A Tesla Supercharger extension cord has recently gained attention as a possible solution to the charge port location issue encountered by non-Tesla electric cars (EVs). As the Tesla Supercharger network expands to include other EVs, variations in port location have created parking issues. While some people recommend utilizing extension cords as a solution, Tesla’s chief engineer, Wes Morrill, has expressed major concerns about the safety issues involved with this approach.
Why Supercharger Extension Cords are Being Considered
The expansion of Tesla’s Supercharger network to non-Tesla EVs presented an unanticipated challenge. Many EVs have charge ports in various locations, unlike Tesla vehicles, which have one on the driver’s side rear. It creates problematic parking situations where non-Tesla EVs frequently occupy two charging places.
To address this, some enthusiasts recommend using extension cords. These cords may allow non-Tesla EVs to approach the Supercharger more readily without parking awkwardly.
Safety Concerns Raised by Tesla’s Lead Engineer
Tesla’s Cybertruck chief engineer, Wes Morrill, has cautioned against utilizing extension cables at Superchargers. He identified various dangers with North American Charging Standard (NACS) extension cords. Morrill says these connections can cause overheating and short circuits in the DC power supply.
Morrill stated that he has witnessed numerous situations where extension cords caused cables to overheat, resulting in harmful conditions. This occurs because the extension turns off the safety function built into the Supercharger cables, which senses temperature and decreases power as needed. He said:
I would recommend AGAINST using an extension cord on a supercharger (or any DC charging station with a liquid cooled cable). Have seen multiple instances of the cable overheated and shorting DC +/-.
Impact of Losing Temperature Control
Supercharger cables’ most important safety aspect is their capacity to sense temperature. When the wires overheat, the Supercharger cuts power to avoid damage or accidents. However, this temperature control method does not function with extension cords.
Morrill said that adding an expansion increases the amount of heat and the number of connecting points, making overheating more likely. Controlling the temperature in an extension cord is practically impossible without liquid cooling, which is utilized in regular Supercharger cables.
“There’s a temperature measurement in the handle and the supercharger derates based on that temperature. With the extension cable that safety goes away. On top of adding an additional junction which generates heat making matters worse,” Morrill noted in a post on X.
Tesla’s Approach to Charging Safety
Tesla has always prioritized safety in its vehicles and charging infrastructures. As a result, the business has previously cautioned against utilizing some standard methods to alter charging performance. For example, Tesla has urged drivers not to use a wet towel on a NACS handle to get more power into the vehicle, which can cause overheating. The company’s engineers develop every component of the Supercharger system, including the wire length, to ensure maximum safety and reliability. Wire extension using an aftermarket extension cord may jeopardize this design and pose new hazards.
The Future of Supercharger Cables
Tesla is working on longer wires for the Supercharger V4 stalling. These longer wires would address the issue of non-Tesla EVs requiring additional reach without requiring an extension cord. However, the bulk of Supercharger stations continue to use V3 stalls, which do not offer the exact cable length flexibility.
While extension cords may be a practical solution for charging non-Tesla EVs at Superchargers, Tesla engineers know the potential safety issues. Overheating, loss of temperature control, and adding heat at junction points make using these cords a major risk. Tesla focuses on building safe and efficient charging systems; therefore, using extension cords will likely be discouraged.
