In October 1999, a 25-foot-long race car that looked like a gigantic pencil tore across the Bonneville Salt Flats in Utah. Reaching 254.229 miles per hour, the car, named White Lightning, shattered a U.S. speed record for electric cars.
Afterward, the pencil car was loaded onto a truck and driven home. It couldn't get there on its own because it was all out of energy. White Lightning doesn't run on a regular car battery; it runs on ordinary C-cell flashlight batteries--6,040 of them!
POWER SURGE
White Lightning is the brainchild of Ed Dempsey, a 64-year-old Huntington Beach (Calif.) native. Dempsey spent many years dreaming up the car, then seven months and $1.5 million building it.
Why did Dempsey choose household batteries, of all things, as a power source? "I did it to prevent overheating," Dempsey told Current Science.
When batteries are discharged rapidly, as White Lightning's are as it races down a track, they can get extremely hot. When batteries overheat, the chemicals inside them boil and leak out, draining the batteries' energy in a matter of seconds.
A flashlight battery has a very thin casing. When it starts to overheat, its outside heats up at the same rate as its inside. Because of that, a flashlight battery is easy to keep cool. Just blow cold air over it. Because an ordinary car battery has a thick casing, its outside and inside don't heat up at equal rates. Even if it is overheating inside, its outside might still be cool. Unlike the flashlight battery, the ordinary battery is harder to keep from overheating by blowing air over it.
AMPS AND VOLTS
Choosing what type of flashlight battery to use took more consideration, Dempsey said. Batteries generate both energy and power. A battery's energy, measured in amperes, determines how long it can supply electricity. A battery's power, measured in volts, is the amount of electricity that can be pulled from the battery in a short time. Because White Lightning needs to go fast but only for a short distance, Dempsey chose nickel metal-hydride (NiMH) batteries, which have a lot of power but not much energy.
Lead-acid batteries, which gasoline-powered cars and many of White Lightning's competitors use, provide more energy than power, giving the cars more endurance than speed.
CLEAR SKIES AHEAD
White Lightning has broken both U.S. and world records for fastest electric vehicle. But Dempsey wants White Lightning to do more than just set records. He hopes publicity about the car will help popularize electric cars.
So why doesn't everyone drive a flashlight battery car like White Lightning? For one thing, each of White Lightning's 6,040 batteries costs $5, so the car runs on more than $30,000 worth of batteries!
Fortunately, most of the electric cars on today's roadways are much less costly. They're also built for endurance rather than speed. They can go between 30 and 120 miles on one battery charge, with a top speed of 60 to 80 miles per hour.
Still, Dempsey predicts, electric vehicles won't replace gas-fueled cars until batteries can hold even more energy. Until then, he and driver Patrick Rummerfield will keep tinkering with White Lightning. Their next chance to break more records will happen this August, again at the Bonneville Salt Flats.
