E-Skateboard project needs general tips

Hi Everyone,

Haven't posted here in so long, and am trying to get back into Arduino. (so, I'm basically a noob)

I want to make an electric long board, and need to ask some questions about motors:

would a NEMA 17 stepper work? I've seen a lot of e-boards using brushless, but none use steppers. Is there a reason for this? (planning on hooking up 2 nema 17 Holding torque: 5.5 Kg-cm on rear wheels)

Steppers have very low efficiency and are not suitable for this application. Also they do not normally have enough power.
Think of it like this, a electric bicycle has normally a motor of 250W which is sufficient. But a bicycle has a much lower rolling resistance than a skatebord. Taking into account that the speed of a skateboard also is lower the power needs can be considered equal.
5,5 kgf.cm equals 0,54Nm. If you tighten a screw with a screwdriver you get about 2 Nm so you will have 1/4 of that, it is questionable id that torque even can move the skateboard at all with some load on it.
Next, even if they would it is difficult to get higher revs from a stepper. Lets say you gett 300rpm, that will get you going in 2,8 km/h or 1,75 mph. In order to get that speed you will have to carry a battery of at least 30V.
The curretn drawn at that torque will be about 1,5A. That means electrical input power is 45W. mechanical output power will be 0,54*300/9,55 = 17W that means an efficiency of 37%, way too low

Thanks Nilton, I think I'm going with BLDC motors for RC trucks. :slight_smile:

A big problem with stepper motors is that you are always driving them at maximum current, regardless of the load.

Here's an 150A ESC