Quick Answer
A flooded lead-acid battery typically requires watering when the electrolyte level falls below 1/4 inch below the top of the plates, and the specific gravity reading drops below 1.260.
Visual Inspection
Perform a visual inspection of the battery to identify signs of low electrolyte levels. Look for exposed plates, a low electrolyte level, or signs of drying out around the terminals. Check the battery’s state of charge using a hydrometer or specific gravity meter. If the level is below 1/4 inch, it’s time to add water.
Measuring Specific Gravity
Use a hydrometer or specific gravity meter to measure the electrolyte’s specific gravity. A reading below 1.260 typically indicates that the battery needs to be watered. It’s essential to measure the specific gravity at multiple points to ensure accurate readings. When adding water, mix it with a small amount of the existing electrolyte to prevent dilution.
Adding Water and Recharging
When watering a flooded lead-acid battery, add distilled water to the cells, making sure not to overfill. The recommended water-to-electrolyte ratio is around 1:7 (water to electrolyte). After watering, recharge the battery to its recommended voltage and charge state. This will help to equalize the electrolyte levels and prevent damage to the plates.
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