Slamland 2

Part 2 (methods)

There are basically only two forms of vehicle available today; Electric Vehicles (EV) and Fueled Vehicles (FV). Hybrids are a special case of Fueled Vehicle¹ . There is some very cool stuff on electric transportation at Jay Leno’s Garage.

EVs

What makes an Electric Vehicle (EV) unique is that it only uses energy. It does not generate any energy. It gets all of its energy from external sources and stores it on board in a battery. It then converts that energy into motive power as needed. When the battery is depleted, it needs to be recharged from an external energy source. This is where the zero-pollution and zero-emissions hyperbole stems from.

I had a link to the video of Jay Leno’s 1909 Baker Electric but it won’t load properly. Therefor, I only present you this link to the original article.

Note that I am making a careful distinction between energy and power. Energy is measured in Watt-Hours (Wh) and power is measured in Watts (W) . This is not just a semantic difference. It isn’t energy that moves you down the road, it’s power and that’s measured in Kilowatts. The power of automobile engines are often rated in horsepower (HP) rather than kilowatt (kW)² . The word "horsepower" may give you an intuitive idea that power defines how much "muscle" a generator or motor is capable of, whereas energy tells you how much "work" a generator or motor performs during a certain period of time³ .

Batteries are rated in Kilowatts-hours (kWh)⁴ as they are actually energy stores. Batteries are Direct Current (DC) storage devices but power can be much more efficiently manipulated in Alternating Current (AC) form⁵ . Therefore, there is a converter between the battery and the rest of the system ⁶ .

This becomes very useful later when I convert the fuel stored in an FV into kWh in terms of comparison. This very important in terms of avoiding comparisons of apples and oranges or cumquats and bananas. I will not be comparing the Tesla Roadster versus the Honda Civic. Performance-wise, it is much more fair to compare the Tesla Roadster Sport against a Shelby Mustang GT, given their relative performance specifications. Likewise, the Aptera⁷ is better compared to a Smart Car although a better comparison is Smart’s own EV⁸ .

Power (W)=Current(A) * Voltage (V) ;Where current is measured in Amperes (A) and Voltage is measured in Volts (V).

Energy(Wh)= Ampere-Hours (Ah) * Voltage

History

EVs have been on the scene for over 100 years⁹ . The oldest one that I know about is the 1909 Baker Electric.

Although a crude electric carriage was originally created in Scotland in the late 1830s, the first functional electric car in the United States was produced in 1891. For the next decade, the clean, quiet electric car was the king of the road. In 1899, an electric car broke the vehicular land speed record, and by 1900, there were more electric cars than any other kind in the U.S., accounting for 38% of the nation’s car market. – Jay Leno

In contrast, the first gasoline powered FV didn’t appear until 1898.

1. Interestingly, steam powered cars are also a Fueled Vehicle but that’s out of scope for this series. [↩]
2. 1 kW = 1.359 HP. In Europe, engines are actually rated in terms of kW, rather than horsepower (HP), by regulation. I may sometimes give both but, I will be using kW in the actual calculations.  [↩]
3. Windpower.Org actually has a very good description of this. This will actually be very important later when we discuss energy density issues under the energy sources portions of this series. [↩]
4. 1 kWh= 1 thousand Watt-hours [↩]
5. This is why you have AC power on the electricity grid. [↩]
6. A DC-AC power inverter going out and a rectifier, going in. As a trained Electrical Engineer, I would be sorely remiss in not pointing out that AC and DC power calculations are very different. However, at these scales, they do not result in significant variations to prevent using DC calculations as a First Order Approximation, which is all we need here. Were we designing an actual EV, we would be requiring the  actual AC formulae. Were we designing at the scale of a power grid (Megawatts, mW, 1mW=1 million Watts ) then I would perhaps be using the AC calculus as well. [↩]
7. The Aptera appears to be on the road to extinction due to the massive stupidity of the current CEO. [↩]
8. If I can obtain the data. ATM, this is doubtful. [↩]
9. a crude electric carriage was originally created in Scotland in the late 1830s. The first functional electric car in the United States was produced in 1891 [↩]

Mirrored from The Slamlander.