2 Trunk Mounted Battery questions

[timmycharger]

I am putting the battery back in the trunk, which is how I had it prior to the resto, with a shut off switch on the tail panel.  The first time, I used a kit from Summit, which was 2 gauge or bigger, I dont remember.  Somewhere over the last 10 years I gave away the positive wire I had running to the front of the car, so I had to re purchase. I ended up buying 2 ga welding cable instead. Really nice wire, with the terminals already on them.  The wire looks physically smaller to me than what I had before, but my first question is will I be ok with this? I have read many conflicting things in my research but decided on the welding cable. Now that it came in yesterday, it looks skinny to me. 

Second question is in regards to how to wire it so that it shuts the car off when you switch the on/off switch on the tail panel. I know I had it wired this way 12 years ago when I last raced it as it wouldnt have passed tech inspection.   I have zero memory of how I had it before and of course didnt take good pictures back then when I installed it.  I do remember that I had a short battery cable from the battery to the switch, then the long run from the switch through the car and thats where I get hazy... I am running the mod outlined by Nacho, running the new black/red wires onto the ammeter, powering everything off the black wire side. Not sure if that makes any difference. 

I cannot wait for the electrical part of this resto to be done, its my cryptonite right now. Give me body work anyday of the week :0

[Pete in NH]

Hi,

Well, sometimes you could say not all wire is created equally. Good welding copper welding cable is getting a bit pricey because of the copper content  and price of copper. Sometimes you see "lower price" cable that isn't quite the gauge size it's supposed to be. You should be able to find out the true wire diameter for #2 cable by doing an internet search and then measuring the diameter of the cable you have. Measure the actual copper diameter as the outer insulation jacket thickness can vary.

On the wiring up of the system. Run the positive battery cable from the battery to your switch as you mentioned. Then run the cable from the other side of the shutoff switch under the car to the starter battery connection stud. Then there should be a piece of #8 wire run from this point up to the battery stud connection on the starter relay. That should power the rest of the car.  I would fuse that line with something like a 50 amp Maxi-fuse. You can find Maxi-Fuses and holders at your local NAPA store.

I would run the negative side of the battery up to one of the starter mounting bolts with another piece of #2 cable. When you run both battery lines to the front of the car make sure they are clamped down well at frequent intervals and placed where they will be as protected from possible damage as possible.

[timmycharger]

Thanks Pete, that is very helpful.  Ya, the wire certainly wasnt cheap, Ill do further research as you suggest.  I thought I would need to run a wire to the alternator to shut it all off from the switch on the tail panel.  I have no memory of how I had it before, its been apart so long!