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Battery Relocation

New 3/12/05

Sorry for the multiple emails about my battery woes, you guys are a helpful bunch.

Alright I have a relocation kit and an Odyssey PC1200 in the mail as I am writing this. My question is what is the best way to go about relocating the battery? I saw Paul's article on the site as well as on the forum about running the wires under the car. I am a tad uncomfortable with this route, especially because I am lowered. I would be worried about debris cutting through or tearing the wire out completely. So naturally, the other route would be to route the cable through the firewall, then back to the trunk through the inside. Is it safe to have that running through the passenger compartment? I do plan on adding a circuit breaker to the box for disconnecting convenience and as a safety measure. Is is safe to drill a hole in the firewall if the existing hole is not large enough?

Any other tips or hints greatly appreciated. -- Roman Steichen

If you add a split loom to it I would not worry about running it through the car interior. Use the door sills. Make sure there is plenty of insulation at the opening above the brake pedal. And use a fuse at the battery.


Why a fuse and not a circuit breaker? And by insulation by the brake pedal do you mean a few layers of the split loom?

Fuses are cheap, sure and reliable. www.waytekwire.com  has 250A fuses ( 46276) for under $4 each and a holder ( 46039) for ~$6.

Do you have a 250 A cb?


> Do you have a 250 A cb?

Pardon my ignorance. What is that?

I used two layers of split loom insulation and yes you need to zip tie it. If I were to do it again I would run it through the firewall at the master cylinder area and then down the passenger side door sill. Still using the two layers of split loom.


Since I am looking to upgrade the stereo setup I think I am going to need the sills on both sides for cables. 3 linked changers and a new amp or two with a custom head unit install. So I think under the car is going to be my best bet.

Great stuff Paul. This is very timely since I was under the hood for the first time in a long time and really got a good look and now really want to place the battery in the trunk as well. It's just too cramped at the intake side.

Questions about running the wiring under the car. Is split loom the only extra sheathing or protection under there? Is more needed or overkill? Did you find it necessary to zip tie a few spots and/or would one need some slack for unintended movement across the entire length of the car? Does the battery box need to breathe or can one use a sealed one? No experience with this here and looking to do it once the weather breaks.


I would run the pre amp stuff on one side and the 12V power on the other.

You will be getting the amp power from the trunk you know.....


My 02 wire is fed through the big firewall grommet and run under the door threshold cover to the trunk.

Carter Fuji


I thought this made it up onto V8SHO.com long ago, but I can't find it there. Read it and also read Paul's write-up. http://www.v8sho.com/SHO/batteryrelocation.html

That's true. The door sills will be full however with 3 sets of RCA's on one side and 3 sets of the Unilink multi-pin cables. Unless I can find a Unilink adapter and extension to run the module from the trunk and only have to run 1 cable extension to the head unit.

That's one of the reasons upgrading the head unit isn't done that often. I would install the amps using the factory RCU in the trunk. The factory RCU actually has very good SQ when coupled with good speakers. If the SQ still isn't to your liking a good parametric EQ can improve the sound quite a bit while retaining the stock head unit and leaving all the wires in the trunk.

The main reason upgrading isn't done that often is that Ford integrated this thing with the ECC and made it a real PITA for everyone. I have different needs for a stereo setup. I'm not a stereo head but I like changers that work, speakers that are decent that won't overwork the amps, and the ability to use cd's in the head unit. Just a personal quirk for me. The parametric EQ is an interesting though though. Believe me, if the oem setup didn't make me bonkers I'd love to just leave it alone. I have enough ongoing maintenance with this baby. ;)

I was so used to changing CDs from the cockpit in my old cars that I thought about hacking the dash to put in one of my spare HUs. All of the '96-99 aftermarket installs I've seen, however, look like s___ (no offense to those who have spent time & money to do it) including the manual climate control "football" kits that they sell for the SLOs. There's just no proper place for a rectangular HU with the oval interior of the car.

I thought about giving up some console storage space and mounting an aftermarket HU vertically in there, but then I'd need to open the lid every time I wanted to adjust the volume or choose a new track.

How about cramming the stock changer in the console space? I'm sure extension cables can be sourced for our stock wiring. You can get 10-disc changers that work with the stock RCU/HU. 10-discs at your fingertips, yet out of sight, would be nice. My console just turns into a bucket of spare change, gas station receipts, pens, cell phone charger wires, etc. within 2 days after I clean it out anyway. I probably wouldn't miss it much.



Thanks to anyone who offered help.

The duct tape is to cover up a hole I made in the carpet while trying to run a strap through to hold the box down. I gave up on the strap idea and went with screws. Seems to be holding it down okay.

In the trunk, I grounded the negative wires to the original battery tray holes. I grounded in the trunk to the same bolt Paul and Roman used (paint grinded away first, of course).

Don't worry, I used split loom insulation on the positive wire the entire way (two layers in the engine compartment) except for the section you can see. I ran the wire through the firewall grommet and under the passenger side door sill panels.

The positive connection under the hood is covered up with electrical tape for the time being. I ran out, but might get some more to cover all exposed wire.


On Apr 10, 2005, at 5:17 PM, Jim wrote:

Have you considered putting it into a marine style sealed box and running a vent outside? Maybe down through the hole the tape is  covering?

Actually, it's in a marine style box without the lid on. I've seen sealed box setups before without a (visible) vent. If I did this I would just run some sort of tubing through the trunk floor?


Exactly. This will protect the wiring in your trunk (tail lights, stereo pieces) from hydrochloric acid fumes. You might consider setting a couple of shiny pennies on the battery too as sacrificial metal for the fumes.


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