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I've always thought (and been told) to wire the ground wire to the chassis. But recently, I have seen negative battery terminals with wire inputs. Is it better to wire the ground directly into the negative terminal on the battery?

Thanks.

Thanks. So really, the negative battery terminals are to upgrade the short wire from the negative terminal to the chassis?

Some installers insist on ensuring a minimum resistance exists and will upgrade the connection from the negative terminal on the battery to the chassis.

Additionally, it is always best practice to ground all devices to the chassis with as short a wire as possible. The car is the LARGEST cable/surface area in the car. Use it to your advantage.

Jlos

hahaha I deleted my post by accident...umm I would say that theoretically going straight to the negative terminal would provide the best connection, but at the same time you're having to lengthen the ground wire which could cause interference issues in some vehicles. But yes, basically what you're doing is bypassing both the vehicle's chassis and that wire from the chassis to the negative terminal.

Obviously if you were gonna go straight to the negative terminal I'd use the biggest friggin wire you could get your hands on posted_image

Here's that link again if anyone needs it:

https://www.eatel.net/~amptech/elecdisc/battgrnd.htm

I actually had a question that my boss brought to my attention. Does the power cable and the ground have to be the same gauge? Should they be? I always thought the bigger the ground wire the better. The setup was a little more confusing than this, but basically I had a 4 gauge ground running to an amp with a 8 gauge power. Should it have been a 8 gauge?

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Sean Cawby
Midway Electronics
Rensselaer, IN
219-866-3716

Hey Sean, the gauge of the wires do not HAVE to be the same. Each installation will differ from car to car. What I mean by this is if the location of the ground is less than 36 " then use the same gauge, but if you have to extend the ground to reach for a good absolute grounding point, then use larger gauge for the ground. Hope this clarifies things for you and the big guy posted_image

. As well it is totally up to the isntaller wether he/she wants to install a larger gauge wire for ground.

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Jeff
Velocity Custom Home Theater
Mobile Audio/Video Specialist
Morden, Manitoba CANADA

The ground connection doesn't have to be any better than the power connection. The same current is flowing anyway. Running a ground cable instead wouldn't hurt. But why bother when you can just go to the chassis? Either way, the voltage drop in the wire (or across the chassis) will be only a very small fraction of a volt.

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2009 Pontiac G8 in planning stage
HU: ?
Speakers: ?
Amps: ?

Jeff, so what if it's less than 36" away? Should you have the same gauge, or would it still be fine to have a larger gauge?

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Sean Cawby
Midway Electronics
Rensselaer, IN
219-866-3716

If the length is less than 36" then having the same gauage wire should suffice...... depending on the rated amperage of the system of course. If you are using an 8 gauge wire for an 1000 watt system, then you are too small a gauge for the power and chances are the ground would also be too small. Use the chart here: https://www.the12volt.com/info/recwirsz.asp for your referrence.

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Jeff
Velocity Custom Home Theater
Mobile Audio/Video Specialist
Morden, Manitoba CANADA

I understand the recommended wire sizes, but my boss gave me crap for putting a 4 gauge ground which was about a 3 foot run to an amp that only had a 8 gauge power wire. I think the amp was like maybe 400 watts. I didn't have any specific sources to argue with him at the time, so I thought I'd get on here and make sure I was right.

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Sean Cawby
Midway Electronics
Rensselaer, IN
219-866-3716

I think your boss was looking at the $$$ amount rather than the fact that you installed a better ground. I always say, better safe than sorry.

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Jeff
Velocity Custom Home Theater
Mobile Audio/Video Specialist
Morden, Manitoba CANADA

Well I kind of doubt that since his words were something like.... "Come look at this, you did do one thing wrong..."

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Sean Cawby
Midway Electronics
Rensselaer, IN
219-866-3716

Using a thicker wire than needed doesn't hurt, he probably was just being cheap. There's no reason that they need to be the same gauge as long as both are thick enough for the current.

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2009 Pontiac G8 in planning stage
HU: ?
Speakers: ?
Amps: ?

there is absolutly nothing wrong with running a larger ground wire. however, never ever use a smaller power wire than your ground wire would be.

also, there would be no advantage to going straight to the negitive terminal on your battery unless there is no other place to mount your ground.

You could/should have just stuck with an 8awg ground. He was probably mad because you wasted good wire. But, in my opinion, use the same size ground as the power wire unless you have to extend your ground pretty far.

Well, I did it for 2 reasons. 1) It was about a 3-4 foot run.... which is not a big deal, but also 2) the install just looked nicer with the 4 gauge. I had to run two ground wires (we were fresh out of d-blocks, bossman forgot to order more) for the amps. Even after explaining that to my boss (who by the way isn't even certified, and I am), he still said you have to use the same size ground wire.

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Sean Cawby
Midway Electronics
Rensselaer, IN
219-866-3716

Ground Wire