Kill Switch

[Anon]

Hello,
Our team is pretty new and we are looking to take part in FSAE 2015 Italy.
We had a doubt in the wiring of the kill switch of the car. The rule states that both master kill switches should be connected to alternator. But nothing is specified about battery for secondary master kill switch. Does that mean that the secondary kill switch should just shut off the alternator but not the battery? Or should it shut down both?
Also, if anyone could share the circuit diagram of their old FSAE car, it would be very helpful for us since it is the first time we are participating in FSAE.

[Jonny Rochester]

Your kill switches should either open circuit the battery, or at least cut power to the ECU, or cut power to the ignition or all of the above. Additionally it should be wired such that when a switch is hit, it should not be possible for the alternator to continue to power the ECU and ignition and/or fuel pump to allow the engine to still run. The scrutineers most likely will not check your wiring diagram, it is much easier to run the engine and work the switches to prove it cuts the engine.

We have 3 kill switches, (plus a few more of our own to separate fuel pump, ignition and fan).

Our big red key on the outside of the vehicle is connected to heavy battery cables that cuts the battery when operated. Ours was a simple 2 pole switch, and we didn't think we would have alternator issues. However you can buy the big red key switch with contacts for the alternator also, but we didn't feel the need.
http://cdn.nexternal.com/bimmerworl/images/kill_switch.jpg

We also have a big red kill switch on the dash. And we have another switch under the brake pedal. These switches use light gauge wire, and I think they cut power to the ECU and fuel pump. Basically we have 2 or 3 relays. If any of these switches are tripped all the relays turn off. (I don't have the wiring in front of me).

[Rex Chan]

We run a PDM. By AUS rules, we could do everything through PDM. But in 2013, we ran the grounds of the ign module and fuel pump through a relay that was controlled by the dash kill and BOT. This way, the car (ECU, ADL, fans, etc) is still on, but the engine cannot run. And you cannot accidently turn the logic "off", as may happen in the PDM. :(