Tesla Model S owners will receive upgraded charge adapters

After a garage fire in Irvine, Calif., in November of last year in which an overheated charging system for a Tesla Model S sedan was stated to possibly have been involved, Tesla will be sending out upgraded wall-charger adapters to all Tesla Model S owners.

This upgrade comes on the heels of an over-the-air software update for the charging system in the Model S sedan. Software version 5.8.4 would enable the charging system to automatically reduce the charging current by 25 percent if the system detects unexpected fluctuations in the input power, essentially slowing the charging current and reducing the heat created in any high-resistance connections if the car senses that the current is unsteady.

No people were hurt in the November 2013 garage fire, though it did damage the garage, its contents, and the car. The garage fire in question was investigated by Tesla, which reported that it had examined the scene of the fire and found that the cable was fine on the vehicle side, and that all the damage caused by the fire was on the wall side.

"Our inspection of the car and the battery made clear that neither were the source and were in fact functioning normally after the incident. In addition, a review of the car's logs showed that the battery had been charging normally, and there were no fluctuations in temperature or malfunctions within the battery or the charge electronics," the automaker said in a statement.

Tesla also reviewed the car's logs and stated that they were able to ascertain that the car had been charging normally and that there were no fluctuations in temperature with the battery or other parts of the charging system.

"We looked into the incident," Tesla spokeswoman Liz Jarvis-Shean said at the time. "We can say it absolutely was not the car, the battery or the charging electronics."

A contemporaneous report from the responding fire department did not actually state that the Tesla's charging system caused the fire, though it did implicate it in the following manner:

"The most probable cause of this fire is a high resistance connection at the wall socket or the Universal Mobile Connector from the Tesla charging system."

In deciding to provide all Model S owners with an adapter in addition to charging software upgrade 5.8.4, Tesla cautioned that a variety of factors like corrosion, inappropriate wiring or installation of electrical outlets, or physical damage to receptacles can all cause higher than normal electrical resistance when using the car's Universal Mobile Connector, and can cause excessive heating of the adapter. Tesla was also keen to point out that they did not believe that the improved wall adapter with a thermal fuse was required per se, but that they would provide it to new and existing customers free of charge within a few weeks.

By Jay Ramey