1. Turn off the car.
2. Wear safety glasses. Locate the battery.
3. Turn on the digital multi -meter, plug the black wire to the middle and the red wire to DC volts.
4. Find the plus ( + ) sign on the battery (usually marked in red)
5. Put the red wire from the multi-meter on the plus ( + ) sign. Put the black wire from the multi-meter on the negative ( – ) terminal of the battery.
6. Observe a voltage reading. It should be over 12.6 but under 13. If it’s over 13, turn on the headlights for 10 seconds.
7. Start the car. The voltage should be 14-15. If it is, your charging system and alternator are OK. Under 14, you have a problem, over 15 the battery is potentially explosive, shut the car off immediately
8. If your vehicle is a newer one, and the voltage does not come up right away, turn on the headlights and watch for the voltage to come up to 13 – 15. If it does your car is OK.