What Are Electric Vehicles All About?
Written By: Jason Shilee Ma
Since the first motorcycle was invented in 1885, the industry itself has become familiarized with abbreviations and technical automotive terminology that we don’t even think twice when using anymore. But with the introduction of electric vehicles, it has brought along with it a new lingo that changing the game.
Even if some of us don’t really understand the true engineering behind a motorcycle, we’re still familiar with basic terms such as power and torque — whether it’s measured in imperial units or along the metric system. Going even deeper, anyone who owns a motor-vehicle at least understands the basics of fuel economy and the exchange between gasoline and distance. Now what about electric motorcycles?
When it comes electric motorcycles, the language completely changes. All of a sudden, complex words such as volts, watts, amps, and ohms are dropped on us, and most of us haven’t got a clue. If we’re being told that a motorcycle has a 600cc four-cylinder engine, most of us would at least have a rough idea on the size of the bike, its weight, and to what extent it will be able to perform. Tell us it has a radial flux, permanent magnet, brush-less DC motor and 13kWh Li-Ion battery and we’ve no idea whether it’s something you could hold in one hand or if it will fill a warehouse.
Hopefully this article will help you clarify some of the confusion you may already have, and educate you on what to look for when you decide to purchase your new electric motorcycle.
The first reaction that most people immediately have about motorcycles is of the traditional internal combustion engine and the thick smell of gasoline in the air.
Combustion engines are actually heat engines, they take thermal energy from burning fuel and convert it into mechanical energy which then propels the bike forward from start to end-destination. Gasoline is merely a chemical tool in this entire process and once mixed with oxygen from the airs, a reaction takes place which creates heat to run the engine.
Electricity acts quite differently in its own nature, flowing like a current through wires from the battery to the electric motor. Currents are weightless, can’t be seen, nor can they be smelled. It’s quite a phenomenon in and of itself.
One vocabulary word some of us are familiar with is volts (V). Whether you’re talking about the 12V battery that start your bike, the 230V sockets in your house or the 1.5V AAA batteries that sit inside your TV’s remote control, it’s one electrical term that we use quite regularly, even without knowing exactly what it means.
Voltage refers to the electrical potential difference between two points. That might be 1.5V between the positive and negative terminals of an AAA battery or 400,000V (sometimes more) between cables on overhead pylons and the ground.
Electricity is perhaps best understood using an analogy comparing it to water flowing through a pipe. In this analogy, the voltage could be compared to the pressure of the water in that pipe.
When we speak of Amperes (Amps), we are actually talking about the current of an electrical system. If we can equate volts into water pressure in our pipeline analogy beforehand, then amperes (A) would be the volume of water coming through that pipe over a certain amount of time, representing the rate of flow of the electric charge.
You can have high voltages with low amperage — think of a small hose running at a high pressure — or high amperage and low voltages, like a big pipeline with only a trickle of water running through it.
Because of the connection between volts and amps, you can trade off one in return for the other. For example, it is simple to purchase an inverter that has the ability to plug into a car’s 12V DC output and make it into a 240V AC output. That’s 20 times as many volts, but there will also be 20 fewer amps in return. So, while you should easily be able to power a 240V AC device, you won’t be able to run any high-powered appliances from the outlet with power. Serious power comes from combining high amperage and high-volts together, which brings us to our next topic the watt.
In the electrical motorcycle world, kilowatts (kW) are used to express the power among bikes, 1kW is equivalent to 100 watts (W). When we talk about watts, it’s usually in regards to how much power or work is done over time. And because you often need so much of it, we tend to use it as a unit of kW to prevent the numbers from getting to confused or all over the place.
Watts are equivalent to amps multiplied by volts in an electrical system. On a typical ICE bike’s battery, for instance, you might read specs like 12V, 150A CCA. In this regard, it pretty much means that it can put out 12V at 150A (cold cranking amps) for short-term periods of time. Since watts are current multiplied by voltage, our calculation in terms of power would be 12 x 150. That’s 1800W, or 1.8kW. So from this understanding we can say that for a battery to provide enough energy to run the whole bike, it would need to be a whole lot bigger.
One of the most important components in respect to performance and range of an electric motorcycle is the battery component. And from the battery, the kWh figure, which stands for kilowatt-hours, is a representation of its total capacity.
It’s not too complicated of a concept if you stop to think about it — a kWh represents how many kilowatts (kW) of power a battery can produce for an hour. If you look at it from a different perspective, how many hours the battery will be able to continuously produce for 1kW of power.
Confusingly, a lot of batteries (like the ones in our ICE-powered bikes) will tell us their amp-hour (Ah) capacity rather than give a Wh or kWh figure. However, we’ve already seen that watts are amps multiplied by volts, so we can work it out.
A typical lead-acid, 12V bike starter battery might have a 20Ah capacity. That’s 20 x 12, so 240Wh, or 0.24kWh. A car battery, while still 12V, might have 100Ah capacity, giving it 1200Wh or 1.2kWh.
Given that even the smallest, 50cc scooters make around 2.5kW of power, and a super-bike might make 150kW, you can see that to get any meaningful range from a battery-powered bike you’ll need rather more capacity than that.