Adding ground wire between batt and chassis

[eRiCdWoNg]

I've done this on all my previous cars. They were Japanese so they used the top mount for OEM. So I would get a side mount terminal and add more ground wire from the batt to the chaassis. So, now I did it again, this time in reverse cause I have a GM car. I bought a 1 gauge 31 inch cable and mounted it to my Exide Orbital XD's top and grounded it to the OEM ground point. It looks pretty factory except for the part that actually goes onto the battery. I think it may have made a difference in the performance of my largest amp. I notice that the headlights do not dim as much even when I have the system cranked. Is this smoking crack and in my mind or is there something actually going on?

[Immo_G]

It does actually make a difference, the ground wire is usually pretty pathetic on most cars. Definetly recommended to replace once you get a serious amp.

The entire amp current is going through that cable as well as headlights, so if its high resistance, it'll cause a voltage drop, dimming headlights and costing amp power.

[edpgc]

When the cars running all of the power should be coming from the alternator, which is of course connected to the car body. However for instantaneous loads such as bass beats which the altenator can't react too quickly enough, then the battery will provide the difference.

Hence by improving this link you have reduced the lights dimming.

[maylar]

Originally posted by edpgc
When the cars running all of the power should be coming from the alternator, which is of course connected to the car body.

Alternator is grounded to the engine. From there it goes to battery negative and from there to the car body through the wire he just replaced. The only other attachments from alternator to body are the braided wires intended for signal grounds for sensors and such.

[edpgc]

Still all the power should be coming from the altenator, and not passing the battery. On every car I have seen the engin is grounded to the car body, not the battery. Why would it, the car body is a far more effective ground plane, than a point connection to the battery.

[maylar]

The engine is grounded to the body, but through relatively small wires. Engine and tranny mounts to the frame are rubber isolated and not reliable electrical paths. In a car with full frame, the body is also rubber isolated.

The main alternator return is the wire from the block to the battery (which also handles starter current), and from the battery negative to body. Those 2 and the alt to battery wire are the "magic 3" that people recommend replacing.