Topic: Kill switch installation
Can the kill switch operate like the stock ignition and cut power via relays, or does it need to be wired directly into the battery and alternator cables?
The 24 Hours of Lemons Forums → Lemons Tech → Kill switch installation
Can the kill switch operate like the stock ignition and cut power via relays, or does it need to be wired directly into the battery and alternator cables?
It should be a double throw switch that disconnects both the ignition and the battery.
http://www.pegasusautoracing.com/produc … RecID=1464
Can the kill switch operate like the stock ignition and cut power via relays, or does it need to be wired directly into the battery and alternator cables?
Can a relay fail and the engine still run with the kill switch in the "OFF" position?
It should be a double throw switch that disconnects both the ignition and the battery.
I understand that, and the stock ignition switch (on the steering column, where the key goes) does both of those things via relays. If I install a kill switch that activates in the same fashion, is that acceptable? Or do I need to have a kill switch that cuts the ignition and battery/alternator by interrupting the large-gauge battery & alternator cables directly?
I added a link to my post:
http://www.pegasusautoracing.com/produc … RecID=1464
You want a kill switch that disconnects all power from the battery, you don't want a battery short in a crash. A proper disconnect will have a large high current connection for your battery and low current for your ignition or alternator.
dinomite wrote:Can the kill switch operate like the stock ignition and cut power via relays, or does it need to be wired directly into the battery and alternator cables?
Can a relay fail and the engine still run with the kill switch in the "OFF" position?
I don't believe so.
Another way to ask my question, is how (not where, which is thoroughly covered http://forums.24hoursoflemons.com/viewt … p?id=2162) does everyone else install their kill switches?
In both of our Lemons we have the battery mounted to the passenger floor with a master kill switch within close reach of the driver. We have a second kill switch on the outside of the car on the right side for a corner worker to hit in an accident and the driver cannot. Either switch will completely kill the car as they are wired in series.
RobL wrote:dinomite wrote:Can the kill switch operate like the stock ignition and cut power via relays, or does it need to be wired directly into the battery and alternator cables?
Can a relay fail and the engine still run with the kill switch in the "OFF" position?
I don't believe so.
Rhetorical question. Yes, a relay can fail and stay in the engaged position and leave the car running even if you throw the kill switch.
dinomite wrote:RobL wrote:Can a relay fail and the engine still run with the kill switch in the "OFF" position?
I don't believe so.
Rhetorical question. Yes, a relay can fail and stay in the engaged position and leave the car running even if you throw the kill switch.
Heh, OK. That clears up my question, then. I guess I need to get some good lengths of large gauge cable.
You might be able to go to a local car audio shop and get some "scrap" battery cable that's just sitting around. They charged me $1/ft for a 10ft length they had in back, which beats the ~$2.50/ft it's running right now.
Your local autoparts store will make any length you want and even crimp on the connectors for you.
Jumper cables.
Just don't use your only set, you may need them at the track
Go to your favorite Junk Yard, find an older BMW 5 series 4 door and you will find a nice 12' long 00. gauge battery cable sitting underneath the back seat. Older BMW's had their batteries in the trunk and they ran all the way to the front engine compartment on the passenger side. Ours cost $6.00 bucks at pick and pull cause they can only charge what they post on their price list.
Go to your favorite Junk Yard, find an older BMW 5 series 4 door and you will find a nice 12' long 00. gauge battery cable sitting underneath the back seat. Older BMW's had their batteries in the trunk and they ran all the way to the front engine compartment on the passenger side. Ours cost $6.00 bucks at pick and pull cause they can only charge what they post on their price list.
If dinomite is who I think it is, there are at least 2 x 5 series at the Baseline Rd U-Pull-It...
If dinomite is who I think it is, there are at least 2 x 5 series at the Baseline Rd U-Pull-It...
If I'm right that the Baseline Road joint is in Little Rock, then I don't believe I'm the person you're looking for. Thanks for the tip, though!
-Drew
Go to your favorite Junk Yard, find an older BMW 5 series 4 door and you will find a nice 12' long 00. gauge battery cable sitting underneath the back seat. Older BMW's had their batteries in the trunk and they ran all the way to the front engine compartment on the passenger side. Ours cost $6.00 bucks at pick and pull cause they can only charge what they post on their price list.
1990-1993 3 series Beemers also have this cable.....Snagged two last week!
1990-1993 3 series Beemers also have this cable.....Snagged two last week!
The entire e30 line of BMW's has the long length of cable to the trunk. Look for the 4-door e30 models especially, their cables are a little bit longer. Solid copper cable. It's really amazing stuff. It's so thick and masterfully wound that I think maybe it has negative resistance. Might even be superconducting at room temperatures...
Relays and contactors:
Relay contacts can weld closed, under high fault current. They can also weld with heat from being corroded.
Our e36 has the same cable. Splicing into it and finding connectors was a real blast.
The 24 Hours of Lemons Forums → Lemons Tech → Kill switch installation