2 runs of power and ground from under the hood theory

[sinosic 10+ year member]

i read that alot of people run 2 power and 2 ground wires from the hood to the back. from what i understand that isnt needed and just a waste of money. doesnt electricty take the path with least resistance? if so it would choose the wire with the least resistance outa the 2, leaving the other useless. right?

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[CRXBMPN 5,000+ posts]

im sure there is more total current being sent through two wires than there would be one, regardless of the path of least resistance.

 

[sinosic 10+ year member]

huh. i wonder if one of the wires is not big enough for the amount of current, the over flow or the rest of the current goes threw the other wire. if a wire has alot of current then the other would then have least resistance.... all i know is this shit is confusing

 

[mokedaddy 5,000+ posts]

I have two runs of each just because I have two batteries in the trunk and current draw in the neighborhood of 450 amps max.

I know I could probably get by with one as the current draw rarely, if ever gets that high but I would rather have the peace of mind knowing my wire can handle all the current I would need for my application.

 

[joetama 5,000+ posts]

I think you need to do a little research on how electricity flows...

What dictates which wire will get more current is resistance. Most likely one cable (if longer or different gauge etc) will have a slight difference in resistance. But, this difference is going to be so small it will be insignificant.

For example, if you have one cable carrying 100 Amps by adding a second cable each cable would carry 50 amps. This is in a 'perfect' situation. The more amperage you draw the more voltage drop you will have. SO, by having more cable you have more potential to pull amperage so you will have less of a voltage drop (due to lowering resistance).

If one path has less resistance all the energy doesn't flow down that path. //content.invisioncic.com/y282845/emoticons/fyi.gif.9f1f679348da7204ce960cfc74bca8e0.gif

 

[helotaxi 5,000+ posts]

Current flows in both wires in inverse proportion to the resistance of each. Unless you have some really crappy connections, the current through each wire should be roughly equal assuming that they are wired in parallel and are the same size.

 

[Brian Owens 10+ year member]

Current is divided between the wires. . .

It is all about voltage drop. Wire has a resistance. Voltage = current x resistance

When you divide the current between the wires, you have less voltage drop. . .

 

[sinosic 10+ year member]

wow thanks alot you guys really helped me out. i ques i need to get more wire. thanks for your help

 

[joetama 5,000+ posts]

Current is divided between the wires. . .
It is all about voltage drop. Wire has a resistance. Voltage = current x resistance

When you divide the current between the wires, you have less voltage drop. . .

I

 

[joetama 5,000+ posts]

wow thanks alot you guys really helped me out. i ques i need to get more wire. thanks for your help

What wire are you currently running?

It might be easier for you to upgrade the gauge.

 

[lostdaytomorrow 10+ year member]

If you're not running over 200 amps of current, 1 positive wire (0/1 awg)and 1 good ground in the back to the frame should suffice most likely, but of course the ground depends on the car and how the frame is made.