Do Water and Electric Cars Mix? A Look at the Safety Standards

PHOTO CREDIT: JON WRIGHT / SOLAR HOME & BUSINESS JOURNAL
The EVs hitting the U.S. market later this year, such as the Nissan Leaf, above, will have sophisticated automatic shut-off and safety systems.
 

By Pamela Coyle
Coyle on Cars

Published July 17, 2010

We all remember parental warnings about mixing electricity and water. Those cautions are reinforced, at least in my case, by watching entirely too many accidental or homicidal death scenes on television that involve a small electric appliance and a bath, or in high-end settings, a hot tub.

Cars and water don’t mix well. I’ve managed to avoid driving through high floodwaters in both New Orleans and Nashville, but I’ve seen the results for those less fortunate. Inundated with cool water, hot engine blocks crack. The 12-volt electrical systems freak out. People get injured or killed – but by the water, not the electricity. And the carpet and upholstery never, ever recover.

PHOTO CREDIT: SOLAR HOME & BUSINESS JOURNAL
The battery pack shown in a cutaway diorama
of the Chevrolet Volt. Any loss of isolation
within the electrical system shuts it down.

The 2010 hurricane and flood season is upon us. The U.S. rollout of some high-profile EVs is nigh. And a question nags at me: What about the water?

An electric vehicle is not a toaster. Toasters, at least the ones we use at our house, do not have sophisticated automatic shut-off and safety systems, and EVs hitting the U.S. market later this year will. Keith Schultz, GM’s senior manager of Global Vehicle High Voltage Electric & Battery Safety, and Mark Perry, director of product planning for Nissan Americas, talked to me about electric power systems in the Volt and the Leaf, respectively.

The high-voltage wiring is under the car and not within the passenger cabin. In general, an impact automatically shuts down the high-voltage system that powers the car. Air bag deployment shuts it down. The battery pack itself is completely sealed. Any loss of isolation within the electrical system shuts it down. A manual shut-off exists for first responders who may worry that the juice is still flowing.

Both General Motors and Nissan are providing information and training to emergency personnel in their EV target markets. The Volt training begins next month in Chicago during the International Association of Fire Chiefs Fire-Rescue International Conference.

Although the Volt has a small internal combustion engine that keeps the battery charged longer, both it and the Leaf incorporate high-voltage power that is engineered differently than the familiar vehicle 12-volt batteries that power the lights, stereo and other auxiliary systems.

A jolt from a 12-volt can give you a bad buzz. An electric shock from a damaged high-voltage EV can kill, or can ignite stray gasoline. A regular car battery produces shocks because it is not a closed system and is grounded in the vehicle structure itself. In an EV, the electrical system is isolated and self-contained in its own circuit. “Any loss of isolation, the battery sucks down and the control system will open the main contactors and contain the energy in the battery pack,” Mr. Schultz says. “If there is a crash, sensors also instruct the computer to open main contactors.”

These cars also have manual electric system shut-offs. In the Volt, a module attached to the battery pack is pulled out and separated. Access to a similar manual disconnect in the Leaf is through a panel in the floor, under a piece of carpet.

Mr. Perry of Nissan describes it as “three-layer protection.” The charging port has similar safeguards. “If damage to the port, then no power,” he says. And all major EV manufacturers have agreed to use a standard plug port.

High-voltage wiring also looks different. It is orange. This is not an arbitrary designer choice. Because electric vehicles are, well, electric, they must conform to electrical industry standards for wiring, and those rules dictate orange wrapping for the high-voltage stuff.

Gas-electric hybrids already follow these rules and carry some mighty powerful battery packs, ranging from about 150 to more than 300 volts of direct current. The danger zone for DC power can be as low as 55 to 60 volts, compared to 110 volts for alternating current.

EMTs, paramedics and firefighters are trained to recognize orange as high voltage. Should they need to cut the wires, labels with helpful icons that include a red fire helmet and pliers point the way in the Volt. The cut points also are wrapped in bright yellow tape.

EVs will face the same federal standards for crash testing, and the manufacturers have put the battery packs through some special ordeals to test their integrity. At Nissan, for example, engineers have dumped the battery pack into swimming pools, frozen it and hit it with high-pressure hoses, Mr. Perry says.

Safety is not a frivolous concern, and countering consumer misperceptions and wariness about new EV technology is part of the industry’s challenge. “A lot of myths out there we are trying to dispel up front so we can get ahead of it,” Mr. Schultz says.

So the bad news is that floodwaters still can quickly consume a vehicle and its occupants. The medium news is that it doesn’t much matter how the vehicle is powered. The good news is that the weight and location of battery packs may give EVs an edge because they create a lower (and heavier) center of gravity but also permit ground clearance that is higher than a typical sedan and closer to that of an SUV.

And honestly, we drive around now in vehicles with internal combustion engines, which get really, really hot, and many gallons of highly flammable liquid. Cue up any episode of “Burn Notice” or the James Bond theme music, please.

Odds and Ends

Wherever Wheego. Wheego started taking orders for the full-speed Wheego LiFe on June 14 and the first cars will ship to U.S. customers in September. This generation of Wheego will be highway-ready and last about 100 miles on a charge; the Wheego Whip LSV is limited to roads with posted speed limits of 35 mph.

Wheego, based in Atlanta, took eight Whip LSVs to Bonnaroo in early June for the festival staff to use behind the scenes transporting themselves and the artists. With temperatures hitting 100 degrees in Manchester, Tenn., for this year’s party, the Whip’s air conditioning proved quite popular. And unlike golf carts, the Whip has a lock.

The General Services Administration in late June approved the Whip LSV for government contracts, allowing the company to sell the cars to federal agencies and U.S. military installations, where, as it happens, posted speed limits are 35 mph or less.

New digs, new states. It is no surprise that ECOtality Inc., the charging infrastructure folks, located its new headquarters in San Francisco. The Bay Area is an EV epicenter and California is expected to be the largest electric vehicle market in the U.S. The company’s offices for Innergy Power and the ECOtality Store will stay in their San Diego locations, and the offices in Seattle, Portland, Los Angeles, and Tennessee will stay put. ECOtality North America will continue in Phoenix.

On Thursday, the company added Dallas/Fort Worth and Houston to the EV Project, bringing the total to 16 cities in six states: Washington, Oregon, California, Arizona, Tennessee and Texas, plus the District of Columbia. Overall, The EV Project will include the manufacture and installation of more than 15,000 chargers in residential and public locations throughout the United States.

Volt ramps up. General Motors estimates annual production of 10,000 Volts in 2011, and 30,000 Volts in 2012. The company says Volts will be available in all 50 states 12 to 18 months after the initial retail launch. The first Volts will be sold in California; Washington, D.C.; Austin, Texas; and the New York City metropolitan area later in 2010. Dealerships in Michigan, New Jersey and Connecticut, plus the remaining Texas and New York markets, will be next up in the first quarter of 2011.

Chevy also announced on Wednesday it will warranty the Volt battery for eight years or 100,000 miles.

Blame it on gas. With relatively low summer gas prices, U.S. sales of hybrid cars fell by 17.5 percent in June, compared to June 2009. Overall car sales, however, increased 14 percent. The numbers, from hybridcars.com, suggest 2010 will be the third consecutive year of declining hybrid sales.

Pamela Coyle, a freelance writer and editor based in Nashville, Tenn., was an assistant city editor at The Times-Picayune in New Orleans during Hurricane Katrina and a member of the newspaper’s Pulitzer Prize-winning Katrina coverage team. Most recently, Ms. Coyle was an assistant city editor at The Tennessean in Nashville. She has a master's degree in the study of law from Yale University and is a regular contributor to EnergyBiz magazine. Contact her at pcoyle@sunpluggers.com.