If the reading is lower than 12. 2 volts, “trickle charge” the battery, which is a slow charge. And then re-check. If the reading is over 12. 9 volts, you have excessive voltage. Turn on the high beams to remove excessive voltage surface charge. Over voltage may be an indication the alternator is over charging the battery. While you have the voltmeter handy, you may also want to do load testing.
A battery with a volt reading less than 9. 6 volts means the battery is sulfated and not holding/accepting the charge. Alternatively, you can get the battery tested at an auto parts store or a repair shop. [4] X Expert Source Jason ShackelfordAuto Technician Expert Interview. 11 June 2019. They usually test your battery at no charge. [5] X Expert Source Jason ShackelfordAuto Technician Expert Interview. 11 June 2019. Home diagnosis is rather difficult and not very accurate. [6] X Expert Source Jason ShackelfordAuto Technician Expert Interview. 11 June 2019.
