grounding wiring

[clarity413 10+ year member]

I heard that wiring the negative wire directly to the battery instead of to the body is better. Is this true? Why?

I went ahead and bought the extra negative 1/0 wire when I got it from welding supply because of consistancy. Also, I don't want to have any problems with the chasis ground I'd rather just run the extra wire.

I read a couple posts somewhere a couple months ago that having the wire direct to the battery will help make the system sound cleaner and prevents other ground loop problems.

Honestly, I can't think of a reason where it'd be better other than consistancy. It wasn't that much extra for the wire for me because weldingsupply's 1/0 wire is about 1$ a foot... it was only 16 extra dollars anyways.

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[bass maniak 10+ year member]

ground it to the chassis........keep the ground wire as short as possable.

 

[Acidburn 5,000+ posts]

according to a MECP Master Installer i recently spoke with, ground it to the frame

 

[Gauntlet 5,000+ posts]

Your amp is indirectly grounded to the negative terminal of your battery as it is, so it makes no sense to run 15 extra feet of wire to accomplish the same thing that 2 or 3 feet will do.

 

[clarity413 10+ year member]

yah, the only problem with that is I'm going to be running about 200 amps of audio stuff and all the stock stuff is using the chassis ground including the 170 amp alternator. I have a 1/0 battery to chassis wire and now that I think about it I'm not sure if I want to run the risk of that wire burning up. It's only about a ft but still it'll have about 400amps going through it or it could rather

 

[JimJ 5,000+ posts]

It's only about a ft but still it'll have about 400amps going through it or it could rather

where are the other 200 amps coming from? If you have 200 amps of audio equipment, then that's your current draw...no more.

 

[monte_carlo97 10+ year member]

what about grounding to the chasis and also run a wire to the neg of the battery from that grounding point.

 

[Gauntlet 5,000+ posts]

Why in the world would you want to do that? The battery is grounded to the chassis. The amp is grounded to the chassis. Hence, the amp is indirectly grounded to the battery. As long as both connections are on bare metal and have the same potential, there is nothing to worry about.

 

[JimJ 5,000+ posts]

Why in the world would you want to do that?

about the only reason is noise suppression - directly connecting it to the battery introduces the least amount of noise into the system...which is why it's standard practice in two-way radio installs. In audio equipment, however, the differences are less noticable.

 

[forbidden 10+ year member]

And the genius's of the world who assume it is the correct way to wire a ground always tell you to run it as short as possible (people have been known to be wrong). Most do not take the time to measure the resistance on the ground return. (most installers are payed by the job and want the next vehicle in the bay). While their arguement is that the chassis of the vehicle has way more metal or surface area to carry current through, the flip side to it is that this current has to travel through really crappy weld joints, glued together unibody panels and crappy recycled metals, all which adds resistance to the most important connection in the system - the ground wire. If the ground point you choose in the rear of the vehicle is below 1/2 ohm I would use that as a ground point. If it above this reading I would then upgrade all of my grounds up front (a good idea to do anyhow) and then check the reading again. If it is still too high, then I would be grounding to the battery.

 

[clarity413 10+ year member]

where are the other 200 amps coming from? If you have 200 amps of audio equipment, then that's your current draw...no more.

the other 200 is a guess at how much with the lights, 170 amp alt, radio, all the other electronics that are grounded to the chassis

 

[Acidburn 5,000+ posts]

a normal car would probably never pull more than 60a with everything on

 

[monte_carlo97 10+ year member]

And the genius's of the world who assume it is the correct way to wire a ground always tell you to run it as short as possible (people have been known to be wrong). Most do not take the time to measure the resistance on the ground return. (most installers are payed by the job and want the next vehicle in the bay). While their arguement is that the chassis of the vehicle has way more metal or surface area to carry current through, the flip side to it is that this current has to travel through really crappy weld joints, glued together unibody panels and crappy recycled metals, all which adds resistance to the most important connection in the system - the ground wire. If the ground point you choose in the rear of the vehicle is below 1/2 ohm I would use that as a ground point. If it above this reading I would then upgrade all of my grounds up front (a good idea to do anyhow) and then check the reading again. If it is still too high, then I would be grounding to the battery.

That is why i suggested to do what i said. Then no matter what you are sure to have a good ground.

 

[JimJ 5,000+ posts]

a normal car would probably never pull more than 60a with everything on

if that. Why are you including the 170A alternator in your current draw calculation? That's what's supplying the power, not pulling the current...you could have a 300A alternator, only pull 60A from it, and use 8awg for it. Am I making sense...don't know if I am //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[clarity413 10+ year member]

Does the power from the battery come back from the alt to the battery? I'm sure there is some kind of resistance. I'm not sure, I'm a computer science major not an engineer. I think I'm just going to run the extra negative wire because I already bought it. From all the posts I think it's just optional but won't hurt anything. Thanks!