davidfre21
5,000+ posts
Is just a lil racist...
find a bolt in ur trunk some where, above wheel well is where i found mine... sand it and then put it there
n2audio
5,000+ posts
OPTIDRIVEN
You're just introducing un-needed resistance in the current path. It's not the end of the world, but the shorter it is, the better.
helotaxi
5,000+ posts
Kilroy was Here
Really? Which has lower resistance, 10 feet of OFC cable or the 8 2-3mm tack welds between your amp grounding point in the trunk and the battery/alternator ground under the hood?
n2audio
5,000+ posts
OPTIDRIVEN
OMG dude.
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Clearly you have no idea how a car is put together. The resistance of a car's chassis is practically immeasurable.
But if you feel it necessary to run an extra 10' or 15' of ground wire for the fun of it -- who am I to stop you??
helotaxi
5,000+ posts
Kilroy was Here
Where does the battery typically ground? One of the pieces of sheetmetal under the hood. Where do you ground the amp in the trunk? A piece of sheetmetal. Are they the same piece? No. What is between them? Several other pieces of metal all held together by tack welds. At every joint, the current must travel through the tack welds. Now which is a better conductor OFC or steel? How can a length of OFC that reduces the amount of steel in the ground path possibly ADD resistance?
Never said it was necessary, but assuming that the wire is of the correct gauge, it will not hurt anything having that run of wire, and he certainly will not be worse off.
maylar
10+ year member
Electrical Weenie
Battery wires to fender... fender connects to body through steel bolts that rust and corrode... body becomes part of trunk through tack welds...
If every point in a car chassis was exactly the same potential, there'd be no such thing as "ground loops". Even millivolts of difference can create alternator whine (believe me, I know). If someone wants to go through the effort of running a dedicated ground wire to the battery, I wouldn't stop him.
If every point in a car chassis was exactly the same potential, there'd be no such thing as "ground loops". Even millivolts of difference can create alternator whine (believe me, I know). If someone wants to go through the effort of running a dedicated ground wire to the battery, I wouldn't stop him.
n2audio
5,000+ posts
OPTIDRIVEN
The battery is one of the worst places for electrical noise. Think of all the accessories that are grounded there - or near there.
If your only battery ground goes to sheet metal you need to get a new car - your starter is drawing a couple hudred amps through that sheet metal every time you turn the key. Pray your car doesn't go up in flames the next time you start it.
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My 1988 ford has over 20 stock grounds. Battery to FRAME -FRAME to BLOCK - and many other misc. smaller gauge.
Please guys - this is car audio 101.
What you're arguing would be much the same as claiming the world is indeed flat.
If your only battery ground goes to sheet metal you need to get a new car - your starter is drawing a couple hudred amps through that sheet metal every time you turn the key. Pray your car doesn't go up in flames the next time you start it.
//content.invisioncic.com/y282845/emoticons/rolleyes.gif.c1fef805e9d1464d377451cd5bc18bfb.gif
My 1988 ford has over 20 stock grounds. Battery to FRAME -FRAME to BLOCK - and many other misc. smaller gauge.
Please guys - this is car audio 101.
What you're arguing would be much the same as claiming the world is indeed flat.
mulisharider10
10+ year member
Low Co. Motives
so, u guys are all wrong. If u have a ground that isnt ne where near ur car, it still works. try it, hook up a power supply from the battery, then hookthe ground to something big and metal(not ur car). it still works. Isnt that wierd. Try sometimes and them maybe u will understand that as long as u get a good ground, everything is good.
helotaxi
5,000+ posts
Kilroy was Here
Well everything has to go back to the battery, so technically everything is grounded there. However I have never heard of battery whine, or battery noise. Ground loops on the otherhand I have heard of and they are caused by differences in potential between audio components. Running a ground straight to the battery is lowering voltage drop and lowering the resistance, and grounding all your audio components that way will eliminate ground loops.
My whole car is made of sheet metal, it's called a uni-body. And my starter doesn't not start the car if the voltage drops .3 volts. My starter isn't subject to noise from a ground loop. Fire is not the concern, voltage drop is.
Well maybe you should take a 200 series car audio course, you know get past the basics of just how to get everything to turn on and look at how to get it to work at its best.
n2audio
5,000+ posts
OPTIDRIVEN
I'd like to compliment you on exceedingly high levels of both ignorance and confidence.
First I'd like to piont out -- resistance is the CAUSE of voltage drop. Resistance leads to voltage drop, whcih - when there's enough of it - creates heat - which explains my mention of fire - in an extreme case.
Having said that --
Your car's body has less resistance than any reasonably sized piece of copper. Outside of running a 4/0 wire for ground -- the chassis is the best ground for an amp - period.
If what you're saying is right 99% of the best competitors and technicians out there are doing it wrong.
Hopefully you'll find and understand the facts sooner or later. It's pretty clear I'm not going to get through to you.
First I'd like to piont out -- resistance is the CAUSE of voltage drop. Resistance leads to voltage drop, whcih - when there's enough of it - creates heat - which explains my mention of fire - in an extreme case.
Having said that --
Your car's body has less resistance than any reasonably sized piece of copper. Outside of running a 4/0 wire for ground -- the chassis is the best ground for an amp - period.
If what you're saying is right 99% of the best competitors and technicians out there are doing it wrong.
Hopefully you'll find and understand the facts sooner or later. It's pretty clear I'm not going to get through to you.
helotaxi
5,000+ posts
Kilroy was Here
Yes, I know what causes voltage drop.
If there were no interceding welds and bolts I would completely agree with you. Problem is I have yet to see a car made of one single piece of metal. Have you measured the resistance from your amp ground point to your battery's negative post? Then measure the resistance of your power wire going from your battery to your amp. Which is less? Is the difference huge? No, but there is a difference.
I never said that one way was wrong. I just said that there is better. The original question was whether having a ground cable running to the front of the car and grounding near the battery is bad, you said yes, I said no. Steel is not as good a conductor as copper. Electrical current will take the path of least resistance. Copper wire to the battery is that path. More copper less steel is better than the other way around. Tell me where I am wrong. I am perfectly willing to accept facts, but myths that have worked their way into being accepted as fact because "that's just the way its done" but have no basis in fact I refuse to follow blindly.
If you had something better than "that's the way its always done" I'd be more than happy to listen to you. Until then...
n2audio
5,000+ posts
OPTIDRIVEN
You sound fairly intelligent - I can't believe you see it this way.
Sure steel is more resistant - but you can use the least conductive metal on the planet and get perfectly good current flow through it as long as the cross sectional area is sufficient. Which explains why the chassis is better than a relatively small piece of wire.
Have I ever measured the resistance of my car's chassis? No - I don't have equipment large enough, or accurate enough to measure thousandths of an ohm. Those who have that equipment however, will indeed tell you a car's chassis is less resistive than running a dedicated ground wire of reasonable size. That is a fact.
Go to carsound - read - that forum is full of engineers and audio tech's and a couple of the elite car audio engineers in the country.
I'm sorry you find this so difficult to believe.
Sure steel is more resistant - but you can use the least conductive metal on the planet and get perfectly good current flow through it as long as the cross sectional area is sufficient. Which explains why the chassis is better than a relatively small piece of wire.
Have I ever measured the resistance of my car's chassis? No - I don't have equipment large enough, or accurate enough to measure thousandths of an ohm. Those who have that equipment however, will indeed tell you a car's chassis is less resistive than running a dedicated ground wire of reasonable size. That is a fact.
Go to carsound - read - that forum is full of engineers and audio tech's and a couple of the elite car audio engineers in the country.
I'm sorry you find this so difficult to believe.
helotaxi
5,000+ posts
Kilroy was Here
Again, I agree with you if we were able to use the whole car's chassis a a conductive path. We can't. The current MUST flow through the tack welds and the bolts that hold the whole thing together to get to the battery/block/alternator ground. Those are where the resistance comes from, not the sheet metal of the chassis.
dont forget weree not only dealing with tacks and boltd but in many of those places there are overlapping pices of sheetmetal although the welds/bolts are 4 inches apart the metal still makes contact ...trust me ive seam welded a unibody and i put my ground clamp anywhere with no ill effects from non conductivity
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