front to rear neg. wire runs ????'s

[nkrell11 10+ year member]

One thing I noticed when I ran a negative run is that it reduced my voltage drop compared to just a regular chassis ground, not saying this would always be the case but for me it made a difference.

 

[tommyk90 5,000+ posts]

so equal amount of runs from front to rear it is.

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One thing I noticed when I ran a negative run is that it reduced my voltage drop compared to just a regular chassis ground, not saying this would always be the case but for me it made a difference.

It can make a difference for a lot of people depending on how much power they are running and how much current capability they have under the hood.

 

[nkrell11 10+ year member]

@tommyk90 love the avatar man.

 

[splwj47 10+ year member]

//content.invisioncic.com/y282845/emoticons/thumbsupwink.gif.129404938effda6ad9cca39e7f4b58a3.gif


It can make a difference for a lot of people depending on how much power they are running and how much current capability they have under the hood.

im gonna need more wire now. //content.invisioncic.com/y282845/emoticons/fro.gif.c695f1f814b01c4ad99fe7f8cccadd29.gif

 

[dumpbeast86 10+ year member]

Sorry, but this is incorrect. Copper will ALWAYS be a better conductor than steel, given a certain thickness. Most vehicles are made up of thin sheet metal, welds, and unibody construction. The only vehicles that can support decent current draw (200-300 amps) are FULL FRAME vehicles where the owner has also upgraded all the big 3 wiring under the hood as well.
Steel is a very VERY poor conductor of electricity. I believe copper is about 10x more conductive than steel, if not more. Factor in that most steel used in vehicles is not great quality AND is full of spot welds and you reduce that conductivity even further.

Keeping grounds short is an old myth. In actuality, by keeping your ground wire short and connecting it to the chassis or vehicle body, you are increasing resistance than if you had a direct copper connection to the front battery/alternator (where that ground originates from). No matter where you ground to in the rear, the electrical current still has to flow all the way up to the source. Electricity is a two-way street.

The reason that most people don't do it is because of the cost of additional wire and most often it doesn't benefit them over a sufficient chassis ground.

i made no effort to advertise steel as a better conductor, we all know copper is. i simply pointed out that with a known good ground i.e., the steel frame, more resistance to ground can/will build up over 15 feet of wire as opposed to less. a solid ground has no resistance to ground. any resistance comes in through the material you use to tie grounds together. if you don't believe me, use your dmm and test resistance on a known good ground. how many grounding straps to a battery you have seen in any application, car, tractor, boat, plane, whatever, that were over 1-2 feet long? and yes i have a solid full frame, and you are correct, unibodies are more difficult to find a good ground.

 

[husker77 10+ year member]

I'm not sure testing with a dmm is that great of a method for testing a ground. Take a run of large wire, say 1/0 and test it, now take 1 strand of the same length of wire, it will show the same resistance if it is the same quality of wire, but obviously they will not have the same current carrying capacity. I understand that isn't exactly what we are talking about here, but I just want people(mostly noobs) who are reading this to understand a dmm resistance reading isn't the end all be all measurement of a systems capacity.

 

[dumpbeast86 10+ year member]

I'm not sure testing with a dmm is that great of a method for testing a ground. Take a run of large wire, say 1/0 and test it, now take 1 strand of the same length of wire, it will show the same resistance if it is the same quality of wire, but obviously they will not have the same current carrying capacity. I understand that isn't exactly what we are talking about here, but I just want people(mostly noobs) who are reading this to understand a dmm resistance reading isn't the end all be all measurement of a systems capacity.

i agree, but yeah that doesn't apply to what we are talking about. a continuity test would also work just the same on your dmm, in regards to testing grounds

 

[Wanacustomx 10+ year member]

Sorry to jump in on the convo... The biggest alt I can get for my car is a mechman 270 or singer has the 300 amp for mine. I'm gonna be running around 8k total in my exploder this question was just on my mind.. How many runs should I do positive and negative? I was thinking two... I will have a xs d6500 under the hood and 3 xp3000's for the bank... I've already got 100ft of knu kolossus fleks so to do 2 or more runs I'll need at least another hundred foot, which will probably get me 3 runs of pos and negative...

 

[gckless 5,000+ posts]

Sorry to jump in on the convo... The biggest alt I can get for my car is a mechman 270 or singer has the 300 amp for mine. I'm gonna be running around 8k total in my exploder this question was just on my mind.. How many runs should I do positive and negative? I was thinking two... I will have a xs d6500 under the hood and 3 xp3000's for the bank... I've already got 100ft of knu kolossus fleks so to do 2 or more runs I'll need at least another hundred foot, which will probably get me 3 runs of pos and negative...

You should start a new thread. We'll be able to help you better.

 

[Wanacustomx 10+ year member]

Thanks I'll do that

 

[mlstrass 5,000+ posts]

[quote name='jockhater2']nope.
ask @mylows10 ; if you got a problem with it.
That is just what he told me to do.[/QUOTE]

Not trying to put you on the spot, just don't believe everything you hear/read on car audio sites.

 

[mlstrass 5,000+ posts]

Well I can tell you that when I upgraded my wires and ran 6 grounds frt to back and 8 powers frt to back. Then 2 short grounds off my disto block on my 2 powerbass xta 5000's I went from a 150.7 to a 152.8 no sweat and I could burp that in the lanes all day. It helps with current flow between the frt and rear batteries and helps charg the rear batteries faster. That's just what and how it worked for me helped me beat my closest rievel on the west coast. Who has only been beaten in competition in the lanes once in 7 years out here ( by me )

You had other issues if you gained that much on a burp, especially with a batt bank in the rear.

My last car had 1 run of 1/0 POS to the back and 12 batts in the rear. I went to 4 runs of 1/0 and gained .1v at the rear and zero on the meter.

 

[tommyk90 5,000+ posts]

i made no effort to advertise steel as a better conductor, we all know copper is. i simply pointed out that with a known good ground i.e., the steel frame, more resistance to ground can/will build up over 15 feet of wire as opposed to less. a solid ground has no resistance to ground. any resistance comes in through the material you use to tie grounds together. if you don't believe me, use your dmm and test resistance on a known good ground. how many grounding straps to a battery you have seen in any application, car, tractor, boat, plane, whatever, that were over 1-2 feet long? and yes i have a solid full frame, and you are correct, unibodies are more difficult to find a good ground.

A continuity test with a DMM isn't going to prove that a frame is better than a run of 1/0. You need a load on the ground to see the benefits.

As I've stated, the only time someone will benefit with direct 1/0 runs to the alt and front batteries is:

1) they have a lot of current capability up front

2) they have a large enough system to fully utilize the current capability up front

3) all of their underhood wiring has been upgraded. Engine grounds, chassis grounds, etc.

Comparing a high-powered stereo system to a tractor is a completely irrelevant point. Manufacturers build vehicles with stock intentions in mind, not 10,000 watt stereos. Have you ever dealt with a multiple alternator system? Trying to pass 1000+ amps through a frame rail is not only dangerous, it's potentially damaging to your equipment.

A chassis ground is only as good as the material you are passing electrical current through as well as the SOURCE of the ground, i.e. the front battery and alternator. Where do you think your rear chassis ground comes from? It's isn't magical, it comes from the front battery and alternator. The current has to travel the same distance to the front whether it's through the chassis or through a piece of 1/0. This is why if you ARE using chassis grounds that it's important to upgrade all the wiring under the hood as well so you are relying on the chassis for the shortest distance possible.

Not trying to get into an argument here, but the bottom line is that a GOOD chassis ground AND upgraded big 3 is sufficient for most normal setups (1 alt, 1 batt under the hood, "normal" wattage levels). When you get past "normal" is when better conductivity is needed. There's no such thing as overkill when it comes to electrical. Hell, I run chassis grounds AND direct runs.

 

[dumpbeast86 10+ year member]

A continuity test with a DMM isn't going to prove that a frame is better than a run of 1/0. You need a load on the ground to see the benefits.
As I've stated, the only time someone will benefit with direct 1/0 runs to the alt and front batteries is:

1) they have a lot of current capability up front

2) they have a large enough system to fully utilize the current capability up front

3) all of their underhood wiring has been upgraded. Engine grounds, chassis grounds, etc.

Comparing a high-powered stereo system to a tractor is a completely irrelevant point. Manufacturers build vehicles with stock intentions in mind, not 10,000 watt stereos. Have you ever dealt with a multiple alternator system? Trying to pass 1000+ amps through a frame rail is not only dangerous, it's potentially damaging to your equipment.

A chassis ground is only as good as the material you are passing electrical current through as well as the SOURCE of the ground, i.e. the front battery and alternator. Where do you think your rear chassis ground comes from? It's isn't magical, it comes from the front battery and alternator. The current has to travel the same distance to the front whether it's through the chassis or through a piece of 1/0. This is why if you ARE using chassis grounds that it's important to upgrade all the wiring under the hood as well so you are relying on the chassis for the shortest distance possible.

Not trying to get into an argument here, but the bottom line is that a GOOD chassis ground AND upgraded big 3 is sufficient for most normal setups (1 alt, 1 batt under the hood, "normal" wattage levels). When you get past "normal" is when better conductivity is needed. There's no such thing as overkill when it comes to electrical. Hell, I run chassis grounds AND direct runs.

I am not sure how to "load a ground". you were right earlier when you said electricity is a two way street, but i am not sure you fully understand why that is.

I am a mechanic, I have dealt with multiple alternator setups on tractors and heavy equipment. It is completely relevant for that reason, these machines are drawing 600+ amps on 12-24 volt systems. They dont have wiring runs from front to back and batteries all over. simply huge batteries up front and thick wire for positive and grounding leads. obviously most cars don't have this space up front, but if you did, that would more than suffice. a good ground is a good ground, and was the entire point of my post. buying a ton of copper doesn't buy you a better originating ground point to connect it all. ask all the guys here who run 10-15k on 2 runs of 1/0 pos and neg.. or ask the other guys here who added 6 runs of pos and neg and gained a tenth of a volt. and that was probably because they didn't have solid, clean connections/ground points in the first place and got that tenth of a volt by accident. nevertheless, i respect your opinion and we shall agree to disagree.

 

[tommyk90 5,000+ posts]

I am not sure how to "load a ground". you were right earlier when you said electricity is a two way street, but i am not sure you fully understand why that is. I am a mechanic, I have dealt with multiple alternator setups on tractors and heavy equipment. It is completely relevant for that reason, these machines are drawing 600+ amps on 12-24 volt systems. They dont have wiring runs from front to back and batteries all over. simply huge batteries up front and thick wire for positive and grounding leads. obviously most cars don't have this space up front, but if you did, that would more than suffice. a good ground is a good ground, and was the entire point of my post. buying a ton of copper doesn't buy you a better originating ground point to connect it all. ask all the guys here who run 10-15k on 2 runs of 1/0 pos and neg.. or ask the other guys here who added 6 runs of pos and neg and gained a tenth of a volt. and that was probably because they didn't have solid, clean connections/ground points in the first place and got that tenth of a volt by accident. nevertheless, i respect your opinion and we shall agree to disagree.

As stated, comparing a vehicle to heavy equipment is not even in the same league. One of the main reasons being that the frames on those vehicles are SUBSTANTIALLY thicker and larger than a normal vehicle. Thus they are built to handle the current. And thats why I also stated that if you have a full frame vehicle with upgraded underhood wiring then most likely a direct negative lead isn't necessary. But for unibody cars, which is a lot of them, chances are good that a full 1/0 run from the alternator to the rear can help. This is, of course, if the other criteria are met.

People who have massive banks of batts in the back aren't going to benefit as much, if at all, from upgraded wiring because a majority of their capacity is coming from the rear bank and not from the alt or front battery.

When I mean "load a ground", I mean that you have to actually pull current through the material in order to determine if it's a sufficient ground for the equipment you are trying to run. Just because the continuity is low doesn't mean that it's capable of handling the "load" you want to put on it.

On top of that, the equipment you are trying to run will also react differently. On heavy equipment you are running generators or pumps or other industrial machinery and electronics built ridiculously tough to handle the environment. In a vehicle we are running sensitive electronics that can completely burn up if you drop the voltage too low or send a bad signal. I've personally had amps go into protect (luckily) because of a bad ground that was sufficient for the amp I was running previously.

I don't run a chassis ground in my daily driver and that setup is capable of 3kw. Direct 1/0 leads from the front battery/alternator to the rear batteries. Then again I come from an SPL competition background where every tenth (of a volt and of a dB) counts, so I might do things a little differently than your average consumer.

FYI, what do YOU think the originating ground point is? HINT: It's not the chassis. The chassis is just a medium for the battery/alternator, which is why the "shorter the better" ground theory is just a myth. People who add wiring most likely aren't going to gain any voltage if what they had before was sufficient. What they are trying to gain is CAPACITY. If you have a 300 amp alt up front along with a good size battery, one long run of 1/0 isn't going to handle that much current without resistance. This is why multiple runs benefit those people. They aren't going for a voltage increase. I can run one run of 8 gauge and have the same voltage as my 2 runs of 1/0.

There are people on both sides of the fence here. Ones that gained (quite a lot in some cases) and ones that didn't. I'm under the "more is better" group. It really all just boils down to the vehicle, equipment and the person hooking everything up. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

Summary: If you have the money, do it. It certainly won't hurt. //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif