkaboutTed]

I have my batteries grounded to the chassis. No fiberglass anywhere. I also have smaller grounds scattered around because I have so much stuff: Fantastic vent fan, 4 LED lights, six 12v outlets, 10 USB outlets and the portable solar input. My inverter is grounded to the batteries.

I was worried about a ground loop, but I put filters on the TV and cell phone booster and don't have any noticeable interference. I guess if I had a ham radio, there might be some, but I have no plans in that direction.
Ted

 

[BradKW]

My 12 volt, 24 volt, and 110 systems are not grounded... All are separate from the vehicle starting batteries. I really wish somebody could explain to me why using the vehicle chassis as a common neutral ever became referred to as "grounded" when it is actually anything but.
I also wish somebody could explain how using the vehicle chassis as a common neutral and calling it grounding is actually somehow safety-related. Especially when you hear about people accidentally electrifying their entire chassis shell went on Shore power.

 

[Weight]

This is about DC. My house bank negative is connected to the chassis. My heavier loads, charging and inverter, have dedicated negative returns to the main negative buss. I sanded the paint to shinny steel where I made the chassis connections. I then used solder to 'tin' the area where the cable connects. Then the main negative chassis connection is insured to be low resistance. While 'electrical ground' officially means 'at the potential of the earth', general use has expanded to mean the negative or sometimes the positive, side of a battery connected as a common return path to said battery.
This is about 120 volt ac. If your 120ac is connected to the pedestal. Your chassis is not connected to the green wire. Your toaster oven cord has a short to the chassis. The breaker will not trip. The chassis will be hot to earth, and you will complete the circuit when you stand on damp ground and touch the skin of the vehicle. The chassis should always be connected to the green wire when getting power from the pedestal. And yes, 120 volts can kill you.
If the vehicle shell is 'hot to ground' when on shore power, something is wrong with the green wire, most likely at the pedestal, but if you don't maintain your shtuf, the problem could be your vehicle 120vac wiring.

 

[highdesertranger]

yeah 12 and 24v DC systems do not have neutrals. they have a positive and a negative. people connect the negative to the chassis to save wire. that way you are only running one wire in most cases. you do not run the risk of shock with low voltage DC. the negative on DC is often mistakenly called ground it is not a ground, you only have ground in an AC system. highdesertranger

 

[speedhighway46]

For 120 VAC, read the National Electric Code regarding floating neutrals. In short (pun intended) NEVER connect the white neutral wire to the system ground in a mobile installation. Only the green "ground" wire should be connected to ground.

 

[BradKW]

Weight, what exactly is the pedestal?

Sent from my Pixel XL using Tapatalk

 

[Almost There]

Brad - it's one of these!

http://www.rvparksupplies.com/p/503020AMPPEDPOWER/

Basically it's any shore power hook up.

 

[speedhighway46]

AT mentioned the pedestal, or any typical shore power hook-up: this is the location where the white neutral and green ground are finally tied together in 120 VAC systems. This location is the initial point in a mobile application where there is a "true" ground; usually a long rod driven into the ground.

 

[Weight]

No. Not at the pedestal or shore connection. The white neutral and green ground should only be tied together at the entry point from the grid. That is the main panel. There is still an ongoing argument about floating neutrals on generators.
On DC battery it is by custom to refer to the return path as ground, even if it is not earth ground. British refer to it as earth on DC battery systems. ;( Language is not always perfectly defined. T. Jefferson had "no use for a man that only knew one way to spell a word".

 

[John61CT]

More clear to just say negative return.

For expensive gear or high currents I would never use chassis for return. Two wires, same gauge and length.

Device cases "needing grounding" yes to chassis.

And yes chassis tied to engine and negative busses.

 

[Weight]

It is not necessary to have positive and negative return the same length. They probable be near the same as both go to battery (buss). But the real object is least voltage drop, that is the least distance as possible. If the means + or - are different lengths that is not a bad thing. Positive and negative return are both the same linear circuit, make it as short as possible. Inter connections on multiple batteries are a different problem. Those negatives should be the same as the other negatives and positives to positives. But positives do not need to be the same as negatives. Return, negative, earth, ground. It all means the same to all when talking about a dc battery system. Even John understands what is meant.

 

[John61CT]

For expensive gear or high currents I would never use chassis for return. Two wires, same gauge and length.

Ask Victron, Magnum, MasterVolt engineers, hooking up one of their big inverters or kombi units.

Personally even a little $800 fridge I'd do it that way, or close as practical if busses involved.

 

[Weight]

So, are you saying the negative and positive must be the same length? Then you are wrong.

 

[Boyntonstu]

So, are you saying the negative and positive must be the same length? Then you are wrong.

Rewire you automobile with 2 wires in order to make the positive and negative wires the same length?

My car's electronics don't mind the negative ground and its unequal length wires.

 

[highdesertranger]

the positive and negative must be the same length when you need a balanced system like wiring batteries in series. in other cases not so much.

you only need to run critical loads all the way to the battery, like inverters, refrigerators, and the like. you can use chassis grounds for noncritical loads. highdesertranger

 

[WalkaboutTed]

I guess in an ideal world, that would be better. My world ain't ideal and wasting all that wire for equal length runs wasn't gonna happen for me. As many wires as I have, probably only two out three are the same length.

I haven't noticed any ill effects. I think that what's more important than anything else is that every circuit is fused.
Ted

 

[Boyntonstu]

the positive and negative must be the same length when you need a balanced system like wiring batteries in series.  in other cases not so much.

you only need to run critical loads all the way to the battery,  like inverters,  refrigerators,  and the like.  you can use chassis grounds for noncritical loads.  highdesertranger

"you only need to run critical loads all the way to the battery,  like inverters,  refrigerators,  and the like. "

Is your statement based on facts or theory?

Is you car audio system as critical as a refrigerator?  Does it have a chassis ground?

 

[Weight]

My radio uses less than 2 amps. It is quiet when the ground fails. My refrigerator is fused for 15 amps. The beer gets hot when the ground fails. My inverter uses up to 200 amps. It don't want to hear about a chassis ground.