Question 1

Why does charging slow down above 80%?

Accepted Answer

Above ~80% SoC, the BMS reduces charging current to prevent lithium plating and overheating. The voltage difference between charger and battery narrows, naturally reducing current flow. This CV (constant voltage) phase protects battery longevity but significantly increases time for the last 20%.

Question 2

Does fast charging damage the battery?

Accepted Answer

Frequent DC fast charging generates more heat and can accelerate degradation compared to Level 2 charging. Studies show 10-15% additional capacity loss over 8 years with predominant fast charging. Modern EVs with active thermal management and battery preconditioning mitigate most of this impact.