EV battery degradation or capacity loss over time

Symptoms

• Maximum range at full charge is noticeably lower than when the car was new
• Change happened gradually over months or years
• Battery health percentage (if shown) has decreased slowly over time
• Car otherwise drives and charges normally

Likely causes

• CommonNormal gradual battery agingAll lithium-ion batteries lose some capacity over time and charge cycles, typically a small percentage per year.
• PossibleFrequent fast charging or charging to 100% regularlyThese habits can accelerate degradation slightly more than moderate charging habits.
• PossibleExtended exposure to extreme heatConsistently hot climates or frequent hot-weather fast charging can speed up capacity loss.
• Less commonA battery fault causing unusually rapid degradationUncommonly, a specific defect or cell failure can cause faster-than-normal capacity loss.

What to do

1. Check if your car or its app shows a battery health or state-of-health percentage, and note it over time.
2. Compare your car's degradation rate to typical published figures for your model, which most manufacturers or owner communities can provide.
3. Consider charging to 80–90% for daily use and reserving 100% charges for trips, and using fast charging less frequently, to slow future degradation.
4. Note whether the drop was gradual over years (typical) or sudden over weeks (atypical and worth investigating).
5. Check whether your battery is still under its manufacturer warranty, which usually covers excessive degradation for a set number of years or miles.
6. If degradation seems much faster than typical for your model, have the battery evaluated.

Tools and parts

When to call a pro

If degradation is faster than typical for your model or you're within the battery warranty period, have a dealer evaluate it for a possible warranty claim.

Safety