How do you test where attaching your ground to your vehicle is good enough?

[dyabolical 10+ year member]

" The ideal ground is runnign a second length of wire all the way to the battery like your power. "

With this, i must disagree.

 

[Ruffy 10+ year member]

gotta love how many contradictory statements are made on grounding.

 

[briman1001 10+ year member]

Then you are not surprised why I was having issues. I do not get the picture of the jack. It is just screwed down to the vehicle by way of a mount. Does not seem like a fool proof way to ground a lot of current to me. What if you have to remove the jack. What if the connection between the jack holder and vehicle body is over painted surfaces? It must work for you though. eh?

 

[theCybe 5,000+ posts]

The jack picture is an ongoing joke from www.ghettoinstalls.com //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

Pay no mind.

 

[Flipx99 5,000+ posts]

The jack picture is an ongoing joke from www.ghettoinstalls.com //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif
Pay no mind.

x2. Sorry to confuse.

Seriously, what I do in a trunk car is find the bracket where the trunk tensioning bars are. Drill a hole, sand to a shiney metal finish and use that.

Good luck

 

[Rattlebrain 10+ year member]

Sorry to confuse. Just posting a pic of the "jack"ed up ground.

Get DVM (digital volt meter) and connect the neg lead to the neg on your battery. Then set the meter to ohms and put it where you can read it and use the positive lead to probe possible grounding locations. The location with the least resistance is your best bet.

 

[ngsm13 5,000+ posts]

Scrape paint to bare metal, check underneath to make sure no obstructions, take self-tapping screw and drill your own ground.

nG

 

[briman1001 10+ year member]

Sorry to confuse. Just posting a pic of the "jack"ed up ground. Get DVM (digital volt meter) and connect the neg lead to the neg on your battery. Then set the meter to ohms and put it where you can read it and use the positive lead to probe possible grounding locations. The location with the least resistance is your best bet.

Ok I can do this. Was looking for a reason to buy a DMM anyway. I am guessing you need 2 long wires from the battery to the DMM because I am securing the ground in my trunk.

 

[aaron7114 10+ year member]

Sorry to confuse. Just posting a pic of the "jack"ed up ground. Get DVM (digital volt meter) and connect the neg lead to the neg on your battery. Then set the meter to ohms and put it where you can read it and use the positive lead to probe possible grounding locations. The location with the least resistance is your best bet.

How would you go about doing this if you are grounding the amp in the trunk? DMM cables aren't that long lol.

 

[Rattlebrain 10+ year member]

You just need to get some wire and extend your leads. Don't cut your leads, just wrap them, clip them, what ever. Also remember that when you extend the leads, you may increase resistance in the leads themselves. With your meter set to ohms, touch your positive and neg extended leads together and see if it shows resistance. Hopefully it wont but if it does, make sure to take that into account when finding your ground. Its really not that hard to do. It will probably take you longer to find extra wire. lol Also make sure that you are not touching the bare wire of the leads to any metal or you will get a false reading. I hope this makes sense. Like I said, its not hard.

Lots of people may say its unnecessary to do this but if you want to make sure that you have a good ground, it sure doesn't hurt and it only takes a minute to do.

Good luck.

 

[helotaxi 5,000+ posts]

Ideally your ground resistance should be low enough that taking a direct reading of the resistance is going to be beyond the capability of your average DMM. The definition of "ground' is a point of zero potential. With the car off, the closest you will get to this is the negative post of the battery. With the car on, the case of the alt is your true ground. Since the connection between the alt and the negative battery post should have been upgraded, you can just about count those two as the same. From the negative battery post, anything you add betwen the amp and that point is going to add resistance. You can mess around with your ground in the trunk and gamble with the true unknown of the resistance of the car's structure. Since 90%+ of the cars on the road don't have a frame anymore, your conducting path is goint to have to go through a bunch of tack welds, glued seams and bolted panels to get to the battery. the other route is to run a piece of wire the same size as your power cable directly back to the battery. You now have a known value for ground. If your power wire is properly sized, then you also know that your ground is sufficient. Of course with a system using only 4ga or smaller power cable, the chassis will work just fine 99% of the time, but once you get bigger than that, you can either guess that it will be OK or know that it will.