View Full Version : How to: Rear battery relocation (56k warning)

02-26-2005, 02:26 AM
heys - as promised - this is a quick no bullshit way of mounting the battery in the boot of a gt4 :

The basics of what youll need :

* Small sealed battery - Oddessy or similar ( i used a 12v800 unit)

* 1 battery box - Ill Leave this one to you to size up

* About 7 ish meters of welding cable - or very VERy heavy guage battery cable ( i used cigweld double insulated welding cable - its pretty blue , flexible , fine stranded , and cabable of holding 400 amps - tonnes for this job

* Lugs to suit your cable - so you can bolt it onto stuff - Asuto shops have these - solder or crimp on

* A roll of electrical tape

* battery terminal thingies - get one with an isolator - its handy!

* a length of pipe insulation , the stuiff they use on water pipe

* wire covers - that wrinknly stuff , thats split down the middle to cover wires in mass.

* Some sort of bolt down brace to mount battery into the battery box - i used 2 x 3/8 bolts , about 5 inches ling , with wingnuts , clamping down a piece of plate metal over the top of the battery

Ok - youll probably need other crud - but that should get you started !

Now the fun ..

02-26-2005, 02:28 AM
Now the fun!

Im not gunna tell you how to do the next step in detail - but it revolves around removing ALL the paneling along the passenger side of the GT4 , from back to kickpanel ..Take out the rear seat and the passenger seat too - it will make your life alot easier - trust me!

Its pretty easy - just time consuming ..

You should be able to remove most of it in an hour or so - panels , seats , the lot

Also - remove the passenger front wheel - and take off the splashguard thats under the arch - this is a bit of a prick to do - but be patient with it and dont yank it ! they are expensive to replace ! This will expose the easiest past of the new cables path !

Now - in the engine bay - remove your battery - as it no longer has a home in the bay , AFM , airbox - and that annoying duct that runs up behind the light - this ones also a prick to remove - be gentle - take your time - and lever it out - you dont want to bust your aircon lines!

this will free up the space you need to start cleaning up the wiring that went from the battery !

First - the positive side

there is 2 cables that run off the battery positive ( 3 if you have an amplifier - but thats another story ) One goes direct from the battery to the starter motor - the other goes from the battery to one of the fuseboxes !

What we need to do - is take the coverings off these wires so we can split them up - be careful - remove any elec. tape or crinkly loom wire covery things so you have access to both wires!

once split youll clearly see which is which . We need to retain the one going toward the firewall ( thats the fusebox one ) Instead of going to the battery - reroute it so it connects up to the starter motor - ( see upcoming pics! )
the other one that goes to the old battery terminal - chuck it - no longer needed - its job will be replaced by our new fancy cable! .. ( pic to come )

The negative side !

this ones pretty easy - negative runs from the battery to the top of your gearbox - once again - follow the cable down - and unhook it - its a direct path . We'll do this cable first as its straight forward - Find a decent earthing point on the body ( i chose a bolt that holds a small bracket ( holds loom in place )on the strut tower , cleaned the paint off surrounding it , Did the same with the bracket - + prepared it to earth ..

I cut about 30 CM of welding cable - Crimped on 2 lugs - and bolted it back up - Simple! Done ! Tis is the first earth strap - the other will go in the hatch near the battery !


having prepared the path - i moved onto laying the cable down!

This takes up the majority of the cable you purchased - youll need to run it along a path similar to this ( this is my suggestion - if you find a better way - by all means - use it !)

This is how my cable runs - from back to kick panel!

from the boot


passenger seat

Under the kickpanel ( see small grommet above fusebox )

Thru under the arch ( use the really handy factory clips to run it to a small grommet where the other loom you follow comes thru!! VERY HANDY TOYOTA! )

thru into the engine!
Cover this section with the insulating foam too - for some protection from engine bay heat + things rubbing it )

Connecting to the starter motor! Path complete!


Your setup should look something like this! its the most logical way ive found - after trying a few different paths!

At this stage your only measuring it up - Cut it off where you feel you have plenty of cable to hook up to the starter motor , and have plenty of play in the boot ..

When your happy that your positive is long enough - Crimp or solder 2 more lugs up - hook one to that bolt off your starter motor ( along with the other positive that runs to the fusebox ) , bolt up - And that ends done - Finito!!

The other end - Lug , solder/crimp in preperation to hook up your battery terminals

This should finish off all the wirey related work in the engine bay - If your happy with it all being safe , protected + secure -put back in your airbox + afm etc - brace your fusebox ( i used a temporoary bracket off the airbox - to hold fusebox ) , And your done for the front!!

02-26-2005, 02:31 AM
Now from here on in - we start tidying things up

If your happy with the path taken ( i was ) and happy with the engine bay being compete and up to scratch ( yup - happy with that too ), start working on getting it all sorted in the back ..

I started by setting up a secondary earth strap off the battery - grounding it to the other strut tower via one of the bolts on top .. Once again - clean back to metal for good contact , prep - and cut another suitable piece of cable - say 60 Cm this time .. Lug , solder and crimp the ends - and your second earth is complete! This one will run to the negative termninal on the battery !

After all the wriring in the back was ready , mine looked a lottle something like this ( minus terminal to hook to battery )

That red lead is my amp lead - ignore if you dont have an amp - take note , if you do!


You can see clearluy in this pic the floor of the hatch - Under that is your fuel tank - BIG BIG take notice!

When your readying to mount your battery box - use the shortest screws possible - you only have a maxumum of 15MM under this befoire you hit the fuel tank

My battery box came with a strap - and 2 saddles to hold the strap down - this is only to hold the BOX down - youll need to be crafty in mounting the battery itself in the box -

( for this i used the above 5 inch or so bolts , plate brace - with insulating over it and secured down with wingnuts - make sure you have good clearance for your terminals - remember - that metal brace wilkl conduct !!)

Back to the strap - I mounted one saddle right up against the white plastic thing you can see - using metal self tappers - and about 4 washers per screw - not to hit the fuel tank

the secondary - i mounted between the two grommets you see in the lower left corner - theres good metal there - pop them out and feel under - youll see what I mean

I havent got a pic of this - but can get it if asked nicely !

cut two small slits in your boot carpet to feed your strap thru - then start putting all your panels , seats , carpet etc etc back in bar for the rear most plastic panel - and back seat - leave them until your happy with how the cable feeds to the back.

Havent got a pic of this either - im working on it !


In this pic you can see my temporary solution to how to get the cables thru the last panel - i removed the small light in there ( its broken - needs repairs - fed the cable thru to the batterybox .. )

This is with the battery box in place - all hooked up - See my bracing ? See the isolator green thing - very handy!



And this - is the final product - all hooked up - and secure!


I have some fine tuning and neatening to do - but this setup works - ive tested it - and nothing caught fire!

So there you go - this is only a example of what can be done - I WONT BE HELD RESPONSIBLE FOR SOMEONE REPLCATING THIS AND BURING THEIR CAR DOWN.. ( standard disclaimer - use at own risk! )

02-26-2005, 08:42 AM
fantastic write up man, what did all that gear cost you if you dont mind my asking? the cable im guessing was the most expenisve

02-26-2005, 10:36 AM
rough breakdown of costs:

battery - $270

Box - $ 32.00

Cable ( for 7 meters ) - $42

Lugs - $2.50 each

Bolts nuts etc - Scavenged from work

terminals - recycled

All up - under $400 dollars all up - including the battery

02-26-2005, 02:58 PM
Where did u buy the battery box? Ive been looking for one, im sick of my battery where it is...


02-26-2005, 04:15 PM
man that fucking nice job there mate...i just replaced my battery cause it died...and i wanted to geta sealed one and shit...but for a good power rating like the one u got was more than $270..were did u get it..is it a 800CCA one???and also were would i get the welding calbe cause to go and get 7meters of 0 gauge speaker/battery cable would be liek 100 odd dollars...and that welding one sound god cause it thin wires in the core..i like!!!!!!

Good thread!!!

Nezza :wiggle:

02-27-2005, 02:30 AM
the battery box is an off the shelf item at autopro

the barrety was bought from a local battery supplier in ballarat - i believe it was R + J batteries - but not sure - as the mechanic got it for me ( so i might have got trade )

it is a 800 CA one but is only rated at 400 CCA

The cable i bought from an Ag supplier here in town - they deal with welding equipment - bought off a bloody big roll ..

jobs pretty easy - just time consuming .. the only hurdle i had was mounting the battery box - ie finding metal i could drill into without going thru the fuel tank as well

02-27-2005, 03:26 AM
thats a frigging expensive battery!

02-27-2005, 07:08 AM
yeah, you can get the battery boxes from repco/autopro, straight off the shelf.

hey classique, did you notice a difference in the cars handling and takeoff witht he battery in the back??just wondering becoz a mate and i swapped the battery to the boot in his ET turbo so we could do the AFM relocating/straight intake mod and he reckon he noticed a big difference in takeoff. More wheelspin! LOL

Nice writeup :)

02-27-2005, 07:31 AM
yup its an expensive battery but its only 70 mm long by about 70 mm high - about 2/3 if that of a standard battery but with more cranking power - worth every cent IMHO - plus you can mount it any way you like - on its side , upside down , in angles - you name it!

id reccomend to ANYONE serious about doing this to get one

As for the handling - no diea on that mate - it went straight back to the engineer as soon as it was running again - so i can get the st205 brakes engineered.. 25 KG really isnt going to make that much weight difference for wheelspin - i think your mates being abit optimistic

Ill see if it does make any difference as soon as its back motoring again - it needs the cobwebs blown out of it again ( ie a superfly great ocean road . otways fang )