What is the required liquid level inside the battery?


Only distilled (preferred), deionized or reverse osmosis water should be used in flooded battery cells. Improper watering may cause internal cell damage. Test water to confirm a PH reading of 7 or less and no Total Dissolved Solids (TDS < 5 PPM).

NOTE: Do not add sulfuric acid to flooded battery cells during a normal top up. In the case of an accidental spill, premixed electrolyte (1.265 S.G.) may be used to refill cells.

CAUTION: Do not add water or electrolyte to cells before initial charging unless plates are exposed. If so, add distilled water until plates are submerged. Please contact Rolls Technical Support if you have any questions or concerns.

NOTE: If the battery cells require watering more than once every two (2) months the programmed charging voltages may be too high. Adjust and monitor accordingly. If a particular cell requires significantly more water than others this may be a sign of charge imbalance in the battery bank caused by resistance and/or cell failure. Typically, Series 4000 & 4500 models will require watering every 30-60 days. Series 5000 batteries generally require watering every 60-90 days as these models are designed with a higher electrolyte reserve allowing longer watering intervals. The frequency may vary considerably due to operating temperature, depth of discharge, cycle frequency and humidity.

For flooded model cell spacing reference information used in sizing watering systems, refer to the following Flooded Cell Spacing document.