Built-In Hydrometer

A built-in temperature compensation hydrometer is molded into the top of the maintenance free battery. When observing the hydrometer, make sure the battery top is clean. Use a light in poorly-lit areas.

Under normal operating conditions, on of three indications can be observed.




^ Any green appearance in the hydrometer is interpreted as a green dot (1). This means the battery is ready for testing. Refer to Battery Not Operating Properly.
^ A dark dot is visible (2). The green dot is not visible.
- If the green dot is not visible and there is a complaint about cranking, charge the battery.
- Check the output of the charging system.
- Check the electrical system for excessive draws. Refer to Battery (Parasitic) Load Test.
^ A clear or yellow dot (3) means that electrolyte level is below the bottom of the hydrometer and is too low for diagnosis. The yellow dot may have been caused by one of the following conditions:
- Excessive or prolonged charging
- A broken case
- Excessive tipping

When you find a battery in this condition, this may indicate high charging voltages caused my a faulty charging system. Because of this, the charging and electrical system must be checked. Refer to Battery Hydrometer Displays Yellow Dot.

Replace the battery if a cranking complaint exists, and the battery has a yellow or clear hydrometer.