A series of three fires in five weeks has prompted a federal investigation into the Tesla Model S. In a blog post yesterday, the luxury electric car company’s CEO and Chairman Elon Musk said Tesla requested the National Highway Traffic Safety Administration to investigate the undercarriage shield that protects the battery packs.
NHTSA has a different take. A spokesperson told the Chicago Tribune that it notified the automaker of its plans to open a formal investigation and requested their cooperation. The automaker agreed.
Either way, NHTSA is investigating the risks associated with undercarriage strikes on the 2013 Tesla Model S.
All three fires happened at highway speeds. The fire in Merida, Mexico resulted from a driver hitting a roundabout at nearly 100 mph, sending the 4,600 pound car airborne before it sheared a concrete wall, then broke through the wall, and slammed into a tree.
In the domestic fires in Washington on October 1 and again in Tennessee in early November, the drivers of the Model S hit a piece of road debris in the highway. In Washington, it was a hunk of metal from a truck; in Tennessee it was a large trailer hitch. In both cases the technologically-advanced car, which can cost between $70,000 to $120,000, warned the driver that something was wrong, indicating to pull over before power was shut down.
In all three cases, the drivers walked away and said they anticipated the delivery of their next Model S.
The NHTSA preliminary evaluation states: “The resulting impact damage to the propulsion battery tray initiated thermal runaway. In each incident, the vehicle’s battery monitoring system provided escalating visible and audible warnings, allowing the driver to execute a controlled stop and exit the vehicle before the battery emitted smoke and fire.”
An investigation can lead to a recall. Tesla ordered a recall earlier in the year for 1,228 Model S with a minor seat bracket issue.
The thermal runaway investigation will look at an estimated 13,108 Model S sold domestically.
Fires in electric car batteries have been acutely reported, as is common with the technology of any nascent industry. The Tesla coverage has been overblown, according to Musk, and, along with missed analysts' forecasts, has made Tesla’s stock price drop 38 percent from a high of $193 in late September to $120 this morning.
Earlier in the year the Model S earned a 5-star safety rating from NTHSA in every category.
Based on the average of 152,300 automobile fires a year, according to the National Fire Protection Association, Musk estimates that you are four and half times more likely to experience fire in a gas car. Since a gas tank is ten times more combustible than a battery pack, death and serious injury is much more likely in a gas car than in a Model S, Musk says.
Tesla voluntarily issued a three-part response to the Model S investigation.
*The air suspension, which will get an over-the-air software update, will have greater ground clearance. This might result in a less aerodynamic ride but should also reduce the chances of underbody impact damage.
*If NHTSA finds a material defect, Tesla will “apply that change to new cars and offer it as a free retrofit on all existing cars.”
*Tesla is amending its warranty to include damage due to fire, even if due to driver error, “to reinforce how strongly we feel about the low risk of our fire in our cars.” The base warranty is 4 years or 50,000 miles. The largest battery, 85 kWh, is covered for 8 years and unlimited miles.
The underlying issue contributing to Musk’s defensive stance is the misrepresentation of the Model S and electric cars in general as unsafe.
NHTSA investigated the plug-in hybrid Chevy Volt in late 2011 after one model caught fire three weeks after an accident. NHTSA did not demand a recall, instead issuing protocol to disconnect the battery after an accident until it can be checked for damage. Modifications made by GM sufficed. The report concluded: “NHTSA does not believe that electric vehicles pose a greater risk of fire than gasoline-powered vehicles.”
NHTSA did not investigate the first Tesla incident in Washington, deeming it an accident.
“If a false perception about the safety of electric cars is allowed to liner, it will delay the advent of sustainable transport and increase the risk of global climate change,” Musk writes. “That cannot be allowed to happen.”