What Does 5C, 6C, 10C or 12C Charging Mean?

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 high-voltage fast-charging platform, while CATL has announced even higher peak C-rate figures in newer battery generations. On September 23, 2026, Geely also introduced a 12C battery alongside its 2.25 MW Smart Charge system. This makes C-rate an important buyer term to understand. See megawatt EV charging for the difference between battery C-rate and charger kW.

What does 12C charging mean?

In simplified terms, 12C means peak charging power equal to 12 times the battery's energy capacity. A 95 kWh pack at 12C corresponds to roughly 1,140 kW. This is a peak-rate relationship, not a promise that the pack will hold that power from 0% to 100%.

Geely's September 2026 Smart Charging launch makes 12C a production-facing buyer term: Geely says its Shendun Golden Battery supports a 12C peak rate and demonstrated 10–70% in 4 minutes 30 seconds and 10–97% in 8 minutes 40 seconds in Lynk & Co 10 and Zeekr 001 test vehicles. See our charger power vs car charging power guide for why the 2,250 kW station rating is a different number.

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.

Battery-health question:

See does ultra-fast charging damage EV batteries? for lithium plating, heat, BMS protection and Geely’s pulse-restoration claim.

Sources

CarGlossary note:

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