Wiring a NHRA Kill Switch
Thread Starter
Staging Lane
Joined: Nov 2010
Posts: 50
Likes: 0
From: Florence, Alabama
Wiring a NHRA Kill Switch Planning out the kill switch for my trunk mounted battery. Engine is an LS2 in a 240z. This is an 11.0 car that I intend to spray in the near future. Alternator is from an F-body LS1. I already have 0 gauge + and - cables run from the battery to bulkhead connectors on my firewall, and I have branched all the constant hot circuits from that bulkhead. I understand that I have to kill not only the + voltage from the battery, but all so the + voltage from the alternator that charges the battery. Is there a way to kill the power from the alternator without running another another (or another pair) of heavy gauge cables from the alternator (in the engine compartment) all the way back to the kill switch (which is in the back of the car by the license plate)? I just don't want to add the weight of another set of heavy 15' long cables if there is another, more weight and work conscious way. With all due respect, please respond only if you have done this modification to your car, so I don't get too many speculators-I really want to know what WILL work rather than what might work. Please tell me what switch you've used. Thanks.
I purchased my battery relocation kit from Burkhart which came with the switch, so I don't know what specific brand it is. You do not need to run two new cable for the alternator because it grounds to the engine block. You only need to run one 6 gauge wire from the alternator to the positive side of the battery or to the same side of the switch as the battery lead.
Yeah like said, the alternator can go to the battery directly or the battery post on the switch. The other side will run up to your starter and you can use that post to run another lead to your fuse box lead etc. Its pretty simple and without seeing your actual setup I can't give you more direction.
Thread Starter
Staging Lane
Joined: Nov 2010
Posts: 50
Likes: 0
From: Florence, Alabama
Thanks, fellas. 6 gauge is heavy enough for the distance from the alternator to the battery in the trunk? I'm not good with electrical concepts: why do I need a 1 or 2 gauge from the battery, but only a 6 from the alternator? Perhaps because you crank from the battery? I'm really exicited that I only need one wire and not two. Just a bit more coaching please.
Because the wire from the battery to.the starter needs to carry the full 600-700 amp cranking capacity of the battery. The alternator only puts out 100-120 amps. The wire is sized according to amp capacity for the circuit it is completing.
Also I saw your other thread and you don't need that fancy switch.
Also I saw your other thread and you don't need that fancy switch.
I personally like to run the largest wire I can. I run my alternator wire all the way to the battery in the trunk in an fbody so its probably close to 20 feet of wire. I use 1/0 and at minimum would use 4 gauge. The greater the distance, the more resistance.
