Rolls deep cycle lead acid batteries contains electrolyte with varying concentrations of water and acid (1.265, 1.250). A battery resting idle for long periods of time will often result in a separation of water and acid into distinct layers. The water remains at to the top and the acid sinking to the bottom of the cell. This difference in acid concentration can lead to greater corrosion of the bottom half of the plates and possible cell failure.
To prevent stratification, frequent charging and discharging is recommended to maintain a proper mix of electrolyte.