VESC on/off with voltage key throttle

I’m building an escooter (current progress)

and I’m using a VESC 100/250 with a 72v battery. So far everything is great, but I’d like to have a key switch. These seem to be relatively popular, and the voltage display is a nice perk:

However, the wiring guide seems to be more along the lines of "connect the yellow to battery positive, and the blue to the controller “switch” (negative).

I guess the idea is that it can use the positive to give you the volts and then connect it to the ground when the switch it turned, completing the circuit to let the controller turn on.

That, I don’t think though, is how the on/off on the VESC works – seems more like just an interrupted wire you’ve got to close.

Now, I can just connect the vesc’s on/off to the yellow and blue side as it does seem to act as an open/close circuit with the key, but I’m worried the voltmeter in that same pathway may be problematic. And, even should that work, I wouldn’t get voltage on the display.

Looking for advice or where I’m mistaken. Thanks!

Not sure about that vesc, but I know the spintend ubox v2 has key start support. You may have luck looking at how they do it. Spintend.com

I also just measured voltage by tapping into the on/off mini-jst jumper with a pos multimeter and the negative and get ~36v, but the battery is at 76v right now. It’s not quite half voltage and that’s…really weird, even it was a half voltage thing.

Looks like they have an entire extra interface for doing that which, while three pin, I have no idea if it’s the same or not. The schematic in the manual for the vesc 100/250 is…not very informative about this particular plug.

for the key start to work you either have to wire the cables to an antispark switch or to the switch pin on the vesc. Should work just fine. I did it the same way on an old ebike I have.

Was an answer to using keys ever found?