Battery Relocation

Written by: RI_cel
Pictures by: RI_cel and Pidster

Disclaimer: I am in no way responsible for any consequences that might happen while modding your car, this document is for educational purposes only.

     I wanted to relocate my battery to my trunk to make room for a CAI, but couldnít really find any good tutorials on how to go about doing it, so I created this to help people in the future. Itís pretty straight forward, and has a good amount of photos to help. Have fun, be smart, and keep modding.

4x Heavy Duty Lug - 4 GA., 5/16" 2pack
Group 24 battery box with strap down
150amp surface mount circuit breaker
2x Footmanís Loop, 2IN Web
Battery Cable - 4GA, Red, about 20 ft.
Small ground wire
Ground fittings and battery box hardware: 3X bolts, washers, wing nuts
Battery terminals

Plan Ahead:
     You want to plan ahead before jumping into this. Fool around, and maneuver your battery box around your trunk a little to find the best possible secure place for it. Make sure you have clearance for your hand to fit the bolts underneath. Also, a large safety part, make sure that you pick a nice place for the battery if in worst case scenario, you crash, the dang thing wonít go flying at your head.

     My 5e-fe, as you notice thereís so little room in there!!

     Start by removing the battery from the car.

     I also removed the stock intake. First remove that ďconeĒ thing by unscrewing it on the left front area of the engine bay. Next, open the filter box and remove the filter. Unscrew the rubber connector      off the throttle body and remove the top of the filter box as well. Inside the filter box there is a screw, along with another one outside of the box behind it and to the right. Take these out. Remove the box, and now you have room to work with.

     After removing the positive lead you want to take a wire brush and just brush off any rush or build up that you may have on it. By adding a longer wire we are creating more resistance, and the less resistance the better.

     Weíre going to take one end of the new positive wire and (being careful) cut the insulation off just enough to fit into the lug. Then once you have fit the wire into the lug, crimp it onto the wire. I didnít have a crimpier so I used a hammer to flatten it to the wire. I still suggest using a crimper. Next, take your electrical tape and cover over the wire side of the lug to protect from any other contact it might encounter.

     As you can see, I have taken the old positive terminals and connected them to the new one. I covered them with electrical tape AS A TEMPORARY FIX. I AM LOOKING INTO GETTING A REAL MOUNTABLE BUS THAT WILL MAKE THIS SAFER. But, for now, I used a rubberized wire mount so it wonít bounce around. I then found a small rubber grommet in the fire wall just located behind the gas pedal. I popped the positive wire though that and into the car.

     Pidster has installed a West Marine mountable bus. He installed it as shown.

     As you can see in this picture, I have fully mounted the wire using the old filter box mount. It fits perfectly. As I said before, this is temporary. I am looking for a mountable terminal block to make this more OEMish. Not to mention safer and able to be disconnected easily if you need to work on something. You can also see the wire running back to the firewall.

     I donít have any pictures of running the wire through the car, because the battery died on the camera. But anyway, itís pretty straight forward and simple. After running the wire through the fire wall, lift up your carpeting, and run it along the lower part of your footwell towards the drivers door. Pop off the molding, and you should see another wire already there. Follow this one under all the molding and up until you reach the back seat. Now you can just slide the rest of the wire though the hole leading to the trunk. Try to stay far to one side. There is a small hole you can run it though so it goes to the far left of your trunk instead of coming out the larger hole. Put back the molding and you should now have no problem with it.

     Here is my battery box. Notice the mounting hardware at the bottom. It is very important that you get this in stainless steel. Any good boating supply store like West Marine (where I work) will have them. I am currently using a ratchet type strap like one used in beds of pickup trucks. The mount is probably in the sailing section. The other pieces are in hardware. I STRESS DO NOT USE THE PLASTIC PIECE OR THE SCREWS THAT COME WITH THE BATT BOX. THESE PLASTIC MOUNTS ARE MAINLY USED ON BOATS, NOT CARS. DO YOUR SELF A FAVOR AND JUST BUY THE EXTRA STUFF, IT COULD SAVE YOUR LIFE!

     Here you can see the setup of the mounts for the Battery box. Easy. I used two washers. More surface area means more of that pressure exerted on the metal is more spaced out. This means less likely the battery will rip the bolts out of the trunk bed, and fly at you if you hit something.

     After measuring for my battery box I began to drill my holes for the fittings. Look underneath the trunk to see exactly what you will be drilling into. You donít want to drill into the chassis. Your bit probably wonít make it through.

     My hardware is all set and ready to go. Put on the strap for the battery box, and its looking good!

     You can see here the hardware mounted to the underside of the trunk.

     Now does that look sexy or what!!

     We have to add a ground for our battery. I drilled another hole in the trunk, and using the left over hardware I created a ground point (seen in red). Connect your ground wire to this point, and the other end will go to your battery. Make sure you have a good connection to this point or you will have too much resistance. This will cause your car not to turn over when you turn the key. That wonít be good will it? (Tip: you can never have too many ground wires)

     You must now take the positive wire and wire the breaker in series with the battery. Cut your positive wire and cut away the insulator. Slide on the lug, and crimp it on to the end of the wire. Connect this end to the breaker. Mount the breaker, and create another crimped wire that will go between the breaker and the battery. The breaker is there so if your battery does short out somewhere after the breaker it will kill power from the battery. Try to put the breaker nice and close to the battery.

     Now that everything is all set and done, go ahead and close everything up. Really tighten up your battery strap and make sure everything is secure. Once all things are secure, test a couple elecrical things like the door lights and such. Turn the key half way to see if your HU turns on. If it does, you did good. Now for the final test, your engine. Turn your engine over. If it started right up like normal you did great. If it had trouble there are a couple things to check for:

     Now you have two options:
     1.) Put your air filter back on and show off your "non battery powered car."
     2.) Get that washer resevoire out of there, and think about installing a custom cold air intake!

Questions? Comments? Drop me a line at