Amp install - no negative

[Too Late]

Hi all

Going to replace an amplifier and reading through the manual, it doesn't mention a negative connection to the battery



Having never installed an amp, I just wanted to check that it is indeed wired to the ground in the car. Not the negative of the battery

Thanks
Nick.

[300bhp/ton]

Too Late said:

I just wanted to check that it is indeed wired to the ground in the car. Not the negative of the battery

Thanks
Nick.

On modern cars ground/negative of the battery are essentially the same thing. As you have a negative earth, i.e. the main body/structure of the car is directly wired to the negative terminal. Thus all of this is just an extension of the negative terminal.

On some older cars (probably 60+ years old), they where positive earth, in which case the above isn't true.

[SteBrown91]

You don’t wire to the battery you just find something to earth to the chassis (bolt for the seat frame is often the easiest to get to/find and a decent sized bolt for the cables

[ALY77]

The ground terminal on the amp needs to find a nice chunky metal part of the car to make contact with.

Haven't fitted for a long time but my location of choice was always the bolt securing the rear seatbelt clips to the chassis of the car.

[untakenname]

Ideally for best performance you'd want a 4awg cable going back to the battery negative but if you use a multimeter you can probably find a decent ground near to the amp.

[TEKNOPUG]

You want a short a distance as possible from the amp to earth. Seat belt securing bolts are ideal as mentioned. Make sure you clean all the paint off so it's a direct connection to metal. Ideally all equipment should earth at the same location and the earth should be the same (or greater) thickness of cabel (AWG) as the live. Always connect the earth lead first.

[nitrodave]

TEKNOPUG said:

...Always connect the earth lead first.

Surely it makes more sense to connect the earth lead last. If connected first the chassis of the amp is grounded and connecting the positive cable gets risky - if the screwdriver touches the chassis it will short out.

[TEKNOPUG]

nitrodave said:

TEKNOPUG said:

...Always connect the earth lead first.

Surely it makes more sense to connect the earth lead last. If connected first the chassis of the amp is grounded and connecting the positive cable gets risky - if the screwdriver touches the chassis it will short out.

So you're proposing connecting the live to the battery, reconnecting the battery and then whilst holding a 12v "live" wire, attempting to connect that to the amp? Which isn't grounded? I guess you are earthed though...

[anonymous-user]

Ground in the car (chassis earth) is the same thing as the battery negative terminal. Use whichever is more convenient. The thickness (AWG) of your live (+ / positive) cable will dictate how much power you can safely draw, as your chassic ground is thicker than any cable you can fit in a car :-) (well, the thinnest part of the ground path, which will be the thickest wire from the battery negative to the chassis.)