To minimize battery degradation when using DC fast chargers, it is advisable to limit their frequency and prefer slower charging methods when possible, although moderate DC fast charging is generally not highly damaging.
Impact of DC Fast Charging on Battery Degradation
- Slightly higher degradation with frequent fast charging: Research from the Idaho National Laboratory showed that after 50,000 miles, Nissan Leafs charged only with Level 2 chargers lost about 24.5% of battery capacity, while those using Level 3 DC fast chargers lost about 27%, indicating a small increase in degradation (about 2.5%) associated with fast charging.
- Frequency matters: Data from over 10,000 EVs suggests that frequent use of DC fast charging (defined as more than 3 times per month) accelerates battery degradation significantly, especially in hot climates. Occasional use (0-3 times per month) has a much smaller impact.
- Heat is the main factor: The primary reason fast charging accelerates degradation is the heat generated by high charging currents, which strains lithium-ion cells. High temperatures accelerate battery wear more than the charging speed itself. Most modern EVs have thermal management to mitigate this risk, but prolonged or frequent exposure to fast charging can still cause increased wear.
- Voltage and current stress: Fast charging can cause voltage imbalances and increased wear on battery cells, contributing to capacity loss over time.
Recommendations to Minimize Battery Degradation
- Use DC fast chargers sparingly: Limit DC fast charging to occasional use, ideally less than 3 times per month, to keep battery degradation minimal.
- Prefer Level 2 AC charging for routine use: Level 2 chargers are gentler on the battery and have only a negligible difference in degradation compared to Level 1 slow charging, making them ideal for daily charging needs.
- Manage temperature exposure: Avoid fast charging in very hot climates or when the battery is already hot. Take advantage of built-in battery thermal management systems and try not to fast charge immediately after heavy driving or in direct sunlight.
- Avoid keeping the battery at 100% state of charge for prolonged periods: A high state of charge combined with fast charging can increase stress on the battery.
Summary
While DC fast charging accelerates battery degradation slightly compared to slower charging types, occasional use (around 0-3 times per month) will have a minimal impact on battery lifespan. Frequent use (3+ times per month), especially in hot climates, significantly increases degradation risk. To minimize battery wear, reserve DC fast charging for situations where rapid recharge is necessary and rely on Level 2 charging for everyday use.
This approach balances convenience with battery longevity, leveraging modern EV thermal management to reduce damage while maintaining practicality.
Original article by NenPower, If reposted, please credit the source: https://nenpower.com/blog/how-often-should-i-use-dc-fast-chargers-to-minimize-battery-degradation/
