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How Does the E90 Know It's Going 3mph? Encoder?

I'm trying to modify an E90 and would love to be able to play with the safety feature that it only activates the throttle once it's going 3MPH.

I looked on the rear wheel, and couldn't find an encoder. Is the controller reading in current from the motor spinning? If so, how does it do that?

Thanks for any help! You guys are great!


The Razor E90 electric scooter's controller reads the Voltage that the motor generates when the scooter is in motion before it will send power to the motor. I do not know how the controller reads the Voltage that the motor produces but I assume it would be through a Voltage comparator circuit.

I do not know how to modify the controller to disable the push to start feature. The only thing I could recommend would be to install a different speed controller and throttle that is variable speed and does not have a push to start feature.

That makes sense, thanks for your help!

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