On a battery, “MCA” signifies Marine Cranking Amps. It is a rating that indicates the amount of current, measured in amperes, a fully charged battery can deliver for 30 seconds at 0 degrees Fahrenheit (-17.8 degrees Celsius) while maintaining a voltage of at least 7.2 volts. As an example, a battery labeled with 800 MCA can supply 800 amperes under those specific conditions.
This rating is crucial for marine applications, where starting a cold engine reliably is paramount. The measurement reflects the battery’s ability to provide sufficient power to turn over the engine in cold weather conditions. Historically, this specification developed alongside the increasing need for reliable starting power in watercraft, influencing battery selection and design within the marine industry.