If there is not obvious physical damage, check electrolyte level. If level is above the top of the plates in all cells, take a hydrometer reading of each cell. Specific Gravity Test
The battery specific gravity indicates the battery state of charge. The specific gravity is the weight of a liquid compared to the weight of an equal volume of water. The specific gravity of chemically pure water at 80 degree F. is ONE, (1.000). The weight of sulphuric acid is 1.400 specific gravity. Acid is then mixed with water to form a solution called electrolite. The weight of electrolite is approximently 1.280 specific gravity. As a battery becomes discharged, a portion of the acid in the solution soaks into the plates. This leaves the solution with a weaker acid content and consequently in a weaker state of specific gravity. When the battery is recharged, the acid is driven from the plates back into the solu tion, restoring the solution and the specific gravity to full strength. Therefore the higher the reading the higher the state of charge. Use a hydrometer to determine the specific gravity of the electrolyte solution. If the state of charge is low, the hydrometer will read low. If the state of charge is high, the hydrometer will read high. Specific Gravity Test Specific Gravity
1.260 - 1.280 1.230 - 1.250 1.200 - 1.220 1.170 - 1.190 1.140 - 1.160 1.110 - 1.130
State of Charge
100% charged 75% charged 50% charged 25% charged Very Weak Discharged
Three Minute Charge Test
Test a battery that is less than fully charged with a fast battery charger and a three minute charge test. Use a fast battery charger in conjunction with the V.O.M. for this test. Fast charge the battery three minutes at not more than 40 amps for a 12-volt battery and 74 amps for a 6-volt battery. With the charger in operation, observe the voltage of the battery. If the voltage exceeds 15.5 volts for a 12-volt battery, or 7.75 volts for a 6-volt battery, the battery is worn Copyrighted Material Intended for CLARK dealers only Do not sell or distribute
IC 103 page 7
