Ampere

In practical terms, the ampere is a measure of the amount of electric charge passing a point  per unit time. One ampere of Current represents one coulomb of electrical charge moving past a specific point in one second.

To calculate how many amps of power maybe used by a particular device, divide Watts by Voltage. Less is better than more in DC Voltage systems, as most boats have limited generation.

You may also read about cranking amps (CA). These measure the amount of Current a battery can provide at 0°C.

There are also cold cranking amps (CCA), which measure the amount of Current a battery provide at −18°C.