Ground resistance question..

[volvowith18psi]

While waiting for all my audio stuff to arrive, I did the Big 3 this past weekend in 1/0. I soldered everything using the recommened items in the guide above, and only had sand paper at my disposal to "clean" everything. I sanded the F outta everything I could get my hands on, included the ring terminals, and ground locations.

Now, while bored at work, I was testing the grounds via Ohm meter, with the car off, negative lead to neg. Bat post, and positive lead to all my grounds. The average reading was 1.2ish ohms. The meter itself created a .3 resistance when touching leads together. So, around .8ohms for all the spots I picked. Most were factory spots that I just sanded down really good, or so I thought.

Im reading that anything higher then .2 needs to be re-done... But how can I get it cleaner? Any tips?

is .8 really that bad?

(Everthing thing appeared to be free of paint and dirt)

[Amart88]

[Tarball]

You said all you had was sand paper. Where you able to sand the ground location down to metal? Are you grounded to the frame or body ? Got any pics of your ground locations?

I normally sand down to metal then clean up the area with a chemical that will break grease, grime and oil. You want good metal to metal contact without stuff inbetween.

Also, if you are getting 1.2 at the battery ground location (with 1/0 in place) something is wrong with that run. What resistance do you get on just that piece of ground wire?

[john253a]

if you find that you get pore ground in a few difference place, check the battery grounds, replace and cleane as nessery,

if all else fails run another power wire from battery to amp for ground,

my pic isn't the best but you can see how i did my big 3 with 0/1

it goes from battery (-) to distribution block in 0/1

out of there in 0/1 to block then another 0/1 from same mount on block to alt,

then also out of distribution block i have 3x 4g cables

1 to factory bolt in rails

1 to factory bolt on computer bracket

1 to factory earth on guard (under fuse holder)

then i checked my babyseat bolt holes and they were all under 0.1 so i used them to run to amps

i also didn't use normal solder i used solder for low resistance designed for speaker wires

[dima sochi]

go in USA Im

[JasonJones]

That guys video is a great tutorial but the problem being is the circuit must be active to get a proper reading. Still a good video on demonstrating ground difference potential.

Also DO NOT be mislead by his video in terms of where to place your probes when measuring a circuit. This method is correct if you ground your amps to your batteries. But if you ground your amp to the frame then you would measure from that point to a valid grounding point.

[volvowith18psi]

However I did aquire some of these to try to clean it better next weekend when I have access to a garage again

Ironically, the one connection to that engine bolt thing, which I did the worst sanding on (Bolt int he way) gave the lowest resistance...

That video is actually what inspired me to check mine. The thing that puzzles me is he says to use the "Volts DC" setting and not "Ohms" I tested mine the same way, only on the "ohms" setting....

Add 1 more pic, we all like pics

[john253a]

is the earth on the side panel or firewall

if on side panel look at moving it as a car is painted then assembled so there is paint between the joins of the guard to car,

also if you can run at least 2 grounds but 3 is better

1 to engine (apart of big 3)

1 to body (main body not bolt on panels)

1 to chassis