Battery Hydrometer Displays Dark or Yellow Dot

Molded into the top of the maintenance-free battery is a built-in temperature compensated hydrometer. Ensure that the battery top is clean when observing the hydrometer. Use a flashlight in order to observe the hydrometer in poorly lit areas. Do not produce any sparks. Use this hydrometer with the following diagnostic procedure.

Under normal operation, 1 of the following 3 indications will be observed:




1. The green dot is visible (A).
- Any green appearance in the hydrometer is interpreted as a green dot.
- The green dot means the battery is at least 65 percent charged and is ready for testing. Refer to Battery Not Operating Properly. Battery Not Operating Properly
2. When the green dot can not be seen (B). The charging is below 65 percent.
- If there is a poor cranking comment, refer to Generator Not Operating Properly Generator Not Operating Properly for further testing.
- In order to Inspect the charging system for excessive draw, refer to Battery Electrical Drain/Parasitic Load. Battery Electrical Drain/Parasitic Load Test
3. The dot appears clear or light yellow (C).
- A diagnosis can not be made at this fluid level.
- A clear or light yellow dot means that the fluid level is below the bottom of the hydrometer.
The following can cause a low fluid condition:
- Overcharging
- A cracked battery case
- Tipping the battery

A battery found with a low fluid condition can indicate a high charging voltage, caused by a faulty charging system. The charging system must be checked for specified output. The electrical system must be tested for a parasitic drain. Refer to Charging System Check. Component Tests and General Diagnostics

Replace the battery when there is a yellow or clear hydrometer along with a cranking comment. Refer to Battery Replacement (Left Battery) or Battery Replacement (Right Battery, Gas Engine).