Tesla Supercharging Does Not Significantly Affect Battery Life, Study Reveals

It has long been believed in the industry that frequent DC fast charging for your Tesla or any EV is terrible for battery longevity. However, a new report from Recurrent, which analyzed data from over 12,500 Tesla vehicles in the US, clearly shows little to no difference in battery degradation between frequent and rare fast charging.

Recurrent studied fast charging on thousands of Tesla vehicles in the US to learn if the software and safety mechanisms in the battery management system (BMS) prevent damage to the battery. With Labor Day travel coming up, this is the perfect time to share what is fact and fiction when it comes to fast charging.

Your electric vehicle battery uses direct current (DC) power. However, the electricity from the grid (or from an outlet) is alternating current (AC). In-home charging, which is AC charging, the car’s onboard charger converts the AC electricity to DC and then sends it to the battery. The onboard charger has a built-in limit on how quickly it can do this. The maximum speed is usually around 11 kW, so AC charging can generally add 20-40 miles per hour, depending on the vehicle.

On the other hand, DC charging happens when the conversion to DC energy happens outside of the car. This is almost exclusively reserved for public charging stations and Tesla Superchargers. Since the electricity going into the car bypasses the onboard converter, it can refill the battery much faster. One of the biggest concerns with fast charging is that it can, theoretically, damage the battery by pushing too much energy into the battery too quickly. This would lead to irreparable, long-term range loss.

Will fast charging hurt my EV battery? The short answer is that occasional fast charging is fine. The study compared cars that fast charge at least 90% of the time to cars that fast charge less than 10% of the time. In other words, people who almost exclusively fast charge their car and people who rarely fast charge.

The results show no statistically significant difference in range degradation between Teslas that fast charge more than 90% of the time and those that fast charge less than 10% of the time.

Initial analysis by the team at Recurrent suggests that the study findings can be applied across Tesla models and other EV manufacturers. However, detailed research is being conducted on other popular vehicles Recurrent supports. In short, the robust thermal, voltage, and battery management systems that EV makers have invested in protect their batteries from damage with routine fast charger use.

Tesla specifically does an excellent job regulating power to and from the battery based on the temperature of the battery pack, its state of charge (charge percentage), and other environmental factors such as external temperature.

When is fast charging more likely to cause damage? There are several times when fast charging may impact your EV battery more. Avoid fast charging in extreme heat without preconditioning your battery. Preconditioning is when the car’s thermal management system pre-cools or heats the battery to accept a higher charge rate.

Typically, the battery will be preconditioned if you set your car’s navigation to a fast charge station. Similarly, precondition the battery before fast charging in extreme cold. Driving a bit before fast charging is often enough to warm up the battery or get to the fast charger using your car’s navigation. Avoid fast charging your EV at very low states or very high states of charge since battery resistance will be higher.

Overall, this study adds to the growing body of knowledge regarding EV battery longevity and charging practices. Nonetheless, being mindful of battery health during extreme temperatures is still encouraged.

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