Do you want to build a rocket board? Do want to make e-bikes eat dust? To build a beast, need 3 things: a big battery, a crafted ESC, and a crazy motor. If the battery and ESC are all set up, the motor option defines the final speed. Let's straighten up to the core, how to choose the motor we needed.
THERE ARE 6 FACTORS, EACH WORKS ON A MOTOR
WHICH? I will explain separately
1. Size
There are 4 digits to denote the size of the motor. Usually, you can see some websites name their motor like 6374 motors,6380motors...ETC. It means that the diameter goes 63 mm and XX mm in length. Also, this measurement indicates the size of the can itself, it can be a slight difference in the exact motor size due to the can design.
We may think that a larger can size means a more powerful motor by logic. In fact, there are a variety of factors to decide the strength of the motor. The structure of the internal design, the magnet shape used, the size of the stator, and the air gap between the stator and can.
Common Case
- Big Size-High Watts
- Small Size-Low Watts
2. KV ratings
If we talk about the KV one thing we should mention is the rpm. The KV means that when 1 volt is applied to the motor and the number of revolutions we got per minute without load. So, the higher KV, the fast the wheel spin, which also means a higher KV, a lower torque.
The electric skateboard outrunner motor usually ranges from 140KV to 220 KV for a hub motor. The hub motors haven't pulleys, belt and gear to reduce the final speed and torque. Hence, the KV of the hub motors is usually much lower, around 80KV-100KV.
Common Case
- Lower KV – lower top speed, higher torque.
- Higher KV – higher top speed, lower torque.
3. Watts
The Watts is used to measure the power, and it is calculated by ampere X voltage. That means, if you want to handle a lot of voltage and ampere, you need a high wattage motor. And a high wattage motor equals more torque and faster…
4. Ampere
All the motor has the maximum current limitation, The ESC max output should be higher than the motor's max current draw of 5%-10% if you don't want to melt your board. If the max output of the ESC is too close to the max current draw of the motor, it will hurt the longevity of the ESC.
So if the individual motor is 50A, the dual motors will be 100A.
You definitely need an ESC with 105A+ maximum current.
Question: If the individual motor is 40A, what's the maximum current of ESC should I get?
5. Voltage
All the Esk8 websites have listed the motor's support voltage in the product detail. Generally, The motor offers a width range of voltage between 3S to 12S(4.8V-43.2V) to support your build.
6. Sensored VS Unsensored motor
The difference between sensored motor and unsensored motor is the start-up. You will feel a smooth start-up with a sensored motor because It always detects the position of the motor. With an unsensored motor, you need a kick push to start and feel the jerky in the meantime.
Nowadays, every board you bought comes with sensored motor, there is even hard to find an unsensored one. But you can turn the sensored to unsensored by unplugging the sensor cable.
CONCLUSION
We can choose the motor according to the purpose we use it. For example, if you are living in a hilly city, a motor with a lower KV motor help to handle the incline. If you are living in an urban with a flat road and trying to have some stimulation, a higher KV motor gives you insane acceleration and top speed. The motor with a bigger size came with a higher watt to enhance the speed. One Last thing, you should never forget to read the motor-supported voltage.