Wiring in the alternator to a battery cutoff switch
Jun 5, 2012, 07:18 PM
#1
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Wiring in the alternator to a battery cutoff switch
Hi all,
I'm looking to install a cutoff switch for my truck mounted battery so that it will pass track inspection. I know how to hook it up to the battery but I have heard that unless you hook the alternator up also it is pointless because the alternator will still run even if the switch is turned off during an emergency. Has anyone here ever done this and how did you wire it to where the alternator turns off? I've also heard of people wiring in the fuel pump instead of the alternator. I've searched and all I can come up with is how to wire it to the battery.
Also, I've thought about setting it up to where I pull my passenger tail light out at the track and hook up the switch through one of the holes, since I also DD the car. Has anyone ever done this? I don't really see any issues.
Thanks in advance
I'm looking to install a cutoff switch for my truck mounted battery so that it will pass track inspection. I know how to hook it up to the battery but I have heard that unless you hook the alternator up also it is pointless because the alternator will still run even if the switch is turned off during an emergency. Has anyone here ever done this and how did you wire it to where the alternator turns off? I've also heard of people wiring in the fuel pump instead of the alternator. I've searched and all I can come up with is how to wire it to the battery.
Also, I've thought about setting it up to where I pull my passenger tail light out at the track and hook up the switch through one of the holes, since I also DD the car. Has anyone ever done this? I don't really see any issues.
Thanks in advance
Jun 6, 2012, 10:20 PM
#3
I just did this. I've taken a bunch of pictures and can give you a how to.
I recommend running the T1 Race Development Battery Kill switch. It runs a solid state kill switch with a remote simple switch. Here it is below.
Mount the solid state (black thing with heat sink and 4 terminals) in the engine bay. Battery and alternator go to one side...and the rest of the things that are powered by the battery go on the other side. Pretty easy to use all the OEM connectors and fuse assemblies with this too!
the 12v red wire goes to the battery so it is always powered... ( I connected mine to the terminal that was connected to the battery) and the ground wire (black wire) goes to the Switch with the arming cover that is mounted at the rear of the car. I mounted mine on my rear bumper. The arming switch has the other pole grounded to the chassis.
Link to part I purchased.
http://www.t1racedevelopment.com/ind...hk=1&Itemid=72
I'll have a full write up on it here shortly. I would highly recommend getting this kit from Tony. Super simple and works really well on an Evo.
I recommend running the T1 Race Development Battery Kill switch. It runs a solid state kill switch with a remote simple switch. Here it is below.
Mount the solid state (black thing with heat sink and 4 terminals) in the engine bay. Battery and alternator go to one side...and the rest of the things that are powered by the battery go on the other side. Pretty easy to use all the OEM connectors and fuse assemblies with this too!
the 12v red wire goes to the battery so it is always powered... ( I connected mine to the terminal that was connected to the battery) and the ground wire (black wire) goes to the Switch with the arming cover that is mounted at the rear of the car. I mounted mine on my rear bumper. The arming switch has the other pole grounded to the chassis.
Link to part I purchased.
http://www.t1racedevelopment.com/ind...hk=1&Itemid=72
I'll have a full write up on it here shortly. I would highly recommend getting this kit from Tony. Super simple and works really well on an Evo.
Jun 8, 2012, 03:41 PM
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Thanks, this looks like a nice product! I guess my question is now, what do I rewire on the alternator and where does the other end of that wire go currently so I can figure out what to do with it
. I was interested in this too and I hate trying to figure out wiring (gives me a headache).
Jun 12, 2012, 07:46 PM
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Wouldn't this be different for a trunk mounted battery, since I have 1 wire running through the car to the fuseable link that's for the entire car? How would killing power to the fuseable link that is for EVERYTHING not shut the car off?
If I have to have a wire to the alternator, I'm just confused as to which wire I need to cut on the alternator and run to the kill switch, and back to the alternator. Do I HAVE to splice at the alternator, or can I go farther up the line? Can I just hook the switch into the ignition wiring under the dash? (I think it's the black/ white striped wire)
I'm sure I'm over thinking this way too much
If I have to have a wire to the alternator, I'm just confused as to which wire I need to cut on the alternator and run to the kill switch, and back to the alternator. Do I HAVE to splice at the alternator, or can I go farther up the line? Can I just hook the switch into the ignition wiring under the dash? (I think it's the black/ white striped wire)
I'm sure I'm over thinking this way too much
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Jun 12, 2012, 08:37 PM
#8
You need to interrupt the battery. Problem with that on the Evo (and many other cars) is that we have an alternator. The alternator which is spinning because the engine is running is producing electricity! Since it is connected to the positive battery terminal and therefore to the wires powering the ignition, ecu, injectors etc... the electricity has a direct path to flow from the alternator to the car. Which means you still have power.
For it to kill the car, you have to interrupt the field wire controlling the alternator... or interrupt the power wire from the alternator.
Easy for us... the alternator power wire is already wired to the battery. Which means that you install the power cable and the alternator wire to ONE side of the t1 kill switch. And all the electrical outputs to the otherside of the switch.
Then you mount the kill switch on the rear of the car.
For it to kill the car, you have to interrupt the field wire controlling the alternator... or interrupt the power wire from the alternator.
Easy for us... the alternator power wire is already wired to the battery. Which means that you install the power cable and the alternator wire to ONE side of the t1 kill switch. And all the electrical outputs to the otherside of the switch.
Then you mount the kill switch on the rear of the car.
Jun 13, 2012, 05:04 AM
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Makes sense to me now. Last question, which wire do I need to interrupt on the alternator. What color is it and is it it attached to the fuseable link thats usually on the positive battery post? Thanks for all the help R/T, electricity isnt my strong suit!
Jun 13, 2012, 08:18 AM
#10
It's black and it is attached to the positive terminal. It is not directly fused ( may have a fusable link). It's about 2/4awg and the wire come from the back of the engine bay. Because the t1 unit has posts it's easy to enlarge the hole on the terminal and put it on the post. I've taken a bunch of pictures and I hope to have them posted here soon
Jun 13, 2012, 07:40 PM
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Wow, it just clicked for me lol. All I have to do is take the black (blue stripe?) off the terminal block, hook it and the battery cable to the "IN", hook the terminal block to the "OUT", then take the small red 12v, wire that to the "IN", then run the "GRD" to the trunk switch. I was definitely WAYYYY overthinking this. Thanks!!!
Jun 13, 2012, 09:50 PM
#12
Wow, it just clicked for me lol. All I have to do is take the black (blue stripe?) off the terminal block, hook it and the battery cable to the "IN", hook the terminal block to the "OUT", then take the small red 12v, wire that to the "IN", then run the "GRD" to the trunk switch. I was definitely WAYYYY overthinking this. Thanks!!!
Mar 3, 2013, 07:29 AM
#13
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Sorry to bump an old thread but trying to figure out how to get my car NHRA legal but still keep my car safe when being parked. The car has an aftermarket alarm on it, so it'd be nice to have a kill switch installed but make it to where someone can't just walk up, flip the switch, then break the window lol.
So would I need to install a second switch inside the trunk rendering the bumper switch useless until I go to the track?
This would be a no brainer if the car was a track only car.
So would I need to install a second switch inside the trunk rendering the bumper switch useless until I go to the track?
This would be a no brainer if the car was a track only car.
Dec 11, 2013, 08:13 AM
#14
It's black and it is attached to the positive terminal. It is not directly fused ( may have a fusable link). It's about 2/4awg and the wire come from the back of the engine bay. Because the t1 unit has posts it's easy to enlarge the hole on the terminal and put it on the post. I've taken a bunch of pictures and I hope to have them posted here soon
Image stolen from this thread: https://www.evolutionm.net/forums/ev...nator-top.html
Aug 30, 2017, 04:56 PM
#15
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Bumping an old thread just in case someone stumbles across this like I did, and is getting incorrect info.
The kit from T1 comes with a switch, but is overpriced. Here is the link to that killswitch they sell from the manufacturer. (if you have your own switch already it's a bargain). Luckily I knew how to search for products on electronics sites where I buy parts for my robots and found it.
Data Panel 200AMP Kill switch
Anywho, the wiring is exactly described as here, BUT, connect the battery dist block and the battery source cable to the IN terminal. The black/blue wire is the alternator charge wire. The red/white is the field wire which needs to be interrupted. This is the wire on the distribution block with the "ALT 100A" fusible link.
Everything else goes to the OUT terminal (alt charge wire, starter wiring, and whatever other things you had running to the positive terminal)
This insures that the car will shut off as desired. Good luck to anyone out there who wants to install.
That said...if you aren't using this type of solid state relay killswitch (which honestly you should, solid state is much better than mechanical stuff), remember which wire it is you need to interrupt. The red/white that was going to the 100A fusibile link is your wire. If you use another type of switch, make sure you use heavy gauge wires and a 100A inline fuse to the switch terminal. The current draw and distance requires it, otherwise you'll start melting stuff when you surge (AC turns on, etc). Don't ask me how I know...haha
The kit from T1 comes with a switch, but is overpriced. Here is the link to that killswitch they sell from the manufacturer. (if you have your own switch already it's a bargain). Luckily I knew how to search for products on electronics sites where I buy parts for my robots and found it.
Data Panel 200AMP Kill switch
Anywho, the wiring is exactly described as here, BUT, connect the battery dist block and the battery source cable to the IN terminal. The black/blue wire is the alternator charge wire. The red/white is the field wire which needs to be interrupted. This is the wire on the distribution block with the "ALT 100A" fusible link.
Everything else goes to the OUT terminal (alt charge wire, starter wiring, and whatever other things you had running to the positive terminal)
This insures that the car will shut off as desired. Good luck to anyone out there who wants to install.
That said...if you aren't using this type of solid state relay killswitch (which honestly you should, solid state is much better than mechanical stuff), remember which wire it is you need to interrupt. The red/white that was going to the 100A fusibile link is your wire. If you use another type of switch, make sure you use heavy gauge wires and a 100A inline fuse to the switch terminal. The current draw and distance requires it, otherwise you'll start melting stuff when you surge (AC turns on, etc). Don't ask me how I know...haha
Last edited by jmrussell89; Aug 30, 2017 at 05:05 PM.
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