EV charging

What Does 5C, 6C or 10C Charging Mean?

When a battery maker says 5C, 6C, 10C or 12C, the “C” is a rate relative to battery capacity. It is useful for comparing how aggressively a battery can accept or deliver power, but it is not the same as a guaranteed full-session charging speed.

Simple definition

Battery charging C-rate expresses charging power relative to battery capacity: in simplified terms, 1C corresponds to power equal to the battery's rated energy capacity in one hour, while higher C-rates indicate proportionally higher charging power.

The simple C-rate formula

For a simplified example, a 100 kWh battery charging at 1C corresponds to about 100 kW; 5C would correspond to about 500 kW. A 60 kWh battery at 5C corresponds to about 300 kW. Real batteries do not normally hold peak C-rate across the entire state-of-charge window.

Does 10C mean a full charge in six minutes?

Not automatically. Mathematically, a constant 10C rate would equal one-tenth of an hour, but real charging curves taper to protect the battery and because voltage, temperature and cell limits change with state of charge. Manufacturer C-rate figures are therefore best understood as capability claims tied to specific conditions and portions of the charging curve.

Why C-rate is suddenly everywhere

Chinese battery and vehicle makers are pushing the terminology into consumer marketing. BYD announced a 10C flash-charging battery with its 1000V Super e-Platform, while CATL has announced even higher peak C-rate figures in newer battery generations. This makes C-rate an important buyer term to understand.

What buyers should check instead of C-rate alone

  • 10–80% charging time.
  • Peak charging power in kW.
  • How long high power is sustained.
  • Battery capacity and temperature conditions.
  • Compatible charger voltage and current.

Sources

CarGlossary note:

Automotive terminology evolves quickly. We separate established standards from manufacturer-specific names and update pages as technologies move into production.