C rating is a measure of the maximum continuous discharge rate of a battery, it is the number that indicates how many times the capacity of the battery can be discharged in one hour. It is usually expressed as a multiple of the battery's capacity, for example, a battery with a capacity of 2000mAh and a C rating of 20C can be safely discharged at a rate of 2000mAh x 20C = 40,000mA or 40A. A higher C rating means the battery can handle more current and therefore deliver more power to your RC car.

The C rating is an important factor to consider when choosing a battery for your RC car because it affects the performance and safety of the battery. A higher C rating allows the battery to deliver more power to the motor, which can increase the speed and acceleration of your RC car. However, it's important to note that a higher C rating also means that the battery will be drained faster and therefore need to be recharged more frequently.

It's also important to note that a higher C rating does not necessarily mean that a battery is better. Choosing a battery with a higher C rating than what your RC car needs can lead to overloading and overheating, which can damage the battery and even cause a fire hazard. Therefore, it's important to choose a C rating that is appropriate for your specific RC car and usage.

In addition to the C rating, other factors such as the voltage, capacity, and discharge rate of the battery are also important to consider when choosing the right battery for your RC car. It is always recommended to check the manufacturer's recommendations for the appropriate battery for your specific RC car model.