Software update by Tesla to prevent battery fires may have reduced battery range

The US National Highway Traffic Safety Administration (NHTSA) is investigating a software update that e-car manufacturer Tesla shipped earlier this year. The update was intended to solve a potential problem associated with a few reported battery fires.

The software update appears to have decreased range of some vehicles

A few Tesla owners are even suing Tesla over the issue. The NHTSA received a 'defect petition" in September from a lawyer who represents some of the aggrieved Tesla owners.

A defect petition is filed

A recent article reports the filing: "A defect petition submitted to NHTSA by consumer attorney Edward Chen prompted the investigation. Chen filed the petition on behalf of Tesla owners, including his client David Rasmussen, after Tesla pushed over-the-air software updates to some vehicles, which reduced the range the electric cars could travel on a single charge, owners said.The petition complained that the software updates, which started in May 2019, were not an appropriate fix for batteries that could ignite in non-crash scenarios."

Chen claimed that Tesla used its software update to mask and cover-up potentially widespread and dangerous issues with batteries in some of their vehicles. Tesla has not immediately commented on the petition and investigation.

After investigation NHTSA has to issue a recall or publish findings

Another recent article explains how defect petitions are dealt with: "Defect petitions require more information than the typical complaints the NHTSA receives. Crucially, they also force the agency to act more conclusively: following the investigation, the NHTSA has to either issue a recall for cars affected by the alleged defects, or else publish its findings on the federal register explaining the decision not to."

Tesla's explanation of the update

Tesla issued the over-the-air update in May saying it was out of an abundance of caution after two fires in Asia the were highly publicized fires: " In April, an older Model S seemingly spontaneously combusted while sitting unused in a parking structure in Shanghai. The fire was caught by security cameras, and the footage quickly went viral. Tesla sent a team to investigate the fire, but has not released any findings. Just this week, another Model S caught fire in a parking lot in Hong Kong, shortly after the owner had charged the car. "

At the time, Tesla admitted that the update would change some setting in the battery management software governing charging and thermal controls of the cars. However, the company did not note that the changes could negatively effect the range of the cars on a single charge.

Chen wrote to the Department of Transportation and NHTSA: “For most owners, it was shortly discovered after updating their cars that the cars had suffered from a sudden and significant decrease in the amount of rated miles available."

There have been some reports of range drop-off following the update, but they are not widespread. The NHTSA will need to thoroughly investigate exactly what Tesla did in the update and determine how it might effect the battery.

Previously published in the Digital Journal