Cold Cranking Amps (CCA): CCA measures the battery's ability to deliver power at 0 degrees Fahrenheit (-17.8 degrees Celsius) for 30 seconds while maintaining at least 7.2 volts. The higher the CCA rating, the more power the battery can deliver to start your engine in cold weather.
Reserve Capacity (RC): RC measures how long a fully charged battery can supply electrical power to your vehicle's accessories (such as the lights, radio, and air conditioner) without the engine running. It is expressed in minutes. The higher the RC rating, the longer the battery can power your accessories without needing a recharge.
In addition to CCA and RC, some car batteries may also be rated by their amp-hours (Ah) and voltage (V).
Amp-Hours (Ah): Ah measures the battery's capacity to store electricity. It is calculated by multiplying the current in amps (A) by the time in hours (h) that the battery can deliver that current. The higher the Ah rating, the more electricity the battery can store.
Voltage (V): V measures the electrical potential between the battery's positive and negative terminals. The voltage is typically 12 volts for most car batteries.
