Hydrometer Check

1. GREEN DOT VISIBLE
^ Refer to "Load Test".Battery Load Test
2. GREEN DOT NOT VISIBLE (DARK DOT)
^ Charge battery to fully charged state, refer to "Battery Charging".
^ Battery is in a fully charged state (Green Dot Showing), refer to "Load Test". Battery Load Test
^ Battery does not come to a fully charged state in the recommended time of charging (Green Dot not Showing), refer to "Battery Replacement".
3. CLEAR OR YELLOW DOT
^ If the hydrometer is clear or light yellow, the battery is low on electrolyte, refer to "Visual Inspection". Visual Inspection - Battery
4. LOAD TEST

Battery Terminal Adapters:

Before proper load testing, the battery must be in a fully charged state to obtain an accurate test. Load testing requires the use of battery side terminal adapters GM P/N 12303040 or equivalent to ensure good connections.
1. Use J 39200 to measure voltage across the battery terminals. With all loads off, and the green dot showing in the hydrometer, voltage should be 12 volts or higher. Unless the battery has just been discharged (such as by a load test or cranking the engine), replace the battery if the voltage is below 12 volts.
2. With J 39200 still attached, connect a battery load tester across the battery terminals.
3. If the battery has been charging, apply a 300 ampere load for 15 seconds to remove the surface charge from the battery. Remove the load. (Do not complete this step if the battery has not been recently charged.)

Battery Temperature Vs. Voltage:

4. Wait 15 seconds to let the battery recover. Apply the specified load located on the battery label or listed in "Battery Specifications". Read the voltage after 15 seconds, then remove the load.
5. If the voltage does not drop below the minimum value, the battery is good and should be returned to service. The battery temperature must be estimated by feel and by the temperature the battery has been exposed to for the proceeding few hours.
6. If voltage drops below the minimum value listed, replace the battery.