Strangely, in spite of all the posts, I never linked this switch, it seems. This is what I use as a “kill switch”, since it’s mounted on the bars and will kill the current to the contactor, thus opening the main coils, killing the current to the controller. There’s more to that story, but here’s the link: Trail Tech (040-HBS-01) Two Position Handlebar Mount Light Switch
Here’s the rest of the story. This is a 12V rated switch, and when you use a contactor that uses the pack voltage, it’s going to see anywhere from 48V to maybe over 90VDC. That could be a serious problem, if the switch can’t handle the arcing that happens when you switch it. Most motorcycle key switches can’t handle that kind of voltage and you’ll get arcing across the poles, and eventually either a fused or melted switch, and a potentially dangerous situation of not being able to kill the contactor connection. This switch should be used with a 12V relay that is rated for the voltage your contactor needs. See my link below for more about how to set that up.
Emphatically, you should NOT be using switches with voltage far above their specific ratings, especially if they’re rated for AC only.
Read more about all that on my post here: Switches Made Simple.