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battery in trunk

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Old 08-17-2015, 04:32 PM
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Default battery in trunk

Not sure what forum this belongs, but...


Going to be re-locating the battery to the trunk. I am looking for ideas/options on how to terminate the cable end in the engine bay.


I was thinking about some sort of junction box on the firewall that was convenient to the starter. Then also having some smaller terminals for attaching other hot wires...


What about the ground? Seems like some of the kits provide a short cable to attach to the body. I would think running the cable to the engine bay would be a better option...


Thoughts?
thanks.
Old 08-18-2015, 08:22 AM
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A ground is supposed to be as short as possible, that's why it comes with a short cable. Not sure how people terminate the positive cable as I've never run a rear mounted battery. I would assume it terminates at the starter though.
Old 08-18-2015, 09:28 AM
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X2, direct to the starter. You can pull a smaller gauge wire from there to feed everything else.

Ground the neg to the frame rail in trunk.
Old 08-18-2015, 12:03 PM
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I know most don't have any type of fuse on their pos+ wire from the starter to the battery. But I've been thinking lately that I might want to fuse it. Seems like it would be a fail safe for the starter if it were to short out during starting. am I wrong?
Old 08-18-2015, 12:32 PM
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Dont think thats a major concern. Im not aware if anyone or OEM that does that.

I think that if an internal short would occur, the internal wires would just disintegrate...end of story.
Old 08-18-2015, 04:47 PM
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Originally Posted by N20zuki
A ground is supposed to be as short as possible, that's why it comes with a short cable. Not sure how people terminate the positive cable as I've never run a rear mounted battery. I would assume it terminates at the starter though.

I don't totally agree with your response . Yes, a shorter path to ground is desirable. But copper is a much better conductor than the cars frame. So if the cable was terminated up front with some sort of junction box, the path for a circuit to go to ground would be quicker through the copper cable than through the car chassis to some short ground cable mounted in the trunk.


In reality, the difference between the two is small, but noteworthy. And for all practical purposes probably not an issue...


Thanks for all the replies, I am beginning to develop a plan...


One other thing. Running the hot directly to the starter is not a bad idea, if you are confident that you will never drop a wrench that lands between the starter lug and the headers... move quickly to put out the ensuing fire... Ford has a better idea. They use a solenoid to supply full current to the starter only when it is being turned over - much safer in my opinion and my clumsiness.

Last edited by lowcountry; 08-18-2015 at 04:56 PM.
Old 08-18-2015, 07:20 PM
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Also worth mentioning for LS1 swappers, don't run 12v constant for the PCM to the starter. The PCM needs 12.4v or it won't send the signal to fire. When your battery gets tired you'll get starting problems.
Old 08-18-2015, 08:08 PM
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Originally Posted by lowcountry
I don't totally agree with your response . Yes, a shorter path to ground is desirable. But copper is a much better conductor than the cars frame. So if the cable was terminated up front with some sort of junction box, the path for a circuit to go to ground would be quicker through the copper cable than through the car chassis to some short ground cable mounted in the trunk.

Except the fact everything in the car is grounded to the chassis... so therefore it's a waste of money, and time since your still going to ground it to the car. It's the shortest path of resistance, not to mention the amount of electrical frequency you will pickup with your cars radio. 15ft of copper wire vs steel body of the frame, your going to build heat in the cable and still terminating it to the chassis.

Last edited by N20zuki; 08-18-2015 at 08:20 PM.
Old 08-19-2015, 10:13 AM
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This is how i solved the wiring when i moved my batt to the trunk.

Ground- i have two wires from batt, one short in trunk and one long going in parallel with + wire to the front and this one is connected to ground together with the origin ground from starter.

Old 08-19-2015, 11:18 AM
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Lithium battery up front, way better option. 4.5lbs and about 1/4 the size.
Old 08-24-2015, 03:38 PM
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This is how I did my relocation


Old 08-28-2015, 08:57 PM
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Good call on the lithium battery if you have the $$$. Jegs has them for $500+.



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