It indicates charging/discharging limit of the battery current. It represented as multiplier of Ah capacity of the battery.

1C (or C/1) means 1Ah battery can charge or discharge at 1 A.

0.5C (or C/2) means 1Ah battery can charge or discharge at 0.5 A.

2C means 1Ah battery can charge or discharge at 2 A.

Thus C-rating is a number which represents maximum charging/discharging current limit in the form of multiple times of Ah rating.

For application like Electric Vehicle, value of current discharge (current drawn by the motor, motor rated current) is generally higher than charging current (battery charging current), so we need to decide C-rating of battery based on rated motor current.

Example: Motor rated current is 10A, battery capacity is 5Ah. Then minimum C-rating must be 2C.

Motor rated current must be less than multiplication of C-rating and battery Ah capacity.

Smaller Ah rating battery needs higher C-rating for same power applications.

Lead acid battery of 1Ah with C10 or say C/10 or 0.1C, can charge or discharge 0.1 A.

C-rating is an important parameter of battery.

It indicates charging/discharging limit of the battery current. It represented as multiplier of Ah capacity of the battery.

1C (or C/1) means 1Ah battery can charge or discharge at 1 A.

0.5C (or C/2) means 1Ah battery can charge or discharge at 0.5 A.

2C means 1Ah battery can charge or discharge at 2 A.

Thus C-rating is a number which represents maximum charging/discharging current limit in the form of multiple times of Ah rating.

For application like Electric Vehicle, value of current discharge (current drawn by the motor, motor rated current) is generally higher than charging current (battery charging current), so we need to decide C-rating of battery based on rated motor current.

Example: Motor rated current is 10A, battery capacity is 5Ah. Then minimum C-rating must be 2C.

Motor rated current must be less than multiplication of C-rating and battery Ah capacity.

Smaller Ah rating battery needs higher C-rating for same power applications.

Lead acid battery of 1Ah with C10 or say C/10 or 0.1C, can charge or discharge 0.1 A.

Source: