Battery Capacity Testing

To carry out this test, use a high rate discharge tester, Starter, Alternator, Battery, Regulator, Electrical Tester (SABRE), in conjunction with 73 Digital Multimeter.
1. Turn SABRE OFF.
2. Turn the multimeter selector switch to the DB volt position.
3. Connect SABRE and multimeter positive test leads to the positive battery post and both negative test leads to the negative battery post. The multimeter clips must contact the battery posts and not the SABRE tester clips.
4. Adjust SABRE until the ammeter reads approximately half of the cold cranking amps of the battery.
5. With the ammeter reading the required load for 15 seconds, note the multimeter reading.

CAUTION: Avoid leaving the high discharge load on the battery for periods longer than 15 seconds.


6. If the multimeter reading is 9.6 volts at 21°C (70°F) or more, the battery has a good output capacity and will readily accept a charge, if required.
7. If the voltage reading obtained during the capacity test is below 9.6 volts at 21°C (70°F), and the battery is fully charged, the battery is defective and a new battery must be installed. If unsure about the battery's state of charge, charge the battery.
8. After the battery has been charged, repeat the capacity test. If the capacity test battery voltage is still less than 9.6 volts at 21°C (70°F), replace the battery. If the voltage is 9.6 volts at 21°C (70°F), the battery is satisfactory for service.
9. If the battery is found to be discharged only, check for a loose drive belt, loose electrical connection, charging system performance, and carry out battery drain testing. Drain Testing