Truth?

[tommyk90 5,000+ posts]

9 times out of 10 the chassis is the better ground...

I wouldn't say the odds are that high.

A chassis ground will suffice for most setups, but any really high power applications (4000+ watts) would most likely benefit from a dedicated ground wire to the front battery/alternator.

Trying to pull 500-600 amps through shitty sheet metal and a steel frame isn't exactly efficient.

 

[BEAVER.989 10+ year member]

I wouldn't say the odds are that high.
A chassis ground will suffice for most setups, but any really high power applications (4000+ watts) would most likely benefit from a dedicated ground wire to the front battery/alternator.

Trying to pull 500-600 amps through shitty sheet metal and a steel frame isn't exactly efficient.

The sheet metal and chassis are a much better conductor in most cases due to the sheer size advantage they have over a "small" wire. Less resistance, pure and simple.

 

[SethPhillips 5,000+ posts]

The sheet metal and chassis are a much better conductor in most cases due to the sheer size advantage they have over a "small" wire. Less resistance, pure and simple.

waaaaaay more resistance in the unibody of a car....

 

[BEAVER.989 10+ year member]

Every car is different. As fiberglass and plastice body panels becomes more and more common, more cars would be better served by using a battery ground.

BUT, in solid cars that are still built primarily with METAL, I believe chassis grounds are superior.

 

[ultimate157 5,000+ posts]

I'd take a cable of copper over unibody steel any day.

if car audio is your "life", then I TRULY pity you

Because that's exactly what I said? //content.invisioncic.com/y282845/emoticons/confused.gif.e820e0216602db4765798ac39d28caa9.gif

 

[PaulD 10+ year member]

Did you fail to notice that you are on a car audio website? //content.invisioncic.com/y282845/emoticons/confused.gif.e820e0216602db4765798ac39d28caa9.gif

Yes, and I call this a HOBBY ...... nothing more. It keeps me off the streets //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

The difference is, I may try things and fail at it .... but's it's better than having no life at all. With the post counts/month for some of you guys, I wonder wen you have time to actually install/enjoy your system.

I enjoy trying to help people out when I can but most of this stuff you guys are discussing ( > 90% ), I already knew like 15 years ago so honestly I don't learn much - unfortunately. I can also (usually) tell when someone is just regurgitating stuff they heard but do not really understand it.

I tend to read in a few other forums that seem to havea higher percentage of SQ people, as opposed to - how hard will this hit, how can I annoy others from a block away kinda stuff. Just my personal preferences of the way I like my system. Well ...... back to the car, I don't think it will ever truly be finished.

 

[Louisiana_CRX 5,000+ posts]

the best ground on the vehicle is its source the source starts at the battery......plain and simple...for instance fresh water comes from the spring not the end of the creek.....

 

[Lakota 5,000+ posts]

He's completely right... Who DOESNT know that rusty steel mixed with a shit ton of alloys, paint, and other extremely good conductors are much better than pure copper. God all of those welds, multiple body panels sure don't get in the way at all.
But seriously, grounding to the battery is the best solution.

I'm running my amp down to 0.5 with 1/0 grounded to the battery and have zero dimming. Using the body as my ground was just terrible, even at a higher impedance. yes the spot was completely bare, and my battery had an upgraded ground as well.

x2

You might as well use a dedicated run and go straight to the battery because in the end that's where the current loop is completed. Either way the battery ground is part of the circuit, but doing a dedicated run will allow a better path for the current.

 

[Lakota 5,000+ posts]

Every car is different. As fiberglass and plastice body panels becomes more and more common, more cars would be better served by using a battery ground.
BUT, in solid cars that are still built primarily with METAL, I believe chassis grounds are superior.

Superior over a piece of ideal wire that has no paint, welds and or multiple connections? Each time that there is a new connection through the body (pieces of metal overlapped) there is a sum of voltage drops. Although these drops may be small, they do add up and are less ideal than a single piece of wire.

 

[njaykaplan 10+ year member]

Out of curiousity, I have a unibody car with the stock battery in the trunk. The stock batterys been gone for a long time, and i have a supply of a couple orbital batterys and a kinetik 2000.. I replaced the stock ground with some knu wire, the cheapest 0 gauge i could find //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif, and it runs to a bolt in the side.. no paint, just steel.. For running 3-4k, is that sufficient for a ground? From a 150 amp alternator, i don't get a WHOLE lot of dimming and stays in mid 13s, but I currently lack a DMM to really test resistance and see if i have the best available ground.

 

[mil81 10+ year member]

Yes, and I call this a HOBBY ...... nothing more. It keeps me off the streets //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif
The difference is, I may try things and fail at it .... but's it's better than having no life at all. With the post counts/month for some of you guys, I wonder wen you have time to actually install/enjoy your system.

I enjoy trying to help people out when I can but most of this stuff you guys are discussing ( > 90% ), I already knew like 15 years ago so honestly I don't learn much - unfortunately. I can also (usually) tell when someone is just regurgitating stuff they heard but do not really understand it.

I tend to read in a few other forums that seem to havea higher percentage of SQ people, as opposed to - how hard will this hit, how can I annoy others from a block away kinda stuff. Just my personal preferences of the way I like my system. Well ...... back to the car, I don't think it will ever truly be finished.

What forum do you find best for SQ setups. I have been thinking about searching for one lately.

 

[mil81 10+ year member]

Superior over a piece of ideal wire that has no paint, welds and or multiple connections? Each time that there is a new connection through the body (pieces of metal overlapped) there is a sum of voltage drops. Although these drops may be small, they do add up and are less ideal than a single piece of wire.

Do you think there are many of those "new connections" in most vehicle bodies? If they have good welds in these locations, don't you think it would even out?

The way I think about it, having a large ground plane should conduct better than a small wire (provided there aren't many new connections) and draw less noise.

 

[Lakota 5,000+ posts]

Do you think there are many of those "new connections" in most vehicle bodies? If they have good welds in these locations, don't you think it would even out?
The way I think about it, having a large ground plane should conduct better than a small wire (provided there aren't many new connections) and draw less noise.

The more connections you have the more potential for voltage drops. Yes, there are quite a few connections in most cars because the entire body of a car is not a single piece. I don't understand what you mean by "evening out"? Think of these connections as a small resistor, when they are combined the resistance is increased. Now think of a single wire with zero connections between the ends; there would be no resistors for a voltage drop.

Yes, the body of a car is quite large compared to a piece of wire, but the steel of a car is a mediocre conductor compared to copper. 1/0 is often times rated for currents of 300A or so and you can continue to do multiple runs of it unlike you can with the body. Have you never noticed that those who draw a shit load of current , like many of the cars in dB drag, highly prefer to do runs over the car body?

 

[mil81 10+ year member]

The more connections you have the more potential for voltage drops. Yes, there are quite a few connections in most cars because the entire body of a car is not a single piece. I don't understand what you mean by "evening out"? Think of these connections as a small resistor, when they are combined the resistance is increased. Now think of a single wire with zero connections between the ends; there would be no resistors for a voltage drop.
Yes, the body of a car is quite large compared to a piece of wire, but the steel of a car is a mediocre conductor compared to copper. 1/0 is often times rated for currents of 300A or so and you can continue to do multiple runs of it unlike you can with the body. Have you never noticed that those who draw a shit load of current , like many of the cars in dB drag, highly prefer to do runs over the car body?

Dude, you need to look at where I'm from. LOL. I'm from northern BC, and there are few competitions, and no big builds like you guys see down there. I am just trying to theorise, and brain storm. I'm not arguing either, just trying to figure stuff out.

I'm sorry, that was worded poorly. I think, if they did a long enough weld, rather than just a spot weld, that there should be no reistance drop. Welding actually bonds the metal.

I'm sure a 1/0 ga. wire would be a better conductor for pulling high power. As you stated, most of the big DB Drag guys are running it. How about when it comes to a SQ situation? As I stated before, a large ground plane like the chassis would pick up less noise than a wire ran through the entire vihicle. Or would the noise picked up be too small to hear?

 

[Lakota 5,000+ posts]

Dude, you need to look at where I'm from. LOL. I'm from northern BC, and there are few competitions, and no big builds like you guys see down there. I am just trying to theorise, and brain storm. I'm not arguing either, just trying to figure stuff out.
I'm sorry, that was worded poorly. I think, if they did a long enough weld, rather than just a spot weld, that there should be no reistance drop. Welding actually bonds the metal.

I'm sure a 1/0 ga. wire would be a better conductor for pulling high power. As you stated, most of the big DB Drag guys are running it. How about when it comes to a SQ situation? As I stated before, a large ground plane like the chassis would pick up less noise than a wire ran through the entire vihicle. Or would the noise picked up be too small to hear?

Although I do not compete in SQ, I would think that a run of wire would still be better since the copper is a better connection. I can check with some of the guys that do SQ in MECA to give you an answer or hopefully some SQ guys will chime in on this thread.