Spent a good part of the day relocating the battery to the rear of the car, in order to reduce some of the weight in front of the front axle.

You can do this project by putting together your own parts, or buying a kit. The kits usually go from $75 and can go up to $175 for the fancy aluminum boxed kits.

Let's start with the wiring. You need to run a positive wire from the front of the car to the back. We used a 1-gauge wire here. Ran it through the firewall, along the driver sides sills to the rear.



I decided to mount the battery on the drivers side rear, in order to retain most of the factory features (spare/dvd drive). The battery I got weighed in just under 40lbs, not much different from the factory battery. This may not seem a lot, but because the stock location of the battery is quiet far in front of the front axle, it acts as a fulcrum multiplying the actual weight.


Removed the trim to find the drill hole points for the mounts.


Place the securing bracket to determine the drill points and mark them.



On the bottom of the car, you need to remove your rear muffler, and the heat dissipation shield (four 10mm bolts). Make sure you don't drill in the "support" beam that runs on the bottom of the car.






The battery will go into the provided enclosure. Drill holes that will match the offset of the securing bracket.



Install the mounting rods with a washer, and make sure it fits with the battery box in place.




Heat shrink all your connection points. Sand down the paint on the chassis to ensure a proper ground, and connect ground.




Find a venting port, and run a fume exhaust tube to it for the battery to vent.


Put battery back, tighten securing bracket to the posts, and you have yourself a bit less weight up front.



Install took around 4 hours, but you can knock it out in 2 hours if you have a few red bulls before starting.

 

A+ For the write-up
A+ For the pics
D- For the Kragen/Duralast battery =p

 

I hope you DON'T get into an accident, where that side of the car gets a hard imapct. Also when the battery vents, it's going inside the cabin. I think a gel-cell (Optima) battery would be a "safer" choice. Just my ...

 

I would say go with the light weight Braile battery!! A gel cell or a non liquid filled battery.

But great write up and picture details.

 

Why would the battery vent into the cabin?

 

^ guess they missed it

 

Nice writeup!

..your front to rear ratio should be a little better now. Plus you've now got the room in the engine bay for that turbo! haha

 

Black is right! I just wouldn't trust an acid battery in the trunk of my TL. But, to each their own..

 

Oh shit didnt even think of that haha


Aznbo..great write up man Im actually surprised, especcially lookin at the pics, that it took you four hours, thought it would take you more.

 

turbo shmurbo... it takes aznbo forever to do everthing, damn perfectionist... how long does it take aznbo to rotate his tires... 5mins a lug (OCD I tell yah) much love

 

i would love to this, but im guessing a lightweight battery....

 

The car actually feels quiet different now. The nose goes into direction much easier, without hesitation. Although not a huge difference, it's there.

As far as the battery itself, I hope I don't get hit on the right rear. I just bought this battery new so I'll just replace it when time comes.

 

so whats the weight difference between the stock battery?

 

And my battery? Probably about 2lb's if that...

 

So it looks like I just worry about the first point in the fuse box to run the red wire to, and not to worry about messing with the second wire that runs to the starter?

 

Nice use of an existing thread. The positive cable from the battery goes to both the underhood fuse/relay box and to the starter. So you have to make sure both are still connected.

 

where the hell in the firewall can you pass the wire through??? im stuck. gonna drill

 

This was such a long time ago I don't remember..It's the same path people route the power wire through when installing aftermarket stereo systems. Do a search for that you should be able to find it in electronics/audio.

 

I already have a 2AWG running to my trunk for the stereo install. would it be wise to put the battery in the trunk even thoe i have the one 12" sub in a sealed enclosure with two small lightweight alpine pdx amps

 

nice write up.

 

found it in the middle of the firewall...all done
now to get the old battery out from under the supercharger!!!??!

 

If you are not into racing your car the relocation of the battery from front to back is not a noticable one. also you need to vent that battery. check with your insurance company but they might refuse you if it was not done properly. the battery can cause a fire harzard within the passenger compartment.

 

^^^^^

 

good write up man thanks

 

Yo cool write up..what would be the most recomended light weight battery?..Regular batterys are super heavy saveing some weight would be nice.But do they would have any downsides compared to an average bat?

 

Yes lightweight battery's are less powerful. The weight savings is not worth the extra cost and smaller power reserves. Some have had luck with Braille battery's.