EV battery degradation: how much capacity do you lose over time?

What is battery degradation?

Every lithium-ion battery loses a small amount of its maximum capacity with each charge cycle. This is normal and expected. The practical effect is that after several years of use, your EV may have a slightly shorter range than when new. The question is how much capacity is lost, and how quickly.

What the data shows

Real-world data from tens of thousands of EVs suggests that most modern batteries degrade to around 90 to 92 percent of their original capacity after the first 100,000 km. The degradation rate slows significantly after the first year. A car that loses 8 percent capacity in year one might lose only 1 to 2 percent per year thereafter.

Factors that accelerate degradation

• Frequent DC fast charging (occasional use is fine; daily reliance accelerates wear)
• Regularly charging to 100% or discharging to near 0%
• Leaving the battery at high charge state in hot climates for extended periods
• Extreme temperature exposure (very hot or very cold)

Manufacturer warranties

Most major EV manufacturers warrant the battery to retain at least 70 to 80 percent capacity for 8 years or 160,000 km, whichever comes first. Tesla, Hyundai, Kia, and BMW all offer 8-year/160,000 km battery warranties. If degradation drops below the warranty threshold, the manufacturer is obligated to repair or replace the battery.

Impact on running costs

Moderate degradation rarely affects running costs meaningfully. Losing 10 percent capacity does not mean using 10 percent more electricity — it means you have less range before needing to charge. Your per-kilometre energy consumption (kWh/100km) remains largely unchanged. The practical impact is slightly more frequent charging stops on long trips.