Battery Capacity Test

To perform this test, use high rate discharge tester, Alternator, Regulator, Battery and Starter Tester (ARBST) in conjunction with 73 Digital Multimeter.
1. Turn ARBST OFF.
2. Turn 73 Digital Multimeter to the Direct Current (DC) volt position.
3. Connect ARBST and 73 Digital Multimeter positive test leads to the positive battery post and connect both negative test leads to the negative battery post.

NOTE: The 73 Digital Multimeter clips must contact the battery posts and not ARBST tester clips.

4. Adjust ARBST 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 73 Digital Multimeter reading. Avoid leaving the high discharge load on the battery for periods longer than 15 seconds.
6. If the 73 Digital 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) or more, and the battery is fully charged, the battery is defective and must be replaced. If unsure about the battery state of charge, charge the battery.
8. After the battery has been charged, repeat the Capacity Test. If the battery voltage is still less than 9.6 volts at 21°C (70°F), replace the battery. If the voltage is 9.6 volts or more at 21°C (70°F), the battery is satisfactory.
9. If the battery is found to be discharged only, check for a loose drive belt, loose electrical connections, and charging system performance. Perform Battery Drain Testing. Drain Test