When learning about electric dirt bikes, it is easy to get confused as to what all these specifications mean for the batteries, controllers, and motors. In this post, I will break down what each of them means and how they related to each other.
You will often see batteries measured in Ah which stands for Amp Hour. This is an important measurement because it directly relates to how far you can ride on you electric dirt bike. Ah is essentially how much energy that a battery can store. This stored energy is what is then transferred to your motor to propel your bike. The more energy you have stored, the longer you can ride and the further you can go. Unfortunately, translating Ah into range is not that straight forward. Similar to your car, the heavier the vehicle, the faster you are driving and/or accelerating, tire size, gearing ratios, can all impact the amount of range you get from a battery.
You will also see batteries measured in V or voltage. Voltage related to how fast your battery can discharge the battery. You can think of it as a the pressure of home facet, if you just barely turn on your facet, water would just trickle out which is similar to a lower voltage. But if you were to turn on your facet full blast, water would start to spray out similar to a higher voltage. So the voltage rating of your battery is the max pressure that energy can be drained from that battery.
So it can be helpful to think of voltage like pressure, but what exactly does that mean for your bike? Well, there is a direct relationship between how fast your motor turns and how high your voltage is. So if you had a 30 volt battery, your motor can only turn half the speed of a 60v battery. So you could think of voltage like speed, but as you can imagine, there are caveats. Your speed will change based on the weight/load that the motor is pushing and your gearing ratio and wheel size.
To understand the controller, you need to know that it essentially works like the brain of your electrical system. To operate the electric dirt bike, we have to connect all electrical components like battery, motor and throttle sensor to the controller. With the help of a controller, you can control the power from the motor, speed of the bike, acceleration of the bike, etc.
You will often see controllers for these Kuberg, Sur-Ron, and Talaria bikes measured by Kw (Kilowatt). This is essentially a measure of the maximum power you can transfer from the battery to the motor.
How it all works together
It may be tempting to get a bigger controller so you can have more power when riding your bike. But before you go making these types of upgrades, you have to consider the capabilities of your motor and battery to make sure it can handle the upgrade. When upgrading a controller, you will need to make sure you battery can even supply the amount of power you want and that your motor is rated to accept the amount of power you are giving it. It is common in bikes like the Sur-Ron that to upgrade to a 15kw charge, you also have to upgrade to a 72V battery.