Building an Autonomous Vehicle: The Batmobile
Nate 
Kill Switch
We documented how to build a wireless kill switch while making margaritas. It was a ton of fun, so we'll skip the bits of the wireless kill switch system here.
In addition to the wireless disconnect, we had a large, red mushroom kill switch that disconnected the battery with a pleasing and authoritative "thunk." Pulling up on the mushroom button reconnects the battery to the system.
As a pleasant bonus feature, the mushroom kill switch got rid of the nasty sparks. When connecting the battery to the motor controller, there was such an inrush of current into the capacitors and electronics that the connector would spark. Once we got the kill switch installed, we could connect/disconnect batteries without these sparks.
The top of the Batmobile was easily removed, but because it had the kill switch installed we needed a way to disconnect it easily from the power bus. We found a great high-power connector in a dead server UPS. These are often called "winch connectors", because they are higher current. With this connector, we are able to quickly disconnect the kill switch and remove the top when we need to get at the inside of the vehicle.