quick grounding Q

[Brit rider 10+ year member]

Ok firstly, i just want to say i nearly finished reading BCAE1.com and WOW, if any of you haven't already used this resource do, best thing i ever read.

there is however one thing i don't understand.

Is this statement correct?

when an amp is connected up you have two power wires. a ground and a positive. the electrons flow into the amp through the ground wire?

this confused me as this means that the power is actually coming from your chassis? i.e battery is connected to that and your ground for the amp is connected to the chassis.....

what i was thinking was, theoretically shouldn't you get better performance (via lower resistance) if you simply hooked a wire from the neg post of your battery straight to the ground terminal on your amp?

or am i wrong/confused.

or do people do this anyway?

sorry if this is a dumb question... i truly am a newbie at this //content.invisioncic.com/y282845/emoticons/rolleyes.gif.c1fef805e9d1464d377451cd5bc18bfb.gif

Cheers,

Brit.

Click to read more...

 

[JimJ 5,000+ posts]

what i was thinking was, theoretically shouldn't you get better performance (via lower resistance) if you simply hooked a wire from the neg post of your battery straight to the ground terminal on your amp?

If you have a good chassis ground connection, this shouldn't mattter - unless you have a major conducted noise problem.

 

[Brit rider 10+ year member]

thanks jack, again you alsways seem to be the first to answer my questions, cheers.

so does the power come directly through the chassis?

 

[JimJ 5,000+ posts]

If I remember my basic electronics, yes //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif - current flows from the negative terminal on the battery (and thusly, the negative chassis ground) to the positive terminal. Which is why you always disconnect the positive lead first if you're working on the system to prevent you from becoming what completes the ground return.

 

[req 5,000+ posts]

to awnser the question quite bluntly,

the chassis actually becomes the 'wire' that connects the amplifier's 'grounding location' to the batteries 'grounding location' - this is why we have really fat wires here. all wire is is metal strands. all a chassis is a metal frame. and since all elements that are metal conduct electricity, the chassis is a perfect way to save yourself some wire - because every single electronic component is grounded so that two wires do not need to be ran from where that electronic this is, all the way to the fuse box, then the battery //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

if you wanted to, you could run it directly to the - post. and sometimes, if the distance is shorter- and\or its eaiser, thats a graet way to do it - because you can calculate your resistance. but in most everyones installation, its just no practical to run two 1\0 guage wires from your engine to your trunk, if you get my drift //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

hopefully i helped a little //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

and that website is awesome.

 

[maylar 10+ year member]

If I remember my basic electronics, yes //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif - current flows from the negative terminal on the battery (and thusly, the negative chassis ground) to the positive terminal.

Yep. Current is Electron flow... negative to positive.

Which is why you always disconnect the positive lead first if you're working on the system to prevent you from becoming what completes the ground return.

NO, NEVER! You don't want a wrench comming between the battery terminal and ground (bzzzt).. so ALWAYS disconnect the ground first.

 

[ANeonRider 10+ year member]

Also... always connect the ground first when wiring anything.

 

[B@SSAN8OR 10+ year member]

if you are running 1/0 awg wire you always want to run a ground from the battery cause the resistance of 1/0 will be alot lower then you battery chassis. there is a reason why they make big wire. to have more current flow. most vehicle chassis have a resistance close to 4 awg wire. or more depending on the vehicle. it is more of a pain in the *** to run 2 wires especially 1/0 awg. but it will help you in the long run. i install 1/0 wire all the time. My shop is almost the only one in the sacramento area that actually does on a normal basis.

 

[squeak9798 5,000+ posts]

most vehicle chassis have a resistance close to 4 awg wire.

I've also seen tests that claim a typical vehicle's chassis has a resistance equal to 2/0ga wire.

 

[forbidden 10+ year member]

For even a little more insight, have a look in the car audio forum of http://www.the12volt.com and read the grounding stickies at the top. It might just add a little more info to this question.

 

[johnecon2001 5,000+ posts]

Also... always connect the ground first when wiring anything.

for some reason I thought that was the second thing to be connected on an amplifier (power first), due to if your screwing the power wire down and the screwdriver touches the chassis of the amp, it shorts it. But if you ground after the power wire is in, you no longer run that risk.

Correct me if I'm wrong.

 

[ANeonRider 10+ year member]

Shouldn't be an issue if you don't have the fuse in the power wire... NEVER EVER EVER should you be hooking up a live wire. Always pull the fuse first.

 

[Brit rider 10+ year member]

ahhhh.. it all makes perfect sense! haha.

Nealry done on BCAE1.com now, wow it covers pretty much everything, this audio stuff is so interesting and that site is giving me the confidence and know-how to install my own system... just hope i do it right!! haha