battery Reloc. Wire Gauge Question

[s15specR]

Can anyone tell me if 2 gauge wire will suffice ?

Running it about 12ft from trunk to the engine bay, thanks.

[S-Nation S13]

im pretty sure its a good enough wire thats what im running MAKE SURE YOU INSULATE THA HOTWIRE OR THERE GOES YOUR CAR UP IN SMOKE

[SR_Vlurs]

yea 2g is good enough for that bro

[Maiku240sxS14]

Yes it will do...

[s15specR]

What lenght is you wiore, what did you use to do the relocate, lastly did you getthe wire from autozone or similar ?

Thanks.

[RacerX1]

Napa should carry it, are you running the battery to the starter directly? If so you should use a fuse block between and run 4g between the two.

[Bigsyke]

I wouldnt use the thicker stranded wire for auto use, get the thin stranded stuff that they use in car audio shops.

[g6civcx]

Also keep in mind that whatever you're bolting the wire to, if the wire is too thick it may break off the stud.

For example, starter and alternator bolts are tiny. If you stuck a 0000 wire on these bolts the weight of the wire will probably break the stud.

You want enough but not overkill.

[imverus]

i still don't get this.. if i want to relocate my battery to the trunk due to a fmic, i have to get 2 gauge for the positive and negative? 12 positive from the trunk to the starter and 2 foot negative to a bolt in my trunk? i wanna fit a larger battery cause my small one isn't cutting it at the moment.. someone please explain in further detail, im sorry i need help.

[nismolism]

plz make sure the wire is suitable...u dont want to catch ur car on fire

[nismolism]

u would also want to runn the ground back to the engine or reground all the engine components with like a ground kit...i ran my ground and my 12v back up tothe engine bay

[RacerX1]

Why would you run the ground all the way to the engine bay? Just ground it in the trunk, works just fine for me.

[rb25_s13*CHUKI]

Just ground it In the trunk and buy some 10g or 4g and make your own grounds In the front If your doubting It.

[g6civcx]

Okay, this is getting ridiculous.

The best way to run the positive wire is to use as big a gauge as possible without breaking anything the wire bolts to.

The best way to run the ground wire is to ground each head to a single point on the block, and ground that single point on the block to a chassis ground.

All electronics in the car should be grounded to the single chassis ground.

Use the biggest ground wires that won't shear off anything it's bolted on to.


Any other way will not be as superior as this setup. You want all grounds to a single chassis ground for sensitive electronics to create a single amount of resistance to ground for all electronics.



If you're running stock electronics, run a 2AWG from the battery positive to the stock positive terminal and connect them. Ground the battery in the frame somewhere with an at least 2AWG wire.

Done. It's not that hard.

[Bigsyke]

^^I dont know about that.

Its called common ground, aka your chassis. Doesnt matter where you ground it, as long as the ground cables are as short as possible. If your engine block is grounded, your engine also becomes a common ground along with the chassis. Whats the need for getting the biggest ground wires aside from adding extra weight? I doubt you would need anything bigger than 8ga oxygen free copper.

If you run the ground cable back up because you think you will get a better ground then your a fucking idiot.

[g6civcx]

^^I dont know about that.

Its called common ground, aka your chassis. Doesnt matter where you ground it, as long as the ground cables are as short as possible. If your engine block is grounded, your engine also becomes a common ground along with the chassis.

It's well known that all sensitive electronics should be grounded to a single chassis grounding point.

Like I said, this is the theoretical best to obtain common resistance to ground for all electronics, and may not reflect other considerations.


Whats the need for getting the biggest ground wires aside from adding extra weight?

I agree. Just run all the electronics to the same chassis ground for best performance.

I doubt you would need anything bigger than 8ga oxygen free copper.

I neither agree nor disagree. It depends on the application.

If you run the ground cable back up because you think you will get a better ground then your a fucking idiot.

Nobody here said that, other than the people Russ already scolded.

[Codrifter]

the whole idea around running a bigger cable is to have the least amount of resistance in the wire. just run the biggest cable you can use. thats cause if you run something to small and upgrade the battery like you said your gonna do. if the wires to small and cant handle the current form the battery ur gonna be sweeping your car up with a broom and dust pan. and as far as relocating the ground to the trunk why fuck with something that an engineer thats 5 times smarter than you (no offence intended), designed to work the best for the vehicle and make it performe day in and day out why fuck with it. doesnt make muck sence to me. but hey thats just my 2 cents.

[Bigsyke]

common ground. bat distance short, engine doesn't matter since they're mostly used t prevent electralosis in the water jackets from burning holes.

[g6civcx]

why fuck with something that an engineer thats 5 times smarter than you (no offence intended), designed to work the best for the vehicle and make it performe day in and day out why fuck with it

I'm going to go ahead and disagree with you there.

I typically design better systems than Nissan engineers. The only problem is my systems cost more to build, but in terms of performance, my embedded control systems are superior to most of the OEM stuff you find in production cars because manufacturers have to take other factors into consideration like cost and emissions.

Don't put so much faith in engineers you have never met. Look at the product yourself. Educate yourself so you know what you're looking at.

[g6civcx]

engine doesn't matter since they're mostly used t prevent electralosis in the water jackets from burning holes.

If the engine isn't grounded to the battery's negative terminal, what would a direct current system do with the electron charge carriers?

Why do we use alternating current for houses located far away from the power plant?

[jspeedm]

I'm going to go ahead and disagree with you there.

I typically design better systems than Nissan engineers. The only problem is my systems cost more to build, but in terms of performance, my embedded control systems are superior to most of the OEM stuff you find in production cars because manufacturers have to take other factors into consideration like cost and emissions.

Don't put so much faith in engineers you have never met. Look at the product yourself. Educate yourself so you know what you're looking at.

very well put.

[S-Nation S13]

fyi im selling bout 15 ft of 2 guage wire pm me if your interested

[g6civcx]

This is how most people wire up their cars:

http://img196.imageshack.us/img196/7784/stockwiringm.jpg

They typically neglect to ground the engine back to the frame.

The engine is somewhat insulated from the frame. There is weak conductance between the engine and frame. You may have some through the motor mounts, gearbox mounts, diff mounts, and axles.

When electrons go to the engine via spark plugs and other components, the electrons have no way to return back to the chassis.

After a while, you'll have a slight negative charge in the engine block due to the excess of electrons.

You'll also get a sligh positive charge in the frame due to electron deficiency.

This difference creates an electric potential, ie. voltage, between the block and the frame. At some point, the electrons will spark and jump from the engine block to the frame, kinda like lightning.

I've seen current jump the gap via things like the brake lines, turbo lines, or any other thing that touches the engine to the frame. When this happens, it will fry anything it touches, including braided lines, or even hard lines.

This is how you should ground your car:

http://img156.imageshack.us/img156/6880/goodwiring.jpg

It's pretty self-explanatory. Everything should go to a single grounding point on the chassis.


This is crucial if you're using sensitive aftermarket electronics that operate on a very small range of resistance. For stock electronics it's not so important because the stock stuff is not as sensitive.


Good luck. Ask me if you have any specific questions.

[Bigsyke]

Ok let me ask you;

Why is the engine block grounded at all? let alone in 2 places almost opposite of eachother (IM then the rear of the head), We all know the sensors/harness grounds could be directly extended to the chassis itself. If the engine is grounded to the chassis, why go through the engine. We also know pure water will not conduct, but once a coolant or contaminant is added - galvinized corrosion, electralysis will occur on almost all aluminum or soft metals. Why do we isolate the heatercore, and radiator from the chassis.

ive seen service bullitins say the engine is grounded in 2 opposite places is mainly for a path of least resistance so an underpar electrical system will not energize the aliminum. However if the chassis becomes energized the current can flow back to the engine block.

My understanding is by grounding only 1 engine ground to the same spot as the bat - on the chassis, in the event of the chassis becoming energized from an underpar electrical system, the current can skip the chassis and directly access your engine block. Every aluminum engine ive seen has spaced out the -bat ground from all the other grounds, because the chassis is like an insulator, the engine is also like an insulator thus the sensative sensor grounds ended up being on the engine not the chassis. People have ran that circle of earth grounding systems and had a hole eat right through the water pump, radiator and heater core. There is just too many factors you have to dynamicaly acount for, like having an MSD system.

Thats just what ive heard/read, ive never seen anything like that, but ive been toying with these stupid grounding systems from years on 5 different cars, I also picked up about 300ft of 2-4ga wire when Circuit city went under. I just upgraded the OE wiring and found that OE isnt "damaging" anything. But your diagram does seem interesting. Why do you have only 1 ground going to the chassis? doesnt this leave room for energy to pass through half the engine?

[g6civcx]

I apologise if this is getting into a different area than the original question. If you feel that this needs to be pruned and broken down into a different thread, then please do so.

Before we get into a big debate, please read this statement carefully:

Stock electronics are NOT as sensitive as aftermarket electronics. The accepable range of resistance to ground for stock electronics is much, much broader than the tolerances for sensitive electronics.

If you accept the statement above as being generally true, then grounding with stock electronics is not as crucial as grounding for aftermarket electronics.

So if you're just running stock electronics with a few gauges here and there, grounding is not as crucial. You can follow the factory grounding scheme and you will generally be okay.

If you're running extremely sensitive sensors and electronics that operate on a very narrow range of resistance, grounding becomes more crucial.

Why is the engine block grounded at all? let alone in 2 places almost opposite of eachother (IM then the rear of the head), We all know the sensors/harness grounds could be directly extended to the chassis itself. If the engine is grounded to the chassis, why go through the engine. We also know pure water will not conduct, but once a coolant or contaminant is added - galvinized corrosion, electralysis will occur on almost all aluminum or soft metals. Why do we isolate the heatercore, and radiator from the chassis.

I do not understand your question. Generally the engine has weak electrical connectivity to the frame. If we insulated the engine completely from the frame, we will build up excess electrons in the engine as I discussed above.

ive seen service bullitins say the engine is grounded in 2 opposite places is mainly for a path of least resistance so an underpar electrical system will not energize the aliminum. However if the chassis becomes energized the current can flow back to the engine block.

This factory grounding scheme is done mostly for convenience and cost control, and for reasons above (namely stock electronics are not sensitive).

My understanding is by grounding only 1 engine ground to the same spot as the bat - on the chassis, in the event of the chassis becoming energized from an underpar electrical system, the current can skip the chassis and directly access your engine block. Every aluminum engine ive seen has spaced out the -bat ground from all the other grounds, because the chassis is like an insulator, the engine is also like an insulator thus the sensative sensor grounds ended up being on the engine not the chassis. People have ran that circle of earth grounding systems and had a hole eat right through the water pump, radiator and heater core. There is just too many factors you have to dynamicaly acount for, like having an MSD system.

I also don't understand your comments.

Thats just what ive heard/read, ive never seen anything like that, but ive been toying with these stupid grounding systems from years on 5 different cars, I also picked up about 300ft of 2-4ga wire when Circuit city went under. I just upgraded the OE wiring and found that OE isnt "damaging" anything. But your diagram does seem interesting.

The OE wiring is done mostly for convenience and cost, as discussed above. To be honest, I don't place much stock in OE Nissan wiring.

As discussed above, I have just as much electronics design experience as a typical Nissan engineer. The advantage is that I'm not limited by assembly line efficiency, cost, and bureaucracy.

Why do you have only 1 ground going to the chassis? doesnt this leave room for energy to pass through half the engine?

The diagram above assumes that all engine accessories that see current are properly grounded to the head and/or block.

Of course, if you have any insulated component that sees current, you need to ground that component to the block or the chassis ground.

The concept is to reduce what's called a "ground loop". This is when 2 different components see different amounts of resistance to ground.

In this situation, the current can recirculate between the 2 components and cause unpredictable behaviours.

You want a single grounding point for all the electronics so that all components see a fixed amount of resistance to ground.

There will always be small variations based on the ground wire length, but you try to reduce these variations as much as possible.

Variances on the scale of 10 or less Ohms may be acceptable for all electronics. 10-1000 Ohms may be okay for stock stuff, but may not be okay for aftermarket stuff.

1000+ Ohms of variances may not be acceptable for even stock stuff.


If I can plot a 3D graph of electrical conductance on the unibody frame, you can see the variations. The frame is not a ubiquitous piece as we all assume. Some spots are more conductive, while other spots are not (e.g. spot welds, insulation, glue/tar, etc.).

To eliminate these variations, you choose a single point on the chassis to ground the entire system to minimize these variations.


Current will follow the path of resistance. So even though the engine may be grounded, albeit weakly, to the frame, when you connect a single ground wire from the block to the frame, you hope that all current flow will be via the ground wire because the ground wire has less resistance than any other path.

[redpotatoes]

Gauge 0 with 150amp fuse. That's how I did mine.