Tesla Recalls its Model S EV Chargers for Fires

Wanna be automaker Tesla’s technical troubles and safety issues continue.

In the latest Tesla recall, the fledgling car company has told the National Highway Traffic Safety Administration that it tried to push too much electricity too fast through its Model S EV charging system in order to decrease the recharging time. The result is a burned connector or in the worst case, electrical arcing, which leads to fires.

“Electrical resistance heating in the adapter or at the interface to the wall socket may lead to melting of the adapter, cord or wall receptacle, and possible electrical arcing that could lead to fire,” Tesla said in the required NHTSA safety defect filing.

It is not clear if Tesla complied with U.S. safety regulations requiring a recall within five days of a known defect since the awareness of the problem goes back to late 2012. In the lawyer written filing to NHTSA, Tesla says, “Since Model S deliveries began in earnest in late 2012, Tesla has received a very small percentage (2.7%) of returned UMCs (universal mobile connectors) that showed signs of internal damage only and that stopped vehicle charging. This was not a safety matter since damage was contained wholly within the UMC and resulted in cessation of power flow when the damage occurred – specifically, at the interface between the UMC and NEMA 14-50 adapter. In late 2013, Tesla became aware of several events that resulted in thermal damage external to the UMC. Based on this new information, the Company initiated an internal review of the UMC design, as well as the several external damage incidents, including a highly publicized event that took place in Irvine, California.”

Tesla has now issued a new software update to address the fires. This update allows the Model S onboard charging system to detect any unexpected fluctuations in the input power or higher resistance connections to the vehicle. If detected, the onboard charging system will automatically reduce the charging current by 25%. For example, this will reduce a 40-amp charge rate to 30 amps. Tesla did not say how much this increases the recharging time.