Driving Your Electric Vehicle

part is very similar to the experience of a lifelong stick-shift driver who drives an automatic transmission vehicle for the first time. As for the maintenance, there’s a whole lot less to do, but it has to be done conscientiously. Let’s take a closer look at each area.

Driving Your Electric Vehicle

Your EV conversion may still look like its internal combustion engine ancestor, but it drives very differently. Here’s a short list of reminders:

Starting

Starting an electric vehicle conversion is a little bit of a science. There’s no need to use the clutch on startup because the motor’s not turning when your foot is off the pedal. On the other hand, there is a very definite need to have it in gear because you always want to start your series DC motor with a load on it so it doesn’t run away to high RPM and hurt itself. If you forget and accidentally leave the clutch in (or the transmission in neutral), back off immediately when you hear the electric motor winding up. The best analysis I have heard is that if your electric vehicle conversion is a lighter package (not a performance-based controller and heavy-duty motor) you can start the car in second gear without a problem since the torque of an electric motor will push the RPM (such as the Ford Ranger discussed in Chapter 10). Whereas the higher performance vehicles (such as the Porsche discussed in Chapter 10) can easily be started in fourth gear since the vehicles motor, controller, and batteries will have the necessary voltage requirements to accelerate from 0 to 60 in 4 to 6 seconds.

Shifting

If you do city driving, you’ll wind up mostly using the first two gears. The lower the gear, the better your range, so use the lowest gear possible at any given speed. However, if you do highway driving, expect to shift gears higher.

Economical Driving

If you keep an eye on your ammeter while driving, you’ll soon learn the most economical way to drive, shift gears, and brake. For maximum range, the objective is to use the least current at all times. You’ll immediately notice the difference in drag racing and going up hills—either alter your driving habits or plan on recharging more frequently.

Coasting

If you don’t have regeneration, coasting in an EV is unlike anything you’ve ever encountered in your internal combustion engine vehicle—there’s no engine compression to slow you down. You need to learn how to explain how to correctly “pulse” and when. I have ridden with drivers who floor it for three seconds, then coast, floor it, and coast. Heavy pulsing is not good for the vehicle and wastes energy. In most driving, a steady foot is better. Light pulsing is only an advantage when little power is needed.

Regeneration

Regenerative braking is a mechanism that reduces vehicle speed by converting some of its kinetic energy into another useful form of energy. This captured energy is then stored for future use or fed back into a power system for use by other vehicles.

For example, electrical regenerative brakes in an electric railway vehicles feed the generated electricity back into the supply system. In battery electric and hybrid electric

vehicles, the energy is stored in a battery or bank of capacitors for later use. Other forms of energy storage which may be used include compressed air and flywheels.

Many now have experienced coasting in a hybrid electric car. As with a hybrid and by definition, an EV is designed to be as frictionless as possible, so take advantage of this great characteristic. Learn to pulse your accelerator and coast to the next light or to the vehicle ahead of you in traffic.

Hybrid electric car owners (especially NYC taxi owners) understand this concept. When you accelerate, you do not need to floor it and then coast. You can slowly step on the accelerator and then take your foot off of the accelerator to coast. When you coast, you use the regenerative braking. It is much smoother and a more efficient use of the vehicle since it is moving forward and charging at the same time. While there are plenty of people who own converted EVs who like to floor it and coast, regeneration can be a very big help in most stop-and-go driving.

Determining Range

Use the battery voltmeter as a fuel gauge in conjunction with the odometer to tell you how far your batteries can take you. Tape a note to your dashboard or use a notebook to keep track of the elapsed mileage between full charges and voltmeter reading (for example, the voltmeter reading was x after you drove y miles) and you’ll quickly get an idea of the pattern. Keep in mind that your battery pack will not reach its peak range until you’ve deep-cycled it a few times.

Running Out of Power

Before you totally run out of power, get off the road! If you totally run out of power and cannot find an electrical outlet, turn off your key switch and allow your batteries to rest for 20 to 30 minutes (shut down everything else electrical at this time also). Amazingly, you’ll find extra energy in the batteries that may just be enough to take you to the power outlet you need. The convenience of an onboard charger is welcomed most of all in this particular circumstance. It is not good to be stuck in the middle of the busy freeway without power. You should understand that there is a significant power loss just before the no power condition. You should also know that a full discharge greatly shortens battery life.

Regular Driving

(Please note the equations are based on $4.50 per gallon. See Preface for more details.) Drive your EV regularly—several times a week. Remember, the chemical clock inside your lead-acid batteries is ticking whether you use them or not, so use them. Better yet, think of how much money you are saving by using your EV. The 20 6-volt 220-AH capacity batteries gave Jim Harris’ 1987 Ford Ranger conversion of Chapter 10 an onboard capacity of 26.6 kWh (220 AH 3 120 volts).

If Jim got a 60-mile range out of one charge, his average energy use would be 0.44 kWh/mi (26.6 kWh/60 mi). At an average of $0.15 per kWh, that works out to be 6.6 cents per mile (0.44 kWh/mi 3 $0.15 per kWh).

If you compare that with gasoline at $4.50 per gallon and a typical 25 mpg for the internal combustion engine pickup before conversion, that works out to 18 cents per mile (1/25 gal/mi 3 $4.50 per gal). That’s almost a three-to-one savings—take advantage of it. (Note: When we updated this to 2008 prices, the price ratio was better for electric vehicles versus the 1993 ratio that held steady for the past 50 years!)