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Discussion Starter · #2 ·
Re: Relocate Battery? (Revolve40)

This easy? <A HREF="http://www.jegs.com/i/JEGS/555/10262/10002/-1" TARGET="_blank">http://www.jegs.com/i/JEGS/555/10262/10002/-1</A>
 

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Re: Relocate Battery? (Revolve40)

Uh no lol. Problem i foresee is that we cant just run a positive cable like a normal car you also need to run a ground. Normally the ones ive done i just ran a short ground cable from the battery to a good spot on the trunk floor. However on our cars i would run a ground thru the car to the ground post in the engine bay to make sure you have ample grounding.<p>Running two cables thru a very tightly made car would be a biotch.<p>I was planning on doing this so i could mount my ECU in the battery box and use it as a cooler. After looking at it though just seemed like more of a pain in the ass.
 

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Discussion Starter · #4 ·
Re: Relocate Battery? (ForceFed Motorsports)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD><i>Quote, originally posted by <b>ForceFed Motorsports</b> »</i></TD></TR><TR><TD CLASS="quote">I was planning on doing this so i could mount my ECU in the battery box and use it as a cooler. After looking at it though just seemed like more of a pain in the ass.</TD></TR></TABLE><p>I'm looking to do nearly the same thing. Except I want to use the battery box as a filter housing and an ECU cooler. So you really don't think it's a good idea?
 

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Re: Relocate Battery? (Revolve40)

A ground is a ground regardless of where it is on the car so you would only need the positive cable and just a short ground cable to a good point in the trunk. That said, not sure how easy it would be to run just one cable back to the engine bay?
 

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Re: Relocate Battery? (Revolve40)

Just seemed like more work than simply making a seperate ecu box with fans. <p>As for the ground i understand that the entire body is a ground however when you have all of you major body functions using the front half of the car for grounding seems like grounding to the trunk wouldnt be sufficient.
 

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Re: Relocate Battery? (ForceFed Motorsports)

The entire ground is electrically equivalent. Agreed, sounds like more work than a seperate box for the ECU, guess it depends on what your goal is and how far your willing to go? <p>If anyone is interested in prooving the electrical theory you can quickly verify it if you have a mulitmeter. <p>Just take a wire that is long enough to reach between the engine bay ground point and your point in the trunk, connect the engine bay side to the ground and connect the trunk side to the wire and ground and measure the resistance. Next measure the resistance of the test wire and subtract it from the test result for your resistance between the two grounds. Finally for confirmation test a ground point as close as possible to the engine bay ground with the meter and they should be the same.
 

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When wiring up your new battery, do also consider the amount of current that you would like the battery to provide. The more current, the thicker the wires, just like how thick jumper cables are. Is there really space to run that thick cables from the front to the back of the car?
 

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Re: Relocate Battery? (Revolve40)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD><i>Quote, originally posted by <b>Revolve40</b> »</i></TD></TR><TR><TD CLASS="quote"><p>I'm looking to do nearly the same thing. Except I want to use the battery box as a filter housing and an ECU cooler. So you really don't think it's a good idea?</TD></TR></TABLE><br>Hmm that's an interesting proposition...<p>I'd do it if I wasn't lazy I suppose! Besides, should be an insurance break, too!
 

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Discussion Starter · #10 ·
Re: Relocate Battery? (BtownVolvo)

Well, I'm determined to do this. Can you guys give me a little more info on why our batteries can't be relocated like any other battery? Thanks.
 

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Re: Relocate Battery? (Revolve40)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD><i>Quote, originally posted by <b>Revolve40</b> »</i></TD></TR><TR><TD CLASS="quote">Well, I'm determined to do this. Can you guys give me a little more info on why our batteries can't be relocated like any other battery? Thanks.</TD></TR></TABLE><br>Don't see why you can't. It's not like it's different from any other car. I was going to do it on my car. I say do it!
 

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Re: Relocate Battery? (slrising)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD><i>Quote, originally posted by <b>slrising</b> »</i></TD></TR><TR><TD CLASS="quote">A ground is a ground regardless of where it is on the car</TD></TR></TABLE><br>False! The resistance of the positive cable and frame itself will affect many things. It's not a trivial thing to relocate the battery that far away in a modern car, let alone ours. Trust me, the electronics under the hood will notice.<p>This is not to say it can't be done. Just don't expect it to be as easy as a fat cable and sanding off a bare spot in the trunk.<p>Don't forget about venting the fumes, btw. Be sure they have a way out.<p>Tom.
 

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Discussion Starter · #13 ·
Re: Relocate Battery? (tmtalpey)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD><i>Quote, originally posted by <b>tmtalpey</b> »</i></TD></TR><TR><TD CLASS="quote">This is not to say it can't be done. Just don't expect it to be as easy as a fat cable and sanding off a bare spot in the trunk.</TD></TR></TABLE><p>Thanks for the information. However, a lot of it is Greek to me. I'm a car guy, but when it comes to electronics I might as well be driving a Model T. You say it will be more difficult (which is fine, I love a challenge), but I still don't really know what will be different about the relocation. Sorry folks, thanks for your patience though.
 

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I can't imagine the resistance will be noticeable enough to make a difference. But that's my $.02<p>As far as ground, just grind down a spot in the trunk or run it through and ground it to the chassis.
 

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Re: Relocate Battery? (Revolve40)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD><i>Quote, originally posted by <b>Revolve40</b> »</i></TD></TR><TR><TD CLASS="quote"> but I still don't really know what will be different about the relocation. Sorry folks, thanks for your patience though. </TD></TR></TABLE><p>Let me try to explain in simple terms. I'm not good at explaining, but here it goes:<p>In electrical circuits, there is something known as resistance - an opposition to the flow of electrical current. For example, a piece of gold or copper wire (as you know by common knowledge to be good electrical conductors), have a low resistance, allowing for electricity to flow freely through the wire. However, a piece of wood, for example, does not allow electricity to flow through it easily, therefore it has high resistance.<p>So by simply putting the battery in the back of the car and tying the ground to the chassis, you are forcing all the electricity to go from the battery, through a positive wire that you routed through the car, to the engine, and then back to the battery through pretty much the entire chassis of the car. This is a much higher resistance path for the electricity to travel than if the battery was simply in the engine bay. <p>And the issue with resistance is that the higher resistance you have, the less current can be in the circuit. And, um, you can say current is how much power the battery can deliver, and its measured in Amps. Basically, the more resistance you have in a circuit, the lower amperage you can deliver. So by relocating to the back and tying the ground to the body, you may not have as much "power" in your battery. <p>So you say, I'll bring two wires, a positive and ground, to the trunk of the car. Well, to deliver all the power, or current, of the battery the wires will have to be thick (Very thick - 8 gauge, probably more). If you use thin wires, the problem is that when high current is sent through thin wires, the wires can overheat, melt the plastic sheathing on the wire, and short circuit with other connections here and there, and even catch on fire. And also, the longer wires you have, the higher resistance the connections are. So you would need a very thick gauge (wire thickness is measured in a standard called gauge if ya didn't know) to prevent overheating while being able to deliver the amperage the engine needs to crank, etc. The issue with that is how will you route two finger thick wires throughout your car to the trunk? Then there is the issue of venting the battery so you don't have corrosive gases floating around the trunk. <p><br>Sorry about the weird explanation. I just got up and haven't had coffee. If you get what I'm saying, great. If not, I'll come back and try again. But basically, if you tie the ground to the trunk, the resistance will be too high to deliver all the amperage that is needed for cranking, etc. And if you bring both ground and positive to the trunk, you would need to use an extremely low gauge wire to prevent overheating/fires/shorts while being able to provide all those nice juicy cranking amps.
 

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Re: (BtownVolvo)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD><i>Quote, originally posted by <b>BtownVolvo</b> »</i></TD></TR><TR><TD CLASS="quote">I can't imagine the resistance will be noticeable enough to make a difference. But that's my $.02<p>As far as ground, just grind down a spot in the trunk or run it through and ground it to the chassis.</TD></TR></TABLE><p>You have two wires. One is 30 gauge (hair thick), one is 6 gauge (thumb thick). The resistance on both is equal (say one ohm). <p>You think you can hook your battery up to the 30 gauge wire to the car and have it start? <IMG NAME="icon" SRC="http://www.vwvortex.com/vwbb/wink.gif" BORDER="0"><p>
 

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Re: (BtownVolvo)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD><i>Quote, originally posted by <b>BtownVolvo</b> »</i></TD></TR><TR><TD CLASS="quote">I can't imagine the resistance will be noticeable enough to make a difference. But that's my $.02.</TD></TR></TABLE><p>You ever done a voltage drop test on the cable to the starter wire <IMG NAME="icon" SRC="http://www.vwvortex.com/vwbb/wink.gif" BORDER="0"> Ive seen hard starts be caused just from having a rotten cable with too much resistance. Im not saying that relocating the battery is impossible but for how much electronics are in the car and the fact that 80% of the electrical need is in the engine bay now has to travel thru a 8 foot cable worries me lol.
 

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This was all assuming using something around 4 gauge wire. <p>That's where we're getting confused.<p>No one in their right mind would keep the same gauge wire.
 

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Re: (vivek9856)

There are two issues here with the wires.<p>First is the resistance of the wire, how much resistance of the wires would affect the actual car circuit. This actually depends on how much resistance the car has during operation and during ignition. I would not think this is very significant here as car electronics are supposed to work with the minimum 12V with tolerance level above that due to surge in voltage when reving and ignition. The car battery comes to about 14V to 15V usually (assuming not nearing end of battery life or low battery). So unless your new wire takes up like 1/6 the resistance of the existing circuit, it will not cause the car to function properly.<p>Second is the need to carry enough currents. The thing you want to blow is your fuse, not have your wires burn from carrying too much current. The current now you are concern with is how much current there is when the alternator charges the battery, during ignition and when the engine is off, but the radio and stuff are switched on. All these currents should not exceed the rating for the wire (preferably to have some more safety overhead on the wires than the maximum).
 

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Re: Relocate Battery? (ForceFed Motorsports)

Actually If You get the Connection or Terminal Blocks and Trunk Parts from a A5 Audi It will Be Easier and Super Clean .<p>Trunk Parts Like the Brass Thur Truck Hole Connection etc. , Run It on the Out Side Next to & Just Behind the Exhaust Shielding . <IMG NAME="icon" SRC="http://www.vwvortex.com/vwbb/cool.gif" BORDER="0"> <BR><BR>
<i>Modified by EngTech at 6:44 AM 6-6-2009</i>
 
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