Battery relocation

J_lope82

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Hello folks. I’m looking to relocate my battery to the trunk. I will be using 1ga wire. Also a circuit breaker on the positive wire at the trunk. I’ll be using a plastic battery box for now.
From you all experience what advice would you all give? What’s a good route to run my wire. Any safety measures to follow?
 

cobrajeff96

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Just keep it away from anything moving and anything hot. General rule of thumb is at least half a foot from anything hot and in that case the wire/hose/etc should be covered in some type of heat resistant sheath like those fiberglass woven spark plug protectors. I might even go father and cover it in that as well as the corrugated seamless aluminized tubing.

More than one way to slice the pie, and there's tons of examples in google images or mustang forums, etc. Did the trunk relo a few years back and while I'll post pics for examples, I honestly threw money at it and it's not for everyone on a budget. I have + running down driver side and - down passenger. All 1/0 AWG or 0 gauge or 50mm squared.

It's a Varley red top 60 with a custom aluminum hold down (pictured), 500A main breaker (pictured), a + distribution point up front (not pictured) with one leg going unfused to the starter and the other leg going to everything else (300A fused toward OEM fuse box and the alternator). Negative trunk goes from the IRS subframe onto a distribution point up front (not pictured) and branches off with one to the passenger motor mount and to the case of the alternator.
 

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RAU03MACH

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Hello folks. I’m looking to relocate my battery to the trunk. I will be using 1ga wire. Also a circuit breaker on the positive wire at the trunk. I’ll be using a plastic battery box for now.
From you all experience what advice would you all give? What’s a good route to run my wire. Any safety measures to follow?
Easy
 

ttocs

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If you run it under the car be sure it is hard mounted every couple of feet. Not with zipties but screw down clamps/holders. If it gets close to anything hot you can get heat wrap insulation to protect it but stay as far away as you can from the exhaust again if it is under the car. I still disagree with Jeff that the wire he has will melt before that 500A breaker trips because it is too big but to each his own. I have a 250 amp fuse on mine.
 

ttocs

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Also do not look for bargins on wire as there is a HUGE difference. On the cheap wire you will find the insulation is 2x as thick and the wire 1/2 as much as it should be.
 

RAU03MACH

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Just make sure to get enough cable
You will only need 4 foot of black ground
And the length of the car in red pos+
 

cobrajeff96

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I still disagree with Jeff that the wire he has will melt before that 500A breaker trips because it is too big but to each his own. I have a 250 amp fuse on mine.
I'd have to say I disagree with you. The battery used here has over 800 cranking amps. Any direct short to ground with all that energy will surely blow a 500A fuse before a 1/0 wire melts. FWIW, some years ago a 300A mega fuse I had installed was blowing every time the key was cranked. Then I started looking at the actual data sheet that accompanied the starter I bought and installed. The more you know. And this main breaker is sized just about 20% over max starter current, and also placed within very close proximity to the battery itself as it should be.

As you can see from here, I am well within my means.(Cable Lengths) Wire Load Amperage Chart.JPG
 
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ttocs

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do a quick search on the max amperage rating for 1/0 and see if that changes your answer. Yes that battery is absolutely able to supply more current than the cable can handle, and that is why the breaker/fuse is used. If that cable shorts out I doubt the breaker will trip before the cable melts. Ever seen people hook up jumper cables backwards - it will be the same only much bigger since they are usually 8 awg.
 

cobrajeff96

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The first Google result you see is not going to cut it. You're forgetting distance, voltage, and temperature factors. And it depends on where you get your info too. Different sources of information do not agree with one another. It's all a judgement call, but I actually have real-world example to base this from so I'm good. I'll sleep at night.
 

ttocs

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oh man sorry I forgot MSM :) I welcome you to show where 1/0 is rated for 500 amps. Everything I show says it is significantly lower.
 

cobrajeff96

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You'll have to do better than the first Google result that you see. Keep looking.

Try adding a 12vdc search term. Get creative. There's more to this.

Don't forget about voltage, temperature, and distance. Continuous vs. intermittent. Etc.
 

cobrajeff96

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You do what you do, and I do what I do. If you name-drop me, I'm going to respond. Feeding you links won't change your mind, I foresee, for two reasons:

1) Different sources are not in agreement with one another so it's a moot argument.
2) I won't do for you what you could (and should) do for yourself.
 

ttocs

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Sounds good jeff.


OP: you really want to run the smallest fuse you can get by with for the rating on the cable in case it shorts out so the fuse/breaker will blow as quick as possible. When I started off I put a 200 amp fuse in mine and it popped it when cranking, so I upped it to a 250 and it has been fine since. Unless you are running some really high compression motor the starter should not need to be pulling that much more current 250 amps is a shitload of current.
 
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J_lope82

J_lope82

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thanks for all the info guys, and good topic to discuss because I’m still undecided about what size breaker to install. If I remember correctly shouldn’t you set your safeguard(fuse or breaker) 10-20% above your highest amp drawing?

Not sure what the starters normally draw.
 
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J_lope82

J_lope82

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I'd have to say I disagree with you. The battery used here has over 800 cranking amps. Any direct short to ground with all that energy will surely blow a 500A fuse before a 1/0 wire melts. FWIW, some years ago a 300A mega fuse I had installed was blowing every time the key was cranked. Then I started looking at the actual data sheet that accompanied the starter I bought and installed. The more you know. And this main breaker is sized just about 20% over max starter current, and also placed within very close proximity to the battery itself as it should be.

As you can see from here, I am well within my means.View attachment 28451
This chart is great for sizing your wire according the the length and amperage you will need correct?
 

ttocs

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you set your breaker/fuse according to the wire you run. You pick the wire depending on the max rating on the equipment and yes adding %20 is not a problem.
 
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J_lope82

J_lope82

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The only thing I am not sure of is how much amperage the starter draws under normal operating conditions.
I focus on the starter because that would be the biggest load on the system.
 

RAU03MACH

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If you have a good starter you should ok
But install a cable to engine block and chassis NEG
Then on the rear install a cable to chassis to NEG terminal in trunk to battery good solid ground

The red from fuse box to under chassis to breaker in trunk to battery pos
 

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