Battery Hydrometer Displays Dark or Yellow Dot

Object Number: 405478  Size: DEFAULT
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  1. The battery has a built-in hydrometer (1). The hydrometer lens provides a visual indication of the condition of the electrolyte.
  2. Tap lightly on the lens and observe the built-in hydrometer (1).
  3. Under normal operation, one of three color conditions on the hydrometer (1) is possible:
    • Green ball visible (2). This condition indicates a sufficient state of electrolyte (5) charge (65 percent or above) for normal charging system operation.
    • Dark lens (3) (Green ball not visible) This condition indicates an insufficient state of electrolyte (5) charge (below 65 percent). Recharge the battery before further testing.
    • Clear lens (4) (Yellow lens) This condition indicates that the electrolyte (5) is low. The battery electrolyte (5) cannot be refilled. Replace the battery.
  4. A low electrolyte (5) level can be caused by any of the following conditions:
    • Prolonged charging
    • An excessive charge
    • A broken case
    • Excessive battery tipping
  5. When finding a battery in this condition it may indicate high charging voltages caused by a faulty charging system. The charging and electrical systems should be checked.
  6. If there is a cranking complaint, inspect for trouble in the charging or electrical systems.
  7. If a cranking complaint exists and is caused by the battery, the battery should be replaced.