: 2226x1447 px
: June 26, 2018
The test procedure is quite simple. Set the meter to read DC volts, and set the correct range if needed. Some meters will select the correct range automatically. Nearly all meters will come with instructions on how to set them to read DC volts. Next, connect the meter across the vehicle battery, positive (+) to positive (+) and negative (-) to negative (-). With the engine running at a moderate idle - say 1200 to 1500 RPM, the meter should read approximately 13.8 to 14.8 volts and be steady. If the reading is substantially outside these figures and all other items mentioned have been tested and verified good, then the alternator is likely defective.
If the car's dashboard battery light comes on, you might be able to make it home or to a service facility for a repair. The car will continue running as long as some juice is left in the battery, but if the charging system isn't working or you have a bad alternator, your car's engine will stop running once the battery is drained. If you turn off the engine, you won't be able to restart it if the battery doesn't have enough charge left to power the engine's starter motor.