The box of solid state electronics that sits between the battery pack and the electric motor is the speed controller, communication with an electronic twist throttle tells the speed controller how much to vary the voltage going to the electric motor and thus controlling the speed of your motorcycle from a crawl, all the way up to full speed.
There are two main types of golf cart motor speed controllers, those for Series Wound motors and those for SepEx motors also known as Shunt Wound, and they are not interchangeable.
Less common in Golf Carts and NEV’s are 3 Phase, or brushless AC motors and they are ideally matched with a motor controller/3 phase inverter.
How many Amps a speed controller is rated for can be deceptive.
You’ll see the peek rated or labeled amps of a controller and depending on the company it might be what it can put out for 10 seconds or others it’s up to 2 minutes, motors tend to have the same types of ratings, a peek and continuous output.
Depending on your use, you’re going to want to look at the one hour rating , that tends to be around 1/3 or less of the peek rating.
For example if you want a motorcycle that can cruse at 55mph and has a 48v battery pack, a 300amp speed controller with a 125amp 1 hour rating will be working at it’s limits most of the time, so on hills or hot days it might start cutting back where you will feel a loss of power.
A non programmable speed controllers that tend to be burned in with a soft start designed for golf carts, while you can build a motorcycle with one of these controllers, it’s initial acceleration will be slow and might feel less safe if you ride in heavy traffic.
Programming doesn’t have to be rocket science, with Alltrax you’ll need a free download and a cord between the controller and your laptop, then it’s as simple as adjusting the volume on your radio.
Some other brands of controllers can be more complicated or require special programing tools, so it’s worth checking before you buy.