Battery relocation

cobrajeff96

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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.
Most Ford starters max out at 350A, but it depends on lots of things like compression ratio, reciprocating weight, current temperature, maybe even the oil weight but now we're just splitting hairs. FWIW, these cars from the factory are not fused on the starter wire. I'm not sure about these days, but I'd go so far as to say that most cars from this era just have a hot, unfused lead going to the starter motor. What I did was overkill, TBH.

If you stick a 1/0 wire (which is a pretty popular route to go) you won't be losing out. I recommend BatteryCableUSA. I've never "melted a wire" as some might say. Again, I found this and other data sets years ago and I use them for reference whenever necessary...

(Cable Lengths) Wire Load Amperage Chart.JPG

And you know what? Fk it... next time I'm with the car I'm gonna shut off the fuel pump and crank the starter motor for 20 seconds straight, then I'll immediately get underneath and put bare hands down all lengths of the hot wire, see if it gets too warm for peace of mind. We'll put this side-debate to rest then.
 

lwarrior1016

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Man, I run a 4/0 cable power and ground from my trunk to the engine. It turned my 13:1 compression 2 valve and now turns my 12.5:1 compression coyote. The wire is inside the rocker panel of the car and over no sharp edges. I have power and ground from the battery to the starter and block respectively. It’s been this way since 2016 and I’ve got A LOT of miles on it.

I have no breaker or fuse.

If your car doesn’t start, don’t hold the key and load the starter excessively. You know if there is a problem.

We can “what if” this topic to death, but the truth is, there are many problems that can arise by moving the battery, and there is no 1 correct way to do it.


I tried to keep my power distribution close to the stock setup. I’ve got power straight to the starter, and a power wire from the starter to the fuse box. Then power from the fuse box to the alternator. I’ve got ground from battery to motor mount bolt, then ground from a transmission bolt to chassis. Everything works great.
 
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J_lope82

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Do you all see any issue with running the positive wire through the inside of the car?
 

lwarrior1016

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Do you all see any issue with running the positive wire through the inside of the car?
The only issue I had with inside the car, was fitting that large cable under the carpet. I have pictures in my build thread somewhere around 2016, but mine goes in the rocker in the passenger wheel well and into the car under the rear seat. I think @white95 has his that way and may have pictures.
 

white95

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The only issue I had with inside the car, was fitting that large cable under the carpet. I have pictures in my build thread somewhere around 2016, but mine goes in the rocker in the passenger wheel well and into the car under the rear seat. I think @white95 has his that way and may have pictures.

48488322666_60546923af_o.jpeg48417257781_d2be74b882_o.jpeg48466929392_890bc4a09c_o.jpeg
 

ttocs

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I ran mine inside as much as possible. The carpet will not burn if it is fused correctly. If not then as I said be prepared to hard mount them to the body as often as possible. Copper cable is not light and it will fall down if the mounts fail.
 

Wmac

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Just completed a relocation to the trunk this summer, also ran the cable thru the interior and out the firewall.

Bought a moroso plastic box, Allstar disconnect switch and 2 x 25' lengths of 1 ga welding cable. Plus terminals, cable cutter, crimper, shrink tubing, grommets, hole saws, etc, etc.

More difficult and expensive than anticipated. But it functions and should be NHRA compliant.

Suggest mocking it up before you drill any holes. Make certain you can actually get the battery in and out of the box once the box is bolted down.

20230830_141036.jpg20230830_140902.jpg
 

cobrajeff96

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I personally would never run thick +/- cables inside the cabin but that's just me. Like I said in my first reply, there's more than one way to slice the pie here. No one's wrong... unless their car catches fire from a lazy design. And there are actually good reasons for at least some portion of the cables to be ran inside the car, such as certain sanctioning bodies requiring a master disconnect within easy reach so that track staff can reach inside your window and kill your car. Some require it on the outside of the car, near the trunk. Just depends on the event class, etc. These days, if you got a little extra coin, you can run a low-voltage disconnect which'll essentially just be a type of relay inside the car that lets you safely kill the power source and not have it directly inline with huge current - saves space for sure because no need to have the big cables inside the cabin.

Me, personally my car will likely never see any sanctioned track. It's not my thing, at least with this car. The downside to running cables inside the car is increased footprint, complex obstacle routing, fumes/outgassing when the cable is still new, sharp unfinished edges, etc.

Zip ties while fine are not ideal, whether it's inside or outside the car, but if they are thick enough then they will suffice. Cushioned clamps (or Adel Clamps as they are called) are ideal. Hellerman-Tyton also makes some excellent cable/hose anchors and I use a few of them on the car.
 

cobrajeff96

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This chart is great for sizing your wire according the the length and amperage you will need correct?
Yes, you do not need a monster cable running up and down the length of the car (1/0 is already quite beefy, trust me). Anything more is just hypothetical added insurance. There's no way you're going to "melt" a 1/0 cable with common loads these cars experience. Now... if you're quading out with ten 15" subs and five amps, that's a whole nother story and the car's entire electrical system will change anyways.
 
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J_lope82

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The goal for my car is just to be a well performing and clean street car. I don’t have plans to race it in any events with rules and stuff.

So now what is you all’s experience with the circuit breaker or fuse size? What sizes work well from you all experience. I know everyone has a different opinion on this topic but I just want to know what has worked for you all, TIA.
 

ttocs

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Breakers are more convenient for the short term, but the moving parts inside can eventually start to wear down and they can become easier to trip over time. The shock/vibration that cars experience also isn't great for them.
 

cobrajeff96

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The goal for my car is just to be a well performing and clean street car. I don’t have plans to race it in any events with rules and stuff.

So now what is you all’s experience with the circuit breaker or fuse size? What sizes work well from you all experience. I know everyone has a different opinion on this topic but I just want to know what has worked for you all, TIA.
With this, there's again more than one way to slice the pie. Realistically for a street car that doesn't experience routine abuse, no fuse link is necessary. If the wire is sufficiently separated from impact zones, heat sources, and moving parts, just run it like factory and save yourself time/money/headache. If any of those things start to become concerns, then start thinking about different ways to overcome them. Example, if trunk cable (heavy gauge direct to battery) lies in an area that is potentially shorted even with a light impact with another car or something stationary, then fuse it close to the battery as possible.

You can get pretty exotic with this or keep it simple. Simplest is just a bolt-down Mega fuse or something like that. When current exceeds the fuse rating, it breaks and you install a new fuse. A breaker is a mechanical means of resetting the link when broken, so it's easier in the long term and also nice for testing/troubleshooting because you can lock-out the power at any time. Then there's solid state: no moving parts, it's more like an integrated circuit and some of them can handle big juice. They can even be programmed for time-delay on/off functions depending on what you're needing. I've got a 270A SS relay in my car solely for the Coyote swap electronics and also it acts as an anti-theft module the way I have it set up. It'll handle big surges or voltage drops if anything unforeseen happens, and it'll literally last forever because of no moving parts to wear out.

In my opinion, stick with the bolt-down fuse. If you decide to throw money at the car, skip the breaker and go straight to a SS relay. You either go full retard or you don't, in my view.
 

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95opal

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Man, I run a 4/0 cable power and ground from my trunk to the engine. It turned my 13:1 compression 2 valve and now turns my 12.5:1 compression coyote. The wire is inside the rocker panel of the car and over no sharp edges. I have power and ground from the battery to the starter and block respectively. It’s been this way since 2016 and I’ve got A LOT of miles on it.

I have no breaker or fuse.

If your car doesn’t start, don’t hold the key and load the starter excessively. You know if there is a problem.

We can “what if” this topic to death, but the truth is, there are many problems that can arise by moving the battery, and there is no 1 correct way to do it.


I tried to keep my power distribution close to the stock setup. I’ve got power straight to the starter, and a power wire from the starter to the fuse box. Then power from the fuse box to the alternator. I’ve got ground from battery to motor mount bolt, then ground from a transmission bolt to chassis. Everything works great.

That is how ive been doing it for 30 years or so. Never had any issues.
 

ttocs

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the team-no-fuse cars were easy to spot when they came into the shop. There was a black line burned in the carpet from the point it shorted out to the battery. Worst I ever saw was only for some 8 awg and the guy sent a screw through it years after it was installed and he forgot about it. He said about 10 secs after he did it he started to smell smoke and then noticed the wire glowing.
 

cobrajeff96

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That is how ive been doing it for 30 years or so. Never had any issues.
Only thing about it is that it has very little impact protection, if any at all, being inside the rocker panel. I went for getting the cable as far inboard as possible, but alas it's an SN95 so there's only so much leeway.
 

95opal

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Only thing about it is that it has very little impact protection, if any at all, being inside the rocker panel. I went for getting the cable as far inboard as possible, but alas it's an SN95 so there's only so much leeway.

When I said that's the way I've been doing it I meant the routing not the actual placing of the wiring. My cables Run next to the frame rail on the outer side above my stiflers web bracing. I have no worry about anything happening to the power or ground running above that web of bracing.underside.jpg
 

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