Truth?

[mil81 10+ year member]

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.

That would be cool. I'd like to hear what they have to say.

 

[PaulD 10+ year member]

The reason SQ guys like myself use the chassis as a ground is that running a seperate wire to the battery for ground just gives the ground for the amps a different resistance to ground and may cause a ground loop. This will give you an alternator whine that will be very difficult to get rid of.

If you are running a LOT of power for SPL, you may find it necessary to run a bunch of runs of large wire to the battey for ground.

 

[mil81 10+ year member]

Awesome Paul. Thanks. That's what I was thinking. I have always been taught to keep the ground wire as short as possible to eliminate any noise issues.

So to sum it up, if you have running huge power, it would be a good idea to run a ground wire to the battery. If you're going to sound quality, it is a good idea to use a chassis ground, with the shortest possible run, of the biggest wire you can.

 

[ultimate157 5,000+ posts]

The reason SQ guys like myself use the chassis as a ground is that running a seperate wire to the battery for ground just gives the ground for the amps a different resistance to ground and may cause a ground loop. This will give you an alternator whine that will be very difficult to get rid of.
If you are running a LOT of power for SPL, you may find it necessary to run a bunch of runs of large wire to the battey for ground.

Not really...

 

[mokedaddy 5,000+ posts]

The reason SQ guys like myself use the chassis as a ground is that running a seperate wire to the battery for ground just gives the ground for the amps a different resistance to ground and may cause a ground loop. This will give you an alternator whine that will be very difficult to get rid of.

This is not true. Ever wonder why when you check for ground loops you use the negative terminal of the battery? Heres a hint: The battery is the reference ground. Use large enough wire and you will have zero problems.

 

[PaulD 10+ year member]

Not really...

I love your insightful rebuttals .....

The question was about SQ systems ... I have yet to see one with more than one 1/0 power wire.

And mokedaddy, when was the last time you had engine noise with the engine off. The battery is NOT the source of power for the vehicle when the engine is turned on. Honestly though, I have not had engine whine problems since like the early 90's (turned out to be a crappy component), so I don't have to check for ground loops. There are ways to find if spots are going to be noisy ground spots or RCA paths. Since you guys seem to be such experts, perhaps you could enlighten the CA.com community on how to detect or avoid grounds loops and alternator whine (without running 8-10 runs of 1/0 Ga wire to the neg batt post), which is way out of the cost and complexity range the average guy is willing to do.

 

[ultimate157 5,000+ posts]

I love your insightful rebuttals .....
The question was about SQ systems ... I have yet to see one with more than one 1/0 power wire.

//content.invisioncic.com/y282845/emoticons/fyi.gif.9f1f679348da7204ce960cfc74bca8e0.gif I have one + and one - 1/0 run to the battery, and have absolutely no noise in my system. Running active and 2 mag 15's sounds crazy good.

And before you go saying "2kw and 2 15's isn't SQ... The gain is barely up on the sub amp.

 

[Rashaddd 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.....

Right, but we have to run a pipe from the end of the creek to the spring.

However, I'd have to agree that grounding to the battery will be better.

Go ahead and test the resistance yourself if you think otherwise, a dedicated run of wire will be better than making 10 more transitions through pieces of metal, just to get to another dedicated run going to the battery...

 

[PaulD 10+ year member]

I would not waste my time running a single 1/0 gnd wire, but to each his own.

To measure differences in resistance like that to find ground loops, you will need a multimeter capable of reading mOhms. Most are nowhere near that accurate. I have an older car, so I don't think the resistance accross the body is that big of a deal. Maybe newer cars are a little worse.

 

[mokedaddy 5,000+ posts]

I love your insightful rebuttals .....
The question was about SQ systems ... I have yet to see one with more than one 1/0 power wire.

And mokedaddy, when was the last time you had engine noise with the engine off. The battery is NOT the source of power for the vehicle when the engine is turned on. Honestly though, I have not had engine whine problems since like the early 90's (turned out to be a crappy component), so I don't have to check for ground loops. There are ways to find if spots are going to be noisy ground spots or RCA paths. Since you guys seem to be such experts, perhaps you could enlighten the CA.com community on how to detect or avoid grounds loops and alternator whine (without running 8-10 runs of 1/0 Ga wire to the neg batt post), which is way out of the cost and complexity range the average guy is willing to do.

Yes it is. About the only thing run directly off the alternator is headlights.

And I have never had noise issues either so again your point is moot.

 

[mokedaddy 5,000+ posts]

I would not waste my time running a single 1/0 gnd wire, but to each his own.
To measure differences in resistance like that to find ground loops, you will need a multimeter capable of reading mOhms. Most are nowhere near that accurate. I have an older car, so I don't think the resistance accross the body is that big of a deal. Maybe newer cars are a little worse.

They are.

 

[tommyk90 5,000+ posts]

Yes it is. About the only thing run directly off the alternator is headlights.
And I have never had noise issues either so again your point is moot.

Err?

Everything runs off the alternator when the car is running. The batteries main purpose is to start the vehicle and to help with any high draw demands. The alternator supplies all the current that the car is demanding.

Nothing runs directly off the alternator. The power wire from the alt goes to the fuseblock where it is then distributed out to the rest of the car. Remember when the mythbusters did that test with the bullet for a fuse for the HEADLIGHTS? They replaced the headlight fuse with a bullet. How could they do that if the headlights run directly off the alternator?

 

[yischrax 10+ year member]

I agree with the last statement with 1 thing to add the MAIN reason for a battery when the vehicle is running is to filter out any a/c current left from what your rectifiers in your alternator aren't able to. Other than that I agree. Seems to me there is no best ground there is a best ground for each and every car and there is no way to know what will work best unless you try it. What is the worst case if you don't find the 0 gauge ground to work use it as a second power wire and drop resistance that much on the + side. That or when you hook into your ground block in the back mount your block to the chassis and to your 0 gauge going up front. In this case all your doing is dropping resistance to the rear of the care threw the wire or isolating the ground loop in the posibility of having one. Seems to me this one would be more of a trial and error if you have the cash for some extra 0 gauge or if you have some laying around. To me seems as though the smart man would think if I have a ground loop with the 0 gauge run and it turns out the 0 gauge has less resistance would be to double the size of my ground from my only component that is not going to be hooked up to what is in the rear of the vehicle (deck) and hook that directly to the battery in the front to lower the resistance in that wire to the same amount that is in the wire going to the back

 

[ultimate157 5,000+ posts]

The REAL answer is that you have TWO sources of power while the car is running, and one while it is off.

When the car is off, the source is the battery. Plain and simple. Negative on one side, + on the other. - is the source, + is the return.

When the car is running, you have the alternator providing power as the PRIMARY source, and the battery is your SECONDARY source. A lot of newer vehicles have the alternator run through the fuse box where it is distributed to the electronics, but a lot of older cars have it run straight to the battery. This makes the posts a distribution point for ALL POWER. When the load demand exceeds the supply of the alternator (Current maxed on the alt, voltage begins to fall below the battery's resting voltage, therefore creating a potential), the battery is brought into the equation as a source and the load is shared.

 

[Ferendon 10+ year member]

I love your insightful rebuttals .....
The question was about SQ systems ... I have yet to see one with more than one 1/0 power wire.

And mokedaddy, when was the last time you had engine noise with the engine off. The battery is NOT the source of power for the vehicle when the engine is turned on. Honestly though, I have not had engine whine problems since like the early 90's (turned out to be a crappy component), so I don't have to check for ground loops. There are ways to find if spots are going to be noisy ground spots or RCA paths. Since you guys seem to be such experts, perhaps you could enlighten the CA.com community on how to detect or avoid grounds loops and alternator whine (without running 8-10 runs of 1/0 Ga wire to the neg batt post), which is way out of the cost and complexity range the average guy is willing to do.

Jesus fvck, I hope you're kidding.

The battery and alternator share the job of supplying power to a running engine. Typically, the 3 meet at the (+) battery terminal, where the alternator and battery become a single power source, from which the fuse block draws power. In order for the two to work in a particular order, the battery-to-fusebox connection would have to be switched.