Chassis amp grounding vs. running ground back to battery

[dwc 10+ year member]

Can I get some advice on this? This is my rookie install and I have read some that say you ground the amps to chassis close to the amp, and then I read about others who run a ground wire all the way back to the battery. What about doing both via a distro block?

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[ravens9322 10+ year member]

hmmm I never thought about that... I'm a body ground kinda guy

 

[pr-festiva 10+ year member]

It depends on your car and what you plan on running,,,you wouldnt need both

 

[IgnoreMe 5,000+ posts]

it depends on how much you know about your car and how much you want to spend.

1) do NOT let anyone tell you that if your ground wire is over 3ft long, its a bad ground. by grounding to the chassis, you have just inadvertently grounded to the battery as well. the chassis acts like a wire and it all leads back to the battery whether you like it or not. and last time i checked, i dont know of any cars that have a chassis that is under 3ft long...

2) IF you know that you have a nice chassis ground that has minimal resistance and will not cause a voltage drop, use it.

3) if you dont know or trust your car, use a dedicated negative run

 

[blackbonnie 5,000+ posts]

i personally will not go back to body grounding no matter what vehicle. i learned a while ago that its not always the best. i ground straight to the battery, the length of you wire run (we will say 18 feet) has less resistance then the metal in which the ground will travel through the body. now is this true, some case yes, some no, but at least when you ground to the battery you know your getting a good ground and can elimanate that from any problems or future problems you may have.

 

[dwc 10+ year member]

The argument I read against battery grounding [car audio book] is based on the battery being a "noisy" place to ground.

 

[GMCJimmyslt2000 10+ year member]

i say if ur worried bout voltage drops...go to the batt.

but for dd, just ground to frame

 

[bikinpunk 10+ year member]

I've never had an issue with grounding to the frame.

Just get a DMM. If you have low resistance there, then there's no reason to ground to the battery since you're essentially doing so by grounding the the frame.

 

[IgnoreMe 5,000+ posts]

The argument I read against battery grounding [car audio book] is based on the battery being a "noisy" place to ground.

thats fine...but like i said once you ground to the chassis...the chassis is in itself, a wire. the battery is grounded to the chassis underneath the hood, there is really nothing you can do about it unless you want to completely remove the battery from your car and go flintstones style on driving places //content.invisioncic.com/y282845/emoticons/fyi.gif.9f1f679348da7204ce960cfc74bca8e0.gif. go take a look

 

[IgnoreMe 5,000+ posts]

I've never had an issue with grounding to the frame.
Just get a DMM. If you have low resistance there, then there's no reason to ground to the battery since you're essentially doing so by grounding the the frame.

you need to run a wire all the way up to the battery ground wire (disconnect the ground wire and connect your new wire at the terminal on the end of it) and attached the other end to one of your leads. then use the other lead and probe the spot where your potential grounding point is (unless you got 12+ft dmm probes, you will need to make a probe extension cord, if you will)

i hope you dont just stick both leads on your grounding point and call it a day when it reads 0...

 

[bikinpunk 10+ year member]

you need to run a wire all the way up to the battery ground wire (disconnect the ground wire and test at the terminal on it) and attached it to one of your leads. then use the other lead and probe the spot where your potential grounding point is (unless you got 12+ft dmm probes...)
i hope you dont just stick both leads on your grounding point and call it a day...

You'll need some extra length of wire to reach from where your ground is to the battery.

Now, take one lead of the multimeter (doesn't matter which one) and touch it to the ground location. Take the other lead, use some sort of wire or extended leads, and attach it to the negative battery post. Let us know what reading you get. You should be getting below .5ohms. That's a good starting point. Depending on your wire, you might have some resistivity in there.

Also, make sure you touch the two leads of the multimeter together before testing so that you can see what the resistivity of the DMM itself is. For example, touch them together and you may get .1 ohms. Then, whatever your ground spot reads, take .1 ohms off of it.

//content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

 

[IgnoreMe 5,000+ posts]

//content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

lol, gotta clarify for the newbies //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

they will stick both leads on the chassis 2 inches apart, or hell, even on the same bolt, and say "good ground!"

 

[Pyro_By_Nature 5,000+ posts]

I used to just ground to the body, but now I run the ground wire from the batt.

 

[bikinpunk 10+ year member]

Actually, what I do is use my DMM as the ground.

Strange thing is that the radio never powers on. //content.invisioncic.com/y282845/emoticons/mad.gif.c18f003ab0ef8a0d9c27ca78d77a6392.gif

//content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

 

[bikinpunk 10+ year member]

I think the real question to those who go to the battery is why? Are you having trouble grounding to the frame/body? Inducing noise?

I'm just trying to understand why people go this route.