Deep-cycle batteries typically feature thick plates with a high-ensity active material.The thick battery plates allow for reserve energy to be stored deep within the battery plate and released during slow discharge such as trolling or electronic instrument use. The high-density active material remains within the batteries'plate/grid structure longer, resisting the normal degradation found in cycling conditions.They are typically used where the battery is discharged to great extent and then recharged. Deep Cycle refers to applications that typically discharge 60 to 70% or more of the battery capa city. An automotive battery is an SLI battery (Starting,Lighting & lgnition.)Its plates are designed to deliver maximum power for a short duration. Starting an engine typically discharges an SLI battery 3% or less. When an SLIbattery is used in a deepcycle application or in a vehicle with heavy accessory loads,the battery life will be sh ortened proportionally to how deeply and freque ntly it is discharged. The Fullriver Deep Cycle battery uses a different chemistry for the plates'active paste material,and a slightly stronger acid. This chemistry allows for a much longer life in deep cycle applications with only a slight reduction in maximum power output.