Tuesday, 9 Jul 2002

CALGARY, Alberta, Canada

I turn the key to the start position on my homemade 1996 Saturn electric car and hold it for about a second. The soft click that follows is the only indication that the car has started. I push the clutch in and shift into reverse. With your foot off of the accelerator pedal there is no need to use the clutch in the conventional way, as an electric motor does not idle like an internal combustion engine. It simply stops turning and waits for the driver’s next input from the “gas” pedal.

As soon as at least 10 amps of power starts to flow through the car’s power grid, the E-Meter on the top of the dash comes to life, reporting the vital signs to the driver. These meters (or their equivalent from another manufacturer) are an important component of any electric vehicle conversion. A small computer inside is wired into the power circuits of the car, and control signals sent to this unit are constantly monitored. I can use a small switch on the face of the instrument to select from the various reporting functions.

The Saturn’s E-Meter.

In car terms, you can think of the E-Meter as a fuel gauge, but it does a lot more than that. When I first built the car and installed the gauge, it had to be calibrated to this particular vehicle and its combination of system voltage, battery chemistry, and capacity. For example, this car uses 18 eight-volt batteries to store its energy for a total system voltage of 144 volts. The E-Meter knows this because I told it so when I first entered the system configuration into the computer. It also knows that these batteries have a storage capacity of 165 ampere-hours per battery. You might think of these as the functional equivalent of “gallons of gasoline.”

A small device known as a shunt is housed in a protective case under the hood. The E-Meter senses the current flow across this unit, and is able to derive your energy usage patterns while you are driving. From that information, it can calculate the approximate state of charge and total power consumed for your current trip. When I changed my battery pack last week, I had to re-program the computer with the new parameters so that it could accurately monitor and report on the state of the union under the hood.

When you begin driving an electric vehicle, and especially when you have the only one on the road in your state or province, you must develop a Zen-like awareness of its systems and their maintenance needs. This is especially true of home-built electric vehicles such as my Saturn. They are typically one-of-a-kind prototypes, and the builders such as myself are often the only person around that knows how they work. You become aware that there are no filling stations along your route that can help you if you need an energy fill up, and so you constantly watch your E-Meter and the units of power that you are consuming.

Given the limited range ( about 50 to 150 miles) of the current crop of electric vehicles, you put a lot of planning into all of your outings. For example, I know that there are two roads I can take up the large hill between my house and the University Research Park. One road is heavily traveled, while the other is not. By taking the less-traveled route, I am able to limit the current flowing to the motor by simply slowing down the car. Less current used translates to a longer range on the same charge. Planning your driving route in this manner uses a lot less energy, and by careful use of my rear view mirror I can make sure that this particular driving style is only used when it will not hold up the other drivers on the road. Heaven forbid that all of those people in their three-ton sport utility vehicles can’t make full use of that V8 in the residential neighborhoods!

You would be surprised how getting off of the main roads and using side streets can improve your commuting experience. You see a lot more, and the driving is more enjoyable. We all probably need to slow our lives down more often; an electric vehicle can help you do this.

My son Brian hurries out to the garage and into the car, and I am off to deliver him to a friend’s house before going to my office. Since completing this electric vehicle I have become very much a creature of habit. One of the rituals I undertake each morning without fail is to make sure that I reset the trip odometer to zero. That way I can track my exact distance from the plug in my garage to the plug that the research council has provided for me in their parking lot. It is really starting to get very silly, as I know the distance by heart now; it is precisely 5.4 km ( about 3.4 miles) one way. Maybe for some excitement I will stop for milk on the way home from work and the trip meter will register a new distance!

I often stop to think about how many of the details of each day’s commute I fuss over now. Ever since putting this homebuilt electric car on the road I spend a lot of time thinking about kilowatt-hours, volts, and amperes. I’ve had several batteries fail during various times this past year, and I have become acutely aware of this car’s needs.

Most people won’t want to get so involved with their cars, and when commercially available electric vehicles finally arrive in the showrooms, they’ll be as sophisticated and as easy to use as any of the modern gasoline-powered vehicles. They just won’t make any noise or emissions. Doesn’t sound too bad, does it?