I just wanted to ask for a little help figuring out how to wire up a battery cut off solenoid or switch.I have a basic concept of how it would need to get wired and here are two pics my only question is the second post on the fusebox labeled ALT would it be left open after wiring the alternator dorectly to the battery?The solenoid setup has 4 posts two large and two smaller posts.The large posts are for ground and 12v conctant and the smaller posts are also a 12v and a ground were the on off switch is wired in.I am only asking because NHRA rrequires me to install one on my car and I just wanted to make sure I understand what needs to be done.

 

Here is a picture of the solenoid

 

The two big posts are the switch, in and out.

The small posts are either power and ground, [solenoid switch control] or one is a 12V+ input, [switch control] and the other is 12V+ output when solenoid is energized, depending on what kind of solenoid it is.

For a batt. cut off you need a constant duty solenoid, for NHRA all power from batt. must be cut along with the ign...

Connect the batt. cable and the alt. cable to one of the big terminals of the solenoid, run a lead from the other big terminal of the solenoid to where batt. cable was connected to fuse box. 94

 

Ok Thanks again FCM I was hoping you would chime in.I guess the alt side of the fuse box stays open then?Thanks again

 

NRHA requires all power is cut, that includes the ign., if you cut just the batt. the alt would keep the engine running.

You can also run the alt. lead to the batt. like you suggested ot to the batt. terminal on the starter motor, as long as no power gets to the engine bay fuse box when batt. switch is off.

You are not relocating the batt. are you? 94

 

Yes the battery is being relocated to the front fender location behind the bumper.I will probably mount the solenoid in the passenger side kick panel and run the wiring for the switch up the passenger side to the rear tail light where the on/off switch will be mounted or maybe the keyhole.

 

Tony I was looking at our wiring diagram and there should be two black wires: 1 going from the battery to the fuse box and the other to the starter. Tie in these wires with the solenoid so all power is cut like a master fuse.

I hope I made sense.

 

Yeah you both were helpfull.I pretty much have it all straightened out now.I just need to weld in the battery box in the fender and wait for the solenoid to come in so I can wire everything up.I was told that the solenoid should be as close to the battery as possible but I am planning on putting it inside the car.I dont think 4 feet of wire between the battery and solenoid will make much difference.

 

Well it's like an in-line fuse when you install an amp in the back, you want that line of power cut as close to the source as possible when something shorts or when you need power cutoff. That is why the fuse box is located as close as it is.

I don't think it'll hurt to have it in the pass. kickpanel, but if you could move it closer to the battery then great.