Summary
- Research shows that most EV batteries rarely fail over the typical lifespan of a vehicle
- Out Of Spec’s testing on a 250,000-mile Tesla Model S shows significant degradation in range and charging time
- Charging from 80-100% takes the longest due to the struggle of free electrons to find open spaces in the battery
- The Battery Management System needs to recalibrate and balance cells, impacting charging times
- Recommendations are to charge from 10-80% for better performance and faster charging, with EV batteries improving each year and not guaranteeing reliability beyond 200,000 miles
Article
The Reality of EV Battery Degradation
As research on EV battery longevity continues, there is growing optimism that battery degradation may not be as significant of a concern over the typical lifespan of electric vehicles. However, recent testing on a 250,000-mile Tesla Model S by Out Of Spec has provided some insights that temper these expectations. The testing revealed that the car’s range has significantly decreased over time, and the charging time has also increased, indicating possible battery degradation issues.
Charging Challenges with High-Mileage EVs
A recent 0-100% charging test on a high-mileage 2019 Tesla Model S showcased the challenges faced with aging EV batteries. The charging process took a total of 2 hours and 41 minutes, with the last hour primarily focused on getting the vehicle from 80-100%. This delay in charging can be attributed to the difficulty in filling batteries close to their full capacity, especially as they degrade over time.
Importance of Battery Management Systems
One key factor contributing to the prolonged charging time of the high-mileage Tesla Model S was the need for the Battery Management System to recalibrate and balance the cells. This process is essential for maintaining the health and efficiency of the battery, but it can become more challenging as the battery ages. Proper calibration and maintenance of these systems are crucial for optimizing the charging performance of EVs.
Optimal Charging Practices for EV Owners
To mitigate the effects of battery degradation and improve charging efficiency, EV owners are advised to avoid charging their vehicles to 100% capacity. Instead, charging between 10-80% is recommended as it represents the optimal charging curve for most road trips and daily use. While the charging time from 10-80% may still be slower for high-mileage EVs, it is a more practical and sustainable approach for maintaining battery health.
Road Trip Strategies for Aging EVs
For older EVs with reduced battery capacity, adopting smart road trip strategies can help optimize their performance. Making frequent, short stops at a low state of charge can be more beneficial than longer stops, as the peak charging rate tends to taper quickly with age. By planning routes with shorter charging intervals, EV owners can make the most of their vehicle’s limited battery capacity for extended journeys.
Future of EV Battery Technology
Despite the challenges highlighted by the testing of the 250,000-mile Tesla Model S, there is still room for optimism regarding the longevity of EV batteries. With advancements in battery technology and ongoing improvements in battery durability, newer EV models are likely to have more robust battery packs than their predecessors. While reliability beyond 200,000 miles may not be guaranteed, continuous innovation in EV battery technology holds promise for longer-lasting and more efficient electric vehicles in the future. For more information, contact the author at Mack.hogan@insideevs.com.
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