Thinking of relocating CT9A battery to trunk, fabricating a box and rewiring?
 

So- for a while now I have been thinking of relocating my battery to the trunk. For years now I have had a small "mini" battery. The car rarely gets driven (a few hundred miles a year) and sits on a small battery tender nearly all the time (I call it "on life support"). I was only let down once with the small battery, but it was too low of a charge and would not start the car (I needed a jump start) I've seen some of the trunk-battery relocation kits and installs here, and I am planning on doing things slightly different and I wanted to get feedback from others as I have never done this before.

I was thinking of putting the battery between the 2 rear strut towers in the trunk. Right now I have one of those "strut braces" that goes from left rear to right rear. Most of the people mount the battery near the washer liquid reservoir from what I've seen. What I was thinking of, was to tig-weld a sort of mount system that utilize the existing mount points for the struts on top where the nuts go. I was thinking of using 1/8" thick aluminum to make a bracket that spans between the struts and will hold the battery box in the middle. This way I don't have to drill into the car for the mounts. (I wanted to utilize some of the OEM hardware) I understand that I will need to put a breather hose on there to vent hydrogen created when the battery is charged- I was hoping to find a rubber plug on the floor pan that I could put a hole in so I don't have to disturb the metal of the floor pan.

I was hoping that having the battery further forward will help keep the weight distribution more optimal. Also- it will have a little bit more 'cushion room' if there is ever a rear impact. My other fear is that it needs to be a very strong mount- batteries are heavy and will have a good bit of momentum if the car is at speed.

So...what are you asking? If it's a good plan? If it's feasible?

sharing thoughts and looking for feedback

I`ve done it. I run a small battery in the truck and ran 1/0 all the way to the front of the car. It will actually fit under the plastic door sills with a light amount of trimming.

I have seen a few people place the battery where you are thinking to place it. I am actually taking on this project at the moment and am debating on putting it there or where everyone else does by the washer reservoir but i have the SSL with the subwoofer enclosure, so i am even thinking of removing the subwoofer and putting the battery in there...

Look up everyday metal design on Instagram, there is a bracket being made to utilize an evo x fusible link under the hood to clean up the relocation.
I've relocated my battery to the rear. We made a custom box and mounted it on the driver's side behind the wheel (also on that Instagram page). I would recommend an optima battery, or similar, instead of a lead acid battery if doing the swap. It gets rid of the need to vent.

I've had my battery in my trunk since 07 I use a fused distribution block (mini ANL) under the hood it's cleaner then stock and can simply change the fuses if it ever happens to blow...also rather then an inline fuse back with the battery I use a circuit breaker makes it easy to cut power to the car if needed.

Yea i got my bracket from them.

exactly how i did it as well. I prefer the look of the fused distribution block.

I looked at this closer last night and I saw that there are 2 threaded holes hidden under taped-on plugs. There is on on each side, close to the tail lights. I removed the tape enough to shine a flashlight through it and yes- it goes all the way out of the vehicle. I can only assume these are for mounting some component that my car does not have- and therefore are plugged off with these tape black circles. I am thinking it might be a good idea to use these for feeding out the breather hose. That way I don't have to do any cutting. I am not by the car right now so I can't take pictures.

Ive had my battery in my trunk for years with no problems. I used this kit https://www.summitracing.com/parts/tay-48103/overview/ but i recommend getting better terminal connections as the ones provided suck.

Hey thanks. I was actually looking at this one: https://www.summitracing.com/parts/s...31-k/overview/

The reason was I thought a plastic box would be best. I wanted the box sealed. I figured a plastic box would be less likely of allowing the terminals to touch metal and short together. I am thinking 1 gauge would be the right gauge wire for me. I do not have a stereo at all in the car but I do have some gauges and lights.

As far as research, I was reading this thread today. https://www.evolutionm.net/forums/04...ion-trunk.html
It appears to be for a "rallyart" but electrically, that should be very similar to the Evo 9 right?

I want to go to the metal fabrication store to buy my aluminum to build the bracket (that goes between the rear strut towers to hold the box) in a few days.

I am concerned with the 1 gauge routing backwards, and the venting mostly.

Do other members think that this ( https://shop.odysseybattery.com/p/pc1200 ) battery is too much for the car?

I would probably recommend the Taylor battery relocation kit. Not worth spending time to fabricate a box.

https://image.ibb.co/g5kQ8z/2006_mit..._mr_te37sl.jpg

I did end up going with the taylor box, but after I received it I have to say I am dissapointed with what you get for the cost. The kit is decent, just way over priced. I think I could have made it myself, learned more and saved money (not time).

That being said- I absolutely did not want to drill through my floor pan to mount the box. I am going to use the 2 little threaded boss-nuts on the bracket to the right hand side to mount the battery. I will also be modifying the back of the seat support to fit a much bigger bracket that will be most of the support.
Being that I am learning tig welding- I wanted to make this out of aluminum. I bought some 1/8" L-channel stock. 2 inches wide.

https://cimg4.ibsrv.net/gimg/www.evo...4c89d0d2f6.jpg

I cut the L-stock at 45 degrees (is this called a Miter cut?)

https://cimg0.ibsrv.net/gimg/www.evo...c90d3b3e17.jpg

I measured carefully, and cut the edges at 45 degrees each.

https://cimg1.ibsrv.net/gimg/www.evo...c731e0aa41.jpg

Next - a couple of small tacks just to hold it in place. With aluminum I like to use filler metal when making tacks- if you don't when it cools off it tends to crack (this is unlike stainless steel)

https://cimg4.ibsrv.net/gimg/www.evo...abfa7121ca.jpg

When i flushed up the surfaces it sat good on one side but the other needed some clamping to get it to be right and tight. Trying to weld something with a gap is much harder so I wanted to make sure I could get it to fit as tight as possible.

https://cimg7.ibsrv.net/gimg/www.evo...009a10e84e.jpg

Next after everything is good and tacked I checked the fit. It fit good, so I put some beads on the inside to make it stronger. It's hard to get the torch into the corner because you can't fit the filler metal in, so I only did about half of the inside. I am doing the outside as well as the bottom so it won't matter.

https://cimg0.ibsrv.net/gimg/www.evo...fe4235c34c.jpg

close-up of the weld (I am improving) 1/8" is so much easier than 1/16" thickness

https://cimg3.ibsrv.net/gimg/www.evo...db88fc41a3.jpg

Here you can see I did the bottom, this is where most of the strength is
https://cimg9.ibsrv.net/gimg/www.evo...abb8f14bb5.jpg

Now- I put it in the car, and it sits good but I want to put a few small feet on the edges so it sits better on the floor-pan. There are ridges and I've drawn spots where I can mount little feet. You can also see I put a piece of aluminum on the bracket on the right. I am going to build a bridge and mount the 2 together. The threads on the boss-nuts are m6x1.0

https://cimg2.ibsrv.net/gimg/www.evo...b703463d56.jpg
https://cimg1.ibsrv.net/gimg/www.evo...6956e2fbbb.jpg