Quick Answer
Noting specific gravity variations across cells is crucial for identifying potential issues, ensuring equal state of charge, and preventing battery degradation, which can lead to reduced performance, capacity loss, and even catastrophic failures.
Variations in Specific Gravity
The specific gravity of a battery cell is a measure of its density compared to distilled water. It is a critical indicator of the cell’s state of charge and health. A slight variation in specific gravity between cells can indicate a problem, such as a cell being overcharged, undercharged, or experiencing a loss of electrolyte due to sulfation or internal shorts.
Measuring and Monitoring Specific Gravity
To monitor specific gravity variations, use a hydrometer or a specific gravity tester, which is a simple and non-invasive method. For most deep cycle batteries, a variation of 0.005 to 0.01 points between cells is considered acceptable. However, if the variation exceeds 0.015 points, it is a cause for concern and warrants further investigation.
Correcting and Preventing Specific Gravity Variations
To correct specific gravity variations, identify and address the root cause, which may involve adjusting the charging or discharging schedule, checking for and correcting internal shorts, or replacing affected cells. To prevent specific gravity variations, ensure that all cells are at the same state of charge, keep the battery bank in a well-ventilated area, and avoid overcharging or deep discharging the batteries.
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