A recent study conducted by the Department of Energy's Vehicle Technologies Office sheds light on significant differences in electric vehicle (EV) charging behavior at paid and free DC fast charging stations in the United States. The analysis, based on over 2.3 million charging sessions at non-Tesla DC charging stations from June 2020 to June 2023, indicates that EV drivers tend to spend nearly twice as much time at free DC fast chargers compared to paid ones.
According to the report, drivers at free DC fast chargers spend an average of 78 minutes per session, gaining 40.7 kilowatt-hours of energy. In contrast, at paid DC fast chargers, the average session time is 42 minutes, with drivers receiving 22 kilowatt-hours of energy. The study highlights the prevalent practice of using free charging stations for extended periods, potentially impacting overall charging infrastructure availability and raising concerns about long-term battery health due to exclusive reliance on fast charging.
While “free” DC fast charging is often offered as a perk with certain EV models, the study suggests that the perceived benefit can lead to challenges such as extended wait times and potential damage to batteries. The findings indicate that drivers at paid charging stations tend to optimize their usage, avoiding unnecessary charging beyond what is needed for reaching the next charging point or home.
The study does not include data from the Tesla Supercharging network, but it emphasizes the importance of responsible charging behavior, particularly when utilizing free charging programs. The analysis encourages EV users to use free charging opportunities judiciously, considering factors such as charging time, frequency, and overall charging needs. The data underscores the need for continued research and awareness regarding the evolving dynamics of EV charging patterns.
DC Fast Charging Statistics (June 30, 2020, to June 30, 2023):
- Free Sessions (957,265): 40.7 kWh per session, 78 minutes per session
- Paid Sessions (1,412,050): 22.0 kWh per session, 42 minutes per session
- Total Sessions (2,369,315): 29.4 kWh per session, 54 minutes per session Source: Energetics, EVWATTS Dashboard
*Note: The study is based on a self-selected set of EV owners nationwide and does not include Tesla's Supercharger network charging sessions.