Devoid of friction braking that is typical of moving vehicles such as cars, motorbikes, and even bicycles, electric skateboards have to rely on regenerative braking and dynamic braking. While friction braking is very effective at stopping a moving vehicle, it requires bulky and often time heavy mechanical parts. This is not feasible in a compact last-mile tool like the electric skateboard. This is where VESC regenerative braking comes in.
One of the biggest draws to electric skateboards is its ability to brake. You might love to push your board without electric assistance. You might love the lightweight nature of traditional electric skateboards. You might fall in love with the ease of curving with your regular skateboard.
However, you cannot be comfortable with the braking capabilities of a regular skateboard during fast rides, especially when going downhill.
Electric skateboards using VESC regenerative braking will help you take on the steepest hills, knowing you can comfortably and safely brake whilst going downhill. Having been using electric skateboards for a while now, I have come to appreciate the importance of braking performance.
As such, I have scoured the internet to understand braking in electric skateboards. In this read, I will share with you everything you should know about e-skateboard braking, especially the most common type of braking – VESC regenerative braking.
Electric Skateboard Motor Design
To understand the braking mechanisms of electric skateboards, you need to first understand how the electric skateboard motor functions. The vast majority of e-skateboards use outrunner motors. These are brushless DC motors whereby the outer shell spins around the core winding. When an electric current is supplied to the core winding, an electric field is created, causing the ring of magnets to spin.
This spin/rotational force is transferred to the wheels via a pulley system in the case of belt driven electric skateboards. In the case of direct drive electric skateboards, the wheels are attached to the outer spinning ring. As as the spin ring of magnets spin, so do the wheels.
The outrunner motors tend to have a higher number of poles as compared to inrunner motors. As such, they tend to be much slower than inrunner motors. However, they also have their own advantages. For instance, the outrunner motor is capable of producing far higher torque than the inrunner. Given that the motors have to power the e-skateboard over hills, more torque is welcomed.
Another beneficial characteristic of the outrunner design is its behavior when you rotate the magnets around the copper winding. This action induces an electric current into the copper wire.
The Outrunner Motors Design And VESC Regenerative Braking
VESC regenerative braking takes advantage of the fact that you can turn the motor into a generator of some sort. Given that the process that induces an electric current into the copper wire also induces resistance into the system, it is perfect for braking. The resistance slows down the wheels, thereby providing effective braking.
On the other hand, the electric current produced during the process is fed into the battery cells, thereby recharging the batteries. That said, you should note that the effectiveness of the recharge is influenced by the battery management system used in your electric skateboard. Some battery management systems and settings are not optimized for regen charging. As such, the effective battery charge will be small to negligible.
Moreover, your riding style and the environment you are riding on will also influence the regen effectiveness. You can read more about regen charge here.
It is also influenced by battery capacity. If your battery is already full or nearly full, you cannot use regen braking for a long time as the batteries cannot take up the additional charge that is being fed back into the battery system. Otherwise, if the current is fed back into the motors, the additional charge will negatively impact the longevity of the battery system.
It is for this reason that electric skateboard users are advised not to skate down a long steep hill on a full charge. Some e-skateboards such as Boosted Board and Koowheel Boards will notify you when the regen brakes are about to fail.
VSEC Dynamic Braking
Aside from VESC regenerative braking, there is another type of braking in use in some of the electric skateboards – the dynamic braking. Unlike the case with regenerative braking whereby the electric generated is diverted back to the battery cells, dynamic braking uses a different setup where the current is fed to a resistor. As such, this setup includes additional components, chief among them a resistor.
When the VESC is instructed to brake, the kinetic energy in the wheels is spin the magnetics around the copper wire. This induces a current and some resistance, very much as is the case with regen braking. However, the electric current is diverted to a resistor where it converted to heat, thereby converting the kinetic energy to heat that is lost to the environment.
The good thing about the dynamic system of braking is that you can use the brakes even your battery is fully charges. As such, if you live atop a hill, and the first time you hit the road with your e-skateboard is going downhill, you can use dynamic braking without destroying your battery. Additionally, dynamic braking adds a layer of redundancy to your braking capabilities, which improves the overall safety of the skateboard.
One of the electric skateboard available with kind of braking is the Mellow Drive. Check out these Mellow Drive videos below that explain this system.
Safe Electric Skateboard Braking
Effective braking is one of the most important safety considerations when choosing your electric skateboards. However, you can rely solely on regen braking and dynamic braking (when implemented in your e-board). You need to have the option of slowing down your board in the absence of regen braking.