Questions about battery relocation

[team39763]

I finally relocated my battery and added a cutoff switch.

Can ya'll explain some things to me. Why and where do I need an inline fuse? From what I've been reading, it says within 12inches from the battery terminal.  But before I moved the battery, I would just unplug my battery at night and connect it on days that I drive it. It didn't have a fuse back then, what's the difference now?
What about this alternator thing? My alternator is connected by the factory wiring going to the starter solenoid. Do I need to pull that harness apart and single out the alt wire and run it to the cutoff switch? My positive battery cable runs directly to the starter solenoid. I don't know if that's how things should be, but that's how my truck's been running for the last year.

[VileZambonie]

You're running a long unprotected cable through your body/chasis and need to install circuit protection. The closer to the battery the better. That's all you have to do.

[team39763]

Ok.  I'll order that inline fuse ASAP.

[JJSZABO]

I used a 50 Amp Maxi fuse.  I bought the maxi fuse holder at PepBoys.

[team39763]

I was reading and a few other guys used 200 amp fuse.  Does it make a difference?

[HAULIN IT]

Team, There are a couple things you need to be aware of. Per the IHRA/NHRA rules "The master cut-off switch must SHUT THE VEHICLE OFF when turned to the off position & must be clearly marked as such". The way you have it now, the alternator will keep the truck running. You need to run a wire back to either the + side of the battery or the battery side of the kill switch. I prefer to install a Ford type solenoid (some tractors/equipment have some similar or Painless has one too) near the battery, this leaves only a foot or so of live big wire. The rest to the front will only be live while cranking. The wire from the alternator should be fused/circut breaker, the current will flow both ways technically (from the alternator when the engine is running, but from the battery when it's not), so where to put the fuse/breaker is a toss up. Hope this helps, Lorne 

[VileZambonie]

Your starter can pull well over 200 amps of current so if you don't want to be changing fuses like crazy make sure if you're going to install an inline fuse to use a 300 amp breaker. Do you need a kill switch that will kill the engine? If so there are several ways you can wire it up.

[HAULIN IT]

Yes Vile, The rule states "Anytime the battery is relocated, a kill switch must be added to SHUT THE ENGINE OFF & ALL electrical power to the car from the rear of the car able to be clearly seen by track personnel".
 This is one of the rules that has some gray things about it. A guy can drive up in a car that came with the battery in the trunk or worse, under the back seat & race without the kill switch & go real fast (something like 9.50) as long as he didn't move it. Move the battery to the trunk or the bed in our case, do a first class install (rubber hose protection, insulated clamps, ect.) & now you need a kill switch regardless of the speed. Especially with a truck, this seems kinda wrong to me. The battery is safer in the back & getting to it in a wreck would most likely prove to be easier than under the hood, but they make the rules. Lorne

[VileZambonie]

He never stated if he was relocating it for track rules or not.

[team39763]

Yeah, it's for track rules.
  Hey what's the minimum thickness I can run for the ALT wire to the cutoff switch?  I can't afford to go buy 16ft more of 2ga.  stock appears to be slightly bigger than 12ga.  It's going to be about 16ft long too.

[JJSZABO]

He never stated if he was relocating it for track rules or not.

+1   I wasn't aware either.

My 50 amp maxi fuse is NOT in the red connection to the starter.  It is in the main line powering the fuse panel.

This is my write up on the way mine is wired - I used a Pineless wiring harness:

http://forum.73-87chevytrucks.com/smforum/index.php?topic=7173.0

[team39763]

Ok so what I'm looking at so far is:  Add 300amp fuse in between battery and cutoff switch.  Run Alternator wire all the way back to battery side of cutoff switch.  That should get me NHRA legal. 
Thanks for the link JJSZABO.

Another question - Will I be Ok using 8AWG wire to run from the ALT to the cutoff switch 16ft away? 

EDIT: I just thought about it...can't I just wire my ignition controller to the cutoff switch.  If I have no ignition, the motor won't run and the alternator can't charge.  That would save me from having to run more heavy wire through the truck(found out 8ga won't work for ALT)...Right?  My MSD box only requires 12v connection so I could just run that 8Ga wire back to the switch and be fine...Right?

EDIT AGAIN: Nevermind, I realized that won't work either.

[HAULIN IT]

Team, The 8ga. from the alternator to the cutoff switch should be fine, you defiantly don't need 2ga for that part of it. I see your edit, yes, your correct in that it still wouldn't shut off. It is still the same problem, the alternator would still feed the MSD box even with the cutoff switch off. The alternator separated from the ignition by the master switch is what you need to end up with. As I mentioned, I just don't like the idea of 16'-18' of unprotected 2ga wire, the 8ga is much easier/cheaper to protect & having a few spares isn't such a big (costly) deal.   
 While we are on the subject... What do you have for a hold-down on the battery? There are a few rules there as well. May as well get it right the first time. Lorne 

[team39763]

I'm working on building something from the stock battery tray and some long aluminum straps(that used to hold down my fuel cell).  But it has to be anchored to the frame right?  As far as I know, we don't need a sealed battery box since we have the bulkhead and cab between driver and battery.  I don't know exactly what I'm going to do yet though.  What would you suggest?

[HAULIN IT]

Team, You are correct, you do not need a box. The rule reads similar to this: The battery must be held in with (2) 3/8" bolts/rods, J-hooks must be closed & welded shut. Some type of metal retainer must secure the battery & be mounted to the frame/frame type structure. This leaves quite a bit to the interpretation of the tech at the track. Anything able to carry the weight & not tear-out if force was applied would seem to count as a frame structure (bedfloor braces, angle iron, square tubing of reasonable thickness across a span all seem to be adequate. You see those 1" or so tubing ones hanging to the outside of the frame on many cars, this all seems to be acceptable. Have Fun, Lorne