This is the story of how I was able to take an old broken Gotrax GXL V2 electric scooter and bring it back from the dead. Below are all the steps I went through to get this thing working again. It was fun and rewarding – and in the end it gave me a reliable ride to get around town.
A Broken Throttle
The main issue with this Gotrax GXL V2 was a broken throttle. Apparently, this is a fairly common issue on these scooters. The previous owner had taken apart the entire console of the scooter in an attempt to repair the throttle. This led to me having to epoxy the console back together (the original owner had lost the fasteners necessary). After getting everything back together, I began messing with the throttle cable, which led to my next discovery …..
Fancy Potentiometers
I learned that the throttle and, to some extent the brake, on the GXL V2 are simply very fancy potentiometers. A potentiometer is basically a variable resistor. However, these potentiometers acted as voltage dividers for the ADC on-board the scooter console. This could tell the scooter how much you were pushing on either the brake or the throttle, and send power to the motor respectively.
The Solution
At first, I epoxied an old breadboard onto the console and ran jumper wires to a simple breadboard potentiometer. This proved my theory of the throttle and brake being fancy potentiometers, but it was honestly incredibly difficult to control and wouldn’t lead to anything good if used on public roads.
The Backwards Idea
I realized something – it’s more important to be able to control your acceleration than your braking force. As long as your brake is strong enough, you don’t need to be able to control how slow you brake. Following this idea, I connected the throttle to the brake.
That’s right, because the brake was still functioning and the throttle wasn’t, I simply connected the throttle to the brake. You may be asking – How would I brake?
In order to brake with this setup, I simply used a push button and made a “pretend” voltage divider, so when the button was pressed the console would think to brake as hard as possible. This made for a fairly abrupt stop, but a safe stop nonetheless.
The Aftermath
This design lasted me about six months, until I bought a moped. Overall, it was very reliable for the band-aid job it was, and I had a ton of fun building it. I highly recommend trying it if you ever get your hands on a broken e-scooter.
