Wiring an On/Off Switch

Hello,

Yesterday I saw an all too familiar thing. A buddy of mine, also running an Schulze 18.97 speed control, plugged in and it just took off - full throttle. Then with cut up arms and fingers, he wrestled the deans out to shut it off. When a high voltage brushless runs away it's not fun. (in this case it was on the bench, but when it spins at full thottle it's scarry) Anyway, we don't know why his radio didn't seem to sync up, he was on the right model and everything worked fine when he tried it again but it makes me relize that we need an on/off switch.

How does one wire an on/off switch into the 18.97? My first thought was to put one in line with the BEC, the BEC uses small power wires and they must not carry much current. I'm sure that's a possible place for it but I wonder, if you split it there, does that force the Speedo not to power up? The speedo has a +/- which WILL have voltage, so will it arm even without a radio signal? My next thought was to somehow have a on/off in the power wires but I'd image given the high voltage and high amperage, that this isn't easy to do.

Any help on this would be greatly appreciated. There are 4 of us at our track who use 18.97's and none of us have any on/off.

Thanks,

DM