Wiring a kill switch

[johnkuhn]

I am going to install the kill switch per NHRA rules. The Fairlane has an alternator with an Internal voltage regulator and the car has an MSD box. What is the correct way to wire the switch? I have been told 4 different ways and need some help on what is correct.

John

[McCloud Motorsport]

I believe Moroso makes a kill switch with a set of alt. contacts in it now. I used a painless kit for mine. You need to run the charging wire from the alt. through a set of contacts that are normally open so when the kill switch is off they are open. Then power the solenoid from the switch(ed) side. Its very simple to do with any solenoid. Just got to make sure the contacts can carry the amps.

[Herb Hagan]

Here you go,

This is what I use at the back of the car

http://www.speedwaymotors.com/p/6967,247_Four-Post-Battery-Disconnect-Switch.html

This is what I use inside the car, next to shifter, so I can kill the power while strapped in my seat

http://www.flamingriver.com/index.cfm/page/ptype=product/product_id=64/category_id=133/home_id=76/mode=prod/prd64.htm

[85SALEEN]

I have a 1 wire alt. so I just ran a wire frome the alternator to the positive post of the battery.

[Herb Hagan]

I have a 1 wire alt. so I just ran a wire frome the alternator to the positive post of the battery.

I too run a 1 wire alternator

The problem with wiring your alternator to the battery w/o a kill switch is that you will still have a hot wire and post @ your alternator, which can be an ignition source (arc flash) if something was to loosen or be damaged during an "incident"...food for thought

[Richard Maitre]

Herb, how is the car coming? Will we see you bright and early this season? Possibly in another class? 

Rich

[Herb Hagan]

Herb, how is the car coming? Will we see you bright and early this season? Possibly in another class? 

Rich

Hey Rich!

I will be there running AMI, not sure about what index yet

[85SALEEN]

I have a 1 wire alt. so I just ran a wire frome the alternator to the positive post of the battery.

I too run a 1 wire alternator

The problem with wiring your alternator to the battery w/o a kill switch is that you will still have a hot wire and post @ your alternator, which can be an ignition source (arc flash) if something was to loosen or be damaged during an "incident"...food for thought

I have a kill switch. It was the only way I could run it with out problems I thought and still charge the battery.

[Herb Hagan]

I have a 1 wire alt. so I just ran a wire frome the alternator to the positive post of the battery.

I too run a 1 wire alternator

The problem with wiring your alternator to the battery w/o a kill switch is that you will still have a hot wire and post @ your alternator, which can be an ignition source (arc flash) if something was to loosen or be damaged during an "incident"...food for thought

I have a kill switch. It was the only way I could run it with out problems I thought and still charge the battery.

If you are running a 2 post kill switch, that is the way to wire it and still have it function "OFF" correctly, but you will still have a length of wire from the alternator to the battery that is still "HOT" with the kill switch "OFF"

That is why I posted the link to a 4 post kill switch, it will not have a live wire and alternator post when "OFF"  Your charge wire will run from the alternator to the separate kill switch contact points, then to the battery
The intent of the NHRA rule is to have the entire electrical system be "OFF" when the kill switch is activated.

I ran the 2 post kill switch for quite a while before I became concerned about this possible "Ignition source", but an incident @ 125MPH opened my eyes to the "What if" scenerio...like I said before "food for thought"

http://www.speedwaymotors.com/p/6967,247_Four-Post-Battery-Disconnect-Switch.html

[johnkuhn]

Thanks guys! I had bought a 2 post switch and am taking it back for a 4 post. It now makes sense as we had it figured that the alternator would keep the car going with the switch turned to off. It should be an easy install now. If it would only get warm and dry off the roads so I could drive this thing for the first time!

[johnkuhn]

Got it done and works gerat. Thanks for the help! I did the alternator hook up. Now all I need is the snow to give up. We have 6 inches today with 6 more coming yet tonight!