Battery kill switch help

[Jon-S14]

I need to mount a kill switch for the drags. They told me the kill switch needs to kill the battery and the alternator. Does anyone know how to properly do this? I bought a kill switch with 2 terminals and it's for automotive use. I would know how to kill just the battery but how would i kill the alternator and battery on one switch? How do you guys have this hooked up. I have a s14 and the battery is in the trunk.

[Jon-S14]

Nobody knows?

[nissandr1ft]

You could run a breaker w/ your battery/alt cables on one side, and the rest on the other. Heres what Im going to run... http://i22.ebayimg.com/03/i/000/9b/74/e950_1.JPG

[grnappletree14]

You could run a breaker w/ your battery/alt cables on one side, and the rest on the other. Heres what Im going to run... http://i22.ebayimg.com/03/i/000/9b/74/e950_1.JPG

where did u get that breaker and whats is it called

[trsilvias13]

it should be the same for any car. Just look at other forum where drag racing is a more mention topic. You will get a better idea with their help.
The switch needs to be outside the car just incase. My friend does it to their honda that runs 9's. I run 12's all day. I just get a smaller battery instead of changing the battery location.

[brokeAs240sx]

Is your battery relocated to the back/trunk?

You can get one of the kill switches from summit racing / jegs / etc.

Here's a couple diagrams I made a while back when I was setting up the car for road racing.

Most ppl relocate the battery like this:
http://nissaninfiniticlub.net/photopost/data/590/407diagram-01.jpg

The problem with the above setup is that it will kill power from the battery, but the alternator can still provide power to the car...

So the revised way is like this:
http://nissaninfiniticlub.net/photopost/data/590/407diagram-02.jpg

Requires more wiring, but will basically allow one switch to properly kill power to the car (there's instructions included w/ the kill switches, i.e. one terminal goes to alternator, one goes to battery, one goes to the rest of your stuff).

The same idea applies if you have your battery in the front and wanted a kill switch.

Most people I've seen w/ 240's who have kill switches installed several different ways (there are more, but just to give you an idea on how some s13 guys have done it):

Rear mounted battery:
- drill hole into the rear garnish & mount there (where 240SX emblem is)

- have a spare taillight, drill a hole into the taillight & mount the switch there for track days, but take it off and mount it inside of the trunk normal days - so that no one can just disable your car during a normal non-track day. This way is more trouble, but cleaner if you also daily your car.

Front mounted battery:
- thru front grill/opening by turn signals
- through passenger side fender w/ vents or where the sidemarker is
- through hood

I also believe you have to have a specific set of stickers pointing to the battery cut-off (at least for road racing).

Hope that helps. It's pretty straight forward once you have the kill switch & car at least partially wired.

[Jon-S14]

I found a lead that goes from the alternator to the fuse box. It's basically the lead that goes to the 100amp fuse in my box. I turned on the car and disconnected that lead and the whole car dies and all power is gone. Is it ok for me to hook my kill switch up to that lead and mount it to the front bumper area?

[Jon-S14]

ttt.................

[brokeAs240sx]

As long as there is no power to anything in your car (i.e. the battery doesn't power anything).

A simple way to check is disconnect that, and see if you have any interior functionality (lights, radio, etc), can start the car again, etc.

If you can't, then that will work fine.

[bardabe]

I installed my Alternator and Battery to one pole, then the acc and Ignition to the other pole. that way when they kill the battery i don't have to reset my radio stations. or my clock, or relearn the ECU's set up ! =)

[Taiden]

Most ppl relocate the battery like this:
http://nissaninfiniticlub.net/photopost/data/590/407diagram-01.jpg

The problem with the above setup is that it will kill power from the battery, but the alternator can still provide power to the car...

So the revised way is like this:
http://nissaninfiniticlub.net/photopost/data/590/407diagram-02.jpg

Requires more wiring, but will basically allow one switch to properly kill power to the car (there's instructions included w/ the kill switches, i.e. one terminal goes to alternator, one goes to battery, one goes to the rest of your stuff).

Look at your diagram. It's the exact same thing. The only difference is one has a retarded amount of cable, and the other doesn't.

[brokeAs240sx]

Look at your diagram. It's the exact same thing. The only difference is one has a retarded amount of cable, and the other doesn't.

Actually, no.

Example 1:

- Car is on.
- Cut off switch is pulled (disconnects battery from the car)
- Engine is still on. Why? Because Alternator is still connected to the rest of the car.

You can basically disconnect your battery once your car is on, provided your alternator is working correctly.

Example 2:

- Car is on
- Cut off switch is pulled (disconnects battery & alternator from car)

The only retard I see here is someone who doesn't know how kill switches work...

[Project3328]

owned by brokeass

[Taiden]

Actually, no.

Example 1:

- Car is on.
- Cut off switch is pulled (disconnects battery from the car)
- Engine is still on. Why? Because Alternator is still connected to the rest of the car.

You can basically disconnect your battery once your car is on, provided your alternator is working correctly.

Example 2:

- Car is on
- Cut off switch is pulled (disconnects battery & alternator from car)

The only retard I see here is someone who doesn't know how kill switches work...

sigh. in both of your examples both the alternator and the battery are connected to the kill switch. please refer to your diagram one more time.

yes i am aware of how circuitry works. i am in the process of building a megasquirt ECU. You are telling me something that is clearly not congruent with your diagrams. if you would like me to show you a diagram of a kill switch hooked up with the alternator still live, i would love to.

[bigOdom1]

ok everyone stand shoulder to shoulder we are gonna have a pissing match

[brokeAs240sx]

sigh. in both of your examples both the alternator and the battery are connected to the kill switch. please refer to your diagram one more time.

yes i am aware of how circuitry works. i am in the process of building a megasquirt ECU. You are telling me something that is clearly not congruent with your diagrams. if you would like me to show you a diagram of a kill switch hooked up with the alternator still live, i would love to.

Have you ever seen what a real kill switch looks like? Have you seen how kill switches are hooked up to actual cars?

There's many ways to do this... Let's try one more time since I guess I have to be VERY clear.

For Diagram 2:
Example 1 (most common):
- Kill Switch is 3 terminals (1 to battery, 1 to alternator, 1 to everything else)

Example 2 (cheaper way of doing things, but still works):
- Kill Switch is standard 2 terminals (battery & alternator go on one side, everything else goes on other side)

There's more examples/techniques you can do to lessen the wiring, but that should at least give you a general idea.

The problem w/ diagram 1 is that the alternator cannot be disconnected from the rest of the electronics via the kill switch (well, there is a way, which requires more advanced wiring, some resistors/etc - some spec miata guys do it this way, I can provide several write ups if necessary or you can search).

If you still don't believe me that the 2 diagrams are different, well... i'm sorry, i can't be much clearer than that.


*ADDITIONAL NOTE: Yes, there are ways to keep the main gauge wire going to the trunk a single one & have alternator connected to the ACC/Engine Control/etc, BUT that still requires additional wiring - makes it a bit more complicated & most likely more complicated than what the OP wants to do.

[Taiden]

You are right. Most battery cut off switches that I have dealt with are 2 post. Sorry for the pissing. We can therefor both agree, that if both switches in your diagrams were 2 post, that it would indeed be effectively the same wiring scheme.

Apologies.

[brokeAs240sx]

I'm not trying to be an ass (that much), just trying to clear this up for other ppl.

If both diagrams are 2 post, the diagrams are still different IF you are not doing any additional wiring (i.e. to get it to work w/ the alternator still connected to the rest of the electronics).

In diagram one, w/o any additional wiring, the alternator will keep the car running when the battery is disconnected.

In diagram two, the same will happen IF the alternator is put on the terminal connected to the electronics/controls/etc, since it will essentially be the same as diagram one.

However, if you connect the alternator wire to the battery side of a 2 post terminal, things will be different. When the kill switch is pulled, the alternator & battery will be on one side, effectively cutting off all power to the electronics/controls.

If you know/have the diagram for hooking up the additional wiring for a 2 post kill switch where the alternator is connected to the electronics side, please post it up & explain it. I've read through that kind of setup a few times & still not 100% clear on how to best set it up & exactly how it works.