C-Rate
Definition
Measure of charge or discharge current relative to battery capacity. 1C means the battery is fully discharged in 1 hour; 2C means 30 minutes.
Why It Matters
- Universal way to specify charge/discharge rates across capacities
- Cell specifications often given as max C-rate
- Higher C-rates generate more heat and reduce cycle life
- Practical limit often 3-5C continuous, 10-15C peak for high-power cells
Common Pitfalls
- Not accounting for capacity decrease at high C-rates
- Assuming symmetric charge/discharge C-rate limits
- Not drating C-rate capability at low temperature
- Ignoring C-rate effects on cycle life