Battery Capacity Test

1. To perform this test use a high rate discharge tester, Alternator, Regulator, Battery and Starter Tester (ARBST) in conjunction with 73 Digital Multimeter.
2. Turn ARBST OFF.
3. Turn the 73 Digital Multimeter selector switch to the DV volt position.
4. Connector ARBST and 73 Digital Multimeter positive test leads to the positive battery terminal and both negative test leads to the negative battery terminal. The 73 Digital Multimeter clips must contact the battery terminal and not the tester clips. Unless this is done, the actual battery terminal voltage will not be indicated.
5. Turn the load control knob in a clockwise direction until the ammeter reads approximately half the cold cranking amps of the battery.
6. With the ammeter reading the required load for 15 seconds, note the multimeter reading. Avoid leaving the high discharge load on the battery for periods longer than 15 seconds.
7. If 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.
8. 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 damaged and a new one must be installed. If unsure about the battery's state of charge, charge the battery.
9. 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), install a new battery. If the voltage is 9.6 or more at 21°C (70°F), the battery is OK.
10. If the battery is found to be discharged only, check for a loose drive belt, loose electrical connection, charging system performance, and perform battery drain testing. Drain Testing