Deep-cycle batteries are most commonly used to run accessories or additional features in vehicles, motorhomes and caravans. They’re separate from the batteries we fit to start your car and are designed to be discharged over many cycles (discharged and recharged is equal to one cycle) without adversely affecting the battery’s life. Deep-cycle batteries generally have thicker plates to reduce plate buckling and improve battery life. Some types of deep-cycle batteries can be used in marine vessels and jet-skis. They are measured in Amps.