DIY Throttle Limiter
Permanently capping an electric scooters speed can be most easily achieved by limiting it's throttle output. This is important in countries where a device speed limit is regulated by law (eg. 25km/h in Singapore). Many scooters available for sale in the various markets exceed these limits.
Adding a variable resistor to the throttle output is the cheapest and easiest DIY solution. The resistor costs just a few cents and requires only basic electrical knowledge to install. This works for any electrical scooter or e-bike.
Once installed you will need to tune the resistor until 'full throttling' gets you to the top speed you desire.
NOTE: common throttle wire coloring is Red(+5V), White or Green(Signal), Black(0V)
A 10K Ohm resistor or trimpot works well.