Moving the Battery to the back of the car. - Third Generation F-Body Message Boards

Demon_Eater · 10-09-2009, 12:02 AM

I have a question, I decided I wanted to move my battery to the back of the car like I read on the article of shedding pounds. I have a battery box for it and Im going to use my amp wire (its big enough wire and just needs to be hooked up to the alternator.)

Anyway, I read a warning label on the box that it needs to be well ventilated, and batteries will cause harmful gases and keep away from any spark, cigarettes, etc.

My question how dangerous would it be if I had the battery down in the well area? (idk what else its called, the very back of the car) My amp sits down there right now, and I may have to move it up if I have to, and probably will) and its under a board that where my subs were at and black carpet covers the whole back of the car so its all smooth from where the back of the back seats start to the back of the car.

I just want to know any tips I should know if I do this, because I dont want this cost my life later down the road if something spark like with anything (turning on my cd player, or anything sparking).

Thanks,

Tim

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Stephen 87 IROC · 10-09-2009, 01:50 AM

A number of things first.

Why do you need to relocate the battery?
If it's because you want to move weight to the rear for drag racing then there's a bunch of other issues that need to be addressed with the battery relocation.

I doubt your "amp cable" is suitable enough for starter draw to start the engine.

Now if you decide to do to a dragstrip, a relocated battery needs a bunch of things. You say you already have a proper battery box. There's only 2 that I can think of that will pass a tech inspection. The big blue plastic one from Moroso and an aluminum one from Taylor. These are the only ones that are acceptable if the battery is located in the driver's compartment which includes all third gens. These boxes are considered a sealed design that have a vent tube routed to outside the vehicle. If a rear firewall was fabricated, the battery could sit in the open or inside a marine battery box. Putting the battery inside one of the rear compartments isn't acceptable to pass tech. The safest battery to use is a gel type battery such as an Optima. They can be mounted in any position and even if you try to cut one open with an axe, nothing will leak out. Even a battery like that needs to be inside a sealed box as per NHRA/IHRA rules.

Once you move the battery to anywhere other than the stock location, a master switch needs to be installed at the rear. The master switch is wired into the positive cable and must be wired so that when the switch is turned off, it will kill all the power to the car and also kill the engine. An alternator will backfeed and keep the ignition working so the wiring needs to also kill that circuit.

As for the switch, there are a number of locations at the rear it can be mounted. On a car that sees regular street use, it can be mounted inside the car with a removable shaft so that nobody can kill the power as you use the car on the streets. The switch can't be keyed or made of plastic. Off must be clearly marked and if installed as a push/pull, push is off.

oil pan 4 · 10-09-2009, 03:49 PM

I was planing to mount the battery in the back of my car, but after I got hit in the *** by a drunk driver while driving around with a friend in their car it doesn't seem like such a good idea.
Summit offers a "sealed and vented" battery box now for cheap. $70 is cheap compered to the Taylor and Moroso boxes.
As a compromise I was going to put my battery under one of the back seats or maybe just turn the seat into some kind of battery box cover. Since I have only had to use the back seats a hand full of times in the last 7 years to move people.
Now no matter where you put it when you make the distance further than the stock location you will want to use at least 1ga cable.
I have a roll of 00 gauge cable I use for all my battery cable projects. I recabled my 6.2L diesel suburban with 00 gauge it cranked over a whole lot faster, the stock cable was about 4ga.

five7kid · 10-09-2009, 05:01 PM

A seat isn't a sufficient "wall". It has to be metal and seal off the area the battery is in from the passenger compartment.

Or, use a sealed battery box. I got the Summit sealed box for the '57 this spring (because the '57 trunk is only separated from the passenger compartment by cardboard and the rear seat back).

oil pan 4 · 10-10-2009, 09:54 AM

Yeah a seat as a battery cover is bad idea. I would only use a sealed vented box if I were going to mout it in side the cab. I know some people don't but that is all on them.

Demon_Eater · 10-11-2009, 02:47 AM

Mkay,

I already knew this was going to be a concern from the first place when I was thinking about moving the battery to the back of the car. and besides I don't exactly know where a great spot would be to put the battery box in my car since I don't want the back to be seen in the back of the car, I just have two sub boxes shown right behind the back seats and the amp is under the sub plate I made that sat over the welling area and carpet covers the whole back of the car so it kinda looks all smooth in the back. most people wouldn't even know there was something under the carpet.

Anyway,

I understand "amp cable" wasnt exactly a good referance to call the wire, it is a heavy wire (I believe its a 12 gauge? not sure... but its a way bigger cable than my postive cable wire for the battery.) I guess I could go buy the jell battery but I didnt really want to go for another battery because I just bought this one to replace my old one. and I already bought a battery box (yes, dumb idea, kinda jumped the gun) its a marine battery box so I might not even use it.

I wasn't exactly planning on going by NHRA rules, but I guess its better I read and go by them anyway.

My plans for this car still drives the street, but I dont drive it anymore since Im paying for a truck. my friend and me wanted to take our cars down to a drag strip, I dont know much about it, but all my friend tells me is that you can bring whatever vehichle you want and race it. I figure I'd do some things to my car to improve it a little better with the inexpensive things first before I start piling money back into it again.

8t2 z-chev · 10-11-2009, 12:57 PM

I relocated the batt in my car to the spare tire well-
welded up a battery tray with a clamp to hold the batt.
ran the cable(not sure of gauge,its pretty stout) up over
the rear fender well,under the door sill trim(just barely
fit under),through a hole under the heater box(where
my amp power feeds used to run),to the starter motor
Batt is grounded in the rear,while a short piece of the
same battery cable was mounted between the engine
mount and the crossmember to properly ground the
engine. Did this to gain room for an air compressor +
tank for twin trumpet hadley truck air horn

no
problems at all with the batt relocate, and i expect
the batt to last longer back there