New NTSB Tesla fatal crash report: Model S battery reignited twice after Florida crash
Video: Report suggests car system failures in deadly Tesla Model X crash.
A Tesla car's battery that ignited after a fatal crash reignited twice after it had been fully extinguished at the accident scene.
The US National Transportation Safety Board (NTSB) yesterday released its preliminary report into the Tesla Model S that crashed into a wall at high speed in Fort Lauderdale on May 8. The vehicle burst into flames, killing two teens and injuring a third.
The report notes that Fort Lauderdale Fire and Rescue Department found the Tesla "fully engulfed in flames" at the crash scene and extinguished it with 200 to 300 gallons of water and foam.
They also found portions of the lithium-ion battery had separated from the vehicle. These were not visibly on fire but responders applied water and foam to the debris.
When they were loading the car for removal, the Tesla's damaged lithium-ion battery reignited and was quickly extinguished, but then it reignited again as it arrived at the storage yard.
SEE: Tech and the future of transportation (ZDNet special report) | Download the report as a PDF (TechRepublic)
Something similar occurred to a Model X's battery following a fatal crash into a road barrier in Mountain View in March.
The 400-volt lithium-ion high-voltage battery was breached during the collision and a fire started after the crash.
The NTSB's report into that crash noted that after the fire had been extinguished and the car was taken to storage, the battery "emanated smoke and audible venting" but didn't ignite. However, five days later it reignited and had to be extinguished again.
The Model S, which was being driven by Barrett Riley, was traveling at 116mph three seconds before the collision, according to data the NTSB obtained from Tesla's restraints control module.
The crash occurred on a street with a 30mph speed limit. Riley lost control of the vehicle after attempting an overtake maneuver.
The vehicle erupted in flames after hitting the same wall in front of a residence twice, after which it re-entered the roadway and came to rest as it struck a metal light pole.
The NTSB is still gathering information about the systems and maintenance records of the Model S in search of more data sources that could potentially be recovered after the fire.
SEE: The new commute: How driverless cars, hyperloop, and drones will change our travel plans (TechRepublic cover story) | download the PDF version
It will also look at the procedures used to extinguish the battery fire and to remove and store the car after the crash.
According to Electrek, Tesla just last week rolled out a new speed-limiter feature in a software update and in release notes dedicated the feature to Riley, who was given the vehicle by his father.
The speed-limit mode allows the vehicle's maximum speed to be set between 50mph and 90mph, or 80km/h and 145 km/h.
A report by Sun-Sentinal in May quotes Riley's aunt saying his father had installed speed-control technology on his son's Model S to limit its maximum speed to 85mph.
He opted for the speed limit after Riley was booked in March for traveling at 112mph.
The Tesla Model S's battery reignited later at the storage yard.
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