Boosted Falcon

Battery to the boot relocation tutorial.

Shopping List:

Sealed battery with breather - $200 (required for ADR compliance and to avoid blowing yourself up with hydrogen gas from when charging)
Battery terminals -$10
Large battery box - $30 from Supercheap
Battery tray - $10 from Supercheap
Teks screws or M6 bolts- $10 from Bunnings
1m M8 Threaded Rod - $7.50 from Bunnings (for battery brace)
1m 1"x3mm Flatbar steel - $7.50 from Bunnings (for battery brace)
M8 nuts and washers - $2 from Bunnings (for battery brace)
6m red 0awg cable - $120 or $20/m from any auto electrical shop (try get the insulated and sheathed stuff - it's much tougher than that soft plastic clear sheathed only amplifier cable)
1m black 0awg cable - $20
3 0awg cable lugs w/ M10 centers - $15
Big battery block to take all wires - $35 from Autobarn
Restecp for not starting another "how do I relocate my battery to the boot?" thread - Priceless.

Install:

In my ED I mounted the battery box next to rear driver's side quarter panel (uses least amount of boot space there) and fastened it to the boot floor with 4 x teks screws. I then put the battery tray in the centre of battery box and fastened it down with another 4 screws. If you're feeling particularly enthused unlike myself you can always drill holes through the floor and bolt it on from underneath the car, but the 4 tek screws were enough to make it very sturdy.

For the battery brace I drilled 9mm holes above the top (front of car) and bottom (rear of car) ends of the battery tray through the battery box and boot floor. I cut the threaded rod into two pieces of suitable length for the height of battery, placed rod through holes and fasten in place with a nut, washer and loctite on both sides of the boot floor. When drilling the holes make sure you inspect from underneath the car where they go, otherwise they may end up in the chassis rail and you won't be able to get a nut on from underneath.

I cut the flat bar to suit distance between threaded rod and drilled holes at either end for the threaded rod to go through. Bolt the flat bar down over the battery on the threaded rod and it will not budge regardless of any awesome lateral Gs.

You will also need to drill a hole through the boot for the sealed battery breather tube. This will evacuate any hydrogen gas out of the boot made when charging the battery, thus avoiding a potential explosion.



Now for the wiring.

Run black 0awg cable from relocated negative battery terminal to one of the big bumper bar bolts or tow bar bolts if you have one (use 2 x cable lugs). Sand back the earthing point so it is nice shiny metal for the best connection. If you're paranoid about rust like me you can spray over it with a lick of paint once everything is bolted down. I drilled a hole through the side of the battery box at the very bottom for the cable to run through, under the boot carpet so it wasn't visible.

There are many ways to run and wire the positive cabling. I elected to run the red 0awg cable underneath the car directly to a distribution block where the battery used to be, and reconnected all the wires that used to connect to the positive terminal of the battery there. Another frequently used option is to run the positive cable from the relocated battery directly to the starter motor, then piggy back the existing starter motor cable from the starter positive terminal to the distribution block where the battery used to be, once again reconnecting all the wires that used to connected to the positive terminal of the battery there. Both work perfectly fine. In this tutorial I'll describe the first method that I selected.

Once you have worked out which way you would like to go, have a good think about where you want to run the cable and inspect the entire route before installing anything. I drilled a hole through the side of the battery box at the very bottom like the earth cable, ran under the boot carpet through to under the rear seat, then through the floor and under the car next to the chassis rail until around the B pillar, then into the chassis rails forwards from there to shield it from the heat off the exhaust, out of the chassis rails once inside the engine bay to its final destination.

Once you have terminated all positive wires that used to be connected to the positive battery terminal and (if you chose the same method I did) red 0wag cable onto the distribution block, connect all the negative wires that used to be connected to the battery to the existing earthing point on the chassis rails. Finally hook up your red 0wag cable to the relocated battery using the remaining cable lug. Turn on the ignition.

If everything lights up you're done. If it's on fire you probably should have taken it to an auto electrician.

love the last sentence

i just did this in the xr8

i found it easy to run the cable out under the the back seat. and then through a factory rubber plug into the side where a sideskirt would be fitted.
out of that near the front of the front door.

just less chance of damage going inside there. it is only visible under the car in 2 parts for maby 10centimers

+ 1 for the last line.

i just did this with the el too.

ran the power cable through the car, under the carpet. probably dangerous as hell. but it looks neat.

ran the cable in conduit and heat srinked both ends for added saftey.

positive from the batt to the starter then to a power block.

good write up donno.

I would add a fuse aswell... Dont wanna have and accident and the cable gets cut and your shorting to something, nice way to start a fire.

xgxr6 wrote:I would add a fuse aswell... Dont wanna have and accident and the cable gets cut and your shorting to something, nice way to start a fire.

You cant run a fuse mate, too much current on start up, fuse would blow everytime.

I always thought you were ment to run a fuse also? Big sucker of a fuse.

Will have to ask my mate what he done with his. I know he has a inline cut of switch so he can disconnect the battery, but not to sure if he has a fuse or not.

AdamF wrote:

xgxr6 wrote:I would add a fuse aswell... Dont wanna have and accident and the cable gets cut and your shorting to something, nice way to start a fire.

You cant run a fuse mate, too much current on start up, fuse would blow everytime.

I have a fuse and havent blown it.
If you dont put something then your an idiot.

I put a 200 amp fuse on mine and never had any issues, its only for shorts, because if u don't have a fuse and the cable is nicked you will have excess of 500 amps shorting resulting in a fire very quickly....

Yeah that's what I thought. Positive my mate has one. But would still have to confirm.

Fuse goes right at the battery side yeah?

The closer to the battery the safer

Moar pics! You guys are making my life easy. Gonna try it soon. Thanks

Here pic's
I got it from a profession sound system installer, for reference that's 00 cable running through it.

Look up auto speed there's a DIY thing on there. It shows the circuit breaker and goes through some capacity of different size cable

00 gauge was always the smallest I would run if I ever do it. But my cars are wagon's lol.

Mines a sedan and the cable takes a a few twists and turns .
You gotta remember that a falcon is about 5 meters long.
I'd say i have at least 6-7 meters of battery cable.

I have some pics in my build thread of my setup, I also have a few more if your interested.

viewtopic.php?f=3&t=20028

I was more referring to nowhere to really put mine being a wagon. No matter what I done it in I'd always use at least 00 gauge. Heard to many stories about poor cranking after moving the battery to the boot

I had that problem, I found it was due to a bad engine earth. I got a BA earth strap which is thicker and put it on an a/c compressor bolt and then onto the earth bolt near the thermo fan fuses. Starts perfectly fine now

Just put earths everywhere I've read an article in the last that suggested 3 earths of the battery as short as they can be straight to decent grounds. Also another was suggesting earthing battery as short as possible in the boot, and running another earth back to the original earth point.

Yeah I've got a couple earth straps in my boot really direct to my battery. They didn't really seem to do alot for cranking issues. Once I earthed the motor good it cranked over easy as. But yeah you can never have too many earth straps.

holmsy wrote:

AdamF wrote:

xgxr6 wrote:I would add a fuse aswell... Dont wanna have and accident and the cable gets cut and your shorting to something, nice way to start a fire.

You cant run a fuse mate, too much current on start up, fuse would blow everytime.

I have a fuse and havent blown it.
If you dont put something then your an idiot.

I have a cb, but it runs through the cabin and pops out straight onto the starter motor no chance of damage as there is double insulation/mechanical protection, wouldnt have thought a 200A fuse would have done the job, but if its working all good.

200amp is the lowest your can go. it's around 140amps for the starter and 60amps to run the engine/ecu during cranking.

Thinking about it again I think its a 250amp fuse I ended up going with

Yer the 200 is the bear minimum to use. if you have a flat battery or bad earth you'll probably pop it.

So would a 300 or 250 be the recommended size?

OMY-747 wrote:So would a 300 or 250 be the recommended size?

This would be the right idea, something that wont operate during normal operation of the electrical system.

i would definetly fuse a battery relocation

and yeah 200 to 250 would be pretty sweet for a standard starter motor

i have run 4 gauge wire from battery to engine bay but did notice voltage drops when cranking so i allways run 2 or 0 gauge now

good write up tho

does anyone know if this will be roadworthy?

looks secure, just need to fit and run the vent hose outside.

Something i yet to do 5 years after since fitting my battery in the boot

yeah im planning on using the factory wood cover which i will bolt down and will add a vent or two in the wheel well itself.
just wasnt sure if there was anything else that needed to be done for it to meet RWC requirements.