4 guage ok for battery relocation?

i dont know if the reading you did was from one of JRickers (i can never get his name right) posts, but he is extremely detailed on how to run the wires to make it work correctly. You can shortcut it, but im using his method, and tweaking it a little bit since im running a 1 wire alternator.

and FWIW, its cheaper if you go to a welding supply store and get the cable from there. Make sure the battery box you use is NHRA approved. I bought the cheapie one from summit, then realized its not NHRA legal, andi had to go and buy a sealed battery box instead.

this is how my car is set up:
battery is in stock location

4 gauge from alt to 150 amp c.b. (+)
4 gauge from c.b. to battery (+)
4 gauge from battery to solenoid (+)
4 gauge from battery to chassis (-)
2 gauge from battery to engine (-)

my reasoning behind the 2 gauge ground is that the starter and alternator each have their own 4 gauge power lead, but share the same ground cable. it is unlikely they will be operating at the same time but it makes more sense to me to wire it this way.

the starter can take up to 220 amps so IMHO youre better off with the 300 amp c.b.
since youre putting your battery in the trunk, you should definitely use at least 2 gauge for the positive cable. for the ground...you COULD use 4 gauge but why? youre already buying a lot of larger wire. it will only be as strong as its weakest link, so use 2 or larger for both cables.

ttt

b] Rear mounted battery ground wiring. Follow this plan and you will have zero
ground problems.[/b]

One 1 gauge or 1/0 gauge wire from battery negative post to a clean shiny spot
on the chassis near the battery. Use a 5/16” bolt and bolt it down to make the
rear ground. Use a 1 gauge or 1/0 gauge wire from the rear ground bolt to a clean
shiny spot on the block.

One 4 gauge wire from the block where you connected the battery ground wire to
the chassis ground where the battery was mounted up front. Use a 5/16” bolt
and bolt down the 4 gauge engine to chassis ground, make sure that it the metal
around the bolt is clean & shiny. This is the alternator power ground.

The computer has a dedicated power ground wire with a cylindrical quick connect
(about 2 ½”long by 1” diameter. It comes out of the wiring harness near the
ignition coil & starter solenoid (or relay). Be sure to bolt it to the chassis ground
in the same place as you bolted the alternator power ground. This is an
absolute don’t overlook it item for EFI cars

Picture courtesy timewarped1972

Crimp or even better, solder the lugs on the all the wire. The local auto stereo
shop will have them if the auto parts store doesn't. Use some heat shrink tubing
to cover the lugs and make things look nice.

For a battery cut off switch, see
http://www.moroso.com/catalog/categorydisplay.asp?catcode=42225 is the switch
http://www.moroso.com/catalog/images/74102_inst.pdf
Use the super duty switch and the following tech note to wire it and you
will be good to go.

Use the Moroso plan for the alternator wiring and you risk a fire.
The 10 gauge wire they recommend is even less adequate that
the stock Mustang wiring.

There is a solution, but it will require about 40' of 18 gauge green wire.

Wire the battery to the two 1/4" posts as shown in the diagram.

The alternator requires a different approach. On the small alternator plug
there is a green wire. On the diagram it is #904, lt green/red wire that connects
to the alternator and dash light. It is the sense lead that turns the regulator on
when the ignition switch is in the run position. Cut the green wire and solder the
40' of green wire between the two pieces. Use some heat shrink to cover the
splices. See http://fordfuelinjection.com/?p=7 for some excellent
help on soldering & using heat shrink tubing.

Run the green wire back to the Moroso switch and cut off the excess wire.
Try to run the green wire inside the car and protect it from getting cut or
chaffed. Crimp a 18 gauge ring terminal (red is 18 gauge color code for the crimp
on terminals) on each wire. Bolt one ring terminal to each of the 3/16" studs.
Do not add the jumper between the 1/4" stud and the 3/16" stud as shown it the
Moroso diagram.

How it works:
The green/red wire is the ignition on sense feed to the regulator. It supplies
power to the regulator when the ignition switch is in the run position. Turn
the Moroso switch to off, and the sense voltage goes away, the voltage
regulator shuts off and the alternator quits making power.



See the following website for some help from Tmoss (diagram designer) &
Stang&2Birds (website host) for help on 88-90 wiring and lots more…

http://www.veryuseful.com/mustang/tech/engine/images/IgnitionSwitchWiring.gif

http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif

http://www.veryuseful.com/mustang/tech/engine/images/88-91eecPinout.gif

Diagram courtesy of Tmoss and Stang&2birds.

I run that very circuit breaker and like it a lot. It has a "trip" feature that allows you to remove battery power without messing with the battery posts.