NHTSA Rejects Tesla Battery Management Software Investigation

NHTSA Denies Petition Regarding Tesla Battery Management Software

The National Highway Traffic and Safety Administration (NHTSA) has declined a 2019 request to initiate a formal inquiry into Tesla’s battery management software. The petition alleged a flawed over-the-air update contributed to fires occurring in five vehicles.

Reasons for Denial

A key factor in the agency’s decision not to proceed with a formal investigation was the geographical location of the majority of reported incidents. Most of these events transpired outside of the United States, as detailed in a document released by NHTSA.

Review of Complaints

NHTSA’s evaluation encompassed a review of 59 complaints from a total population of 61,781 Model S and Model X vehicles manufactured between 2012 and 2019, as outlined in the petition. The analysis revealed that 52 complaints centered on diminished battery capacity, while the remaining seven reported slower charging rates following the software update.

Vehicle log data indicated that voltage limiting firmware was active in 58% of the cases examined. However, subsequent software releases partially or fully restored battery capacity in affected vehicles, according to the report’s summary.

Analysis of Fire Incidents

The agency determined that a specific combination of circumstances led to two fires in China during 2019. These vehicles had recently undergone fast-charging, possessed a high battery charge level, and were parked with their battery cooling systems deactivated. Furthermore, both vehicles exhibited a history of demanding operational use.

Industry Perspective on Fire Frequency

Individuals with expertise in Tesla’s battery management systems suggest that a widespread software defect would likely manifest in a significantly higher number of fire incidents than just five. They posit that isolated cases are more likely attributable to manufacturing flaws or physical damage sustained during operation.

Specifically, subjecting vehicles to high stress shortly after Supercharging was identified as a potential contributing factor, a scenario reportedly more prevalent in China where the fires occurred.

U.S. and German Fire Incident Details

Two additional fires occurred within the United States. One involved a vehicle with no prior Supercharging history and occurred while the vehicle was in motion. The other could not be directly linked to the high-voltage battery system.

The fifth fire took place in Germany, involving a vehicle that had remained parked for an extended duration with a low battery charge.

NHTSA’s Concluding Statement

“Considering the lack of incidents in the United States involving fast charging, and the absence of similar incidents globally since May 2019, it is improbable that an order for notification and remedy of a safety-related defect would be issued should an investigation be opened based on this petition,” the agency stated in its final assessment.

“Therefore, after careful consideration of the information presented and the potential safety risks, the petition is denied.”

Future Considerations

Despite denying the current petition, the report affirmed that NHTSA would revisit the matter and take appropriate action if future findings revealed safety-related defects.

Ongoing Autopilot Investigation

Separately, NHTSA is actively pursuing an investigation into Tesla’s Autopilot software. This investigation stems from incidents where vehicles utilizing the advanced driver-assistance system collided with 12 stationary first responder vehicles displaying flashing lights, resulting in 17 injuries and one fatality since 2018.

Tesla is required to submit comprehensive Autopilot data by October 22nd, or face potential fines reaching $115 million. However, this amount is considered relatively minor given the company’s substantial second-quarter net income of $1.14 billion.