: 1600x891 px
: July 2, 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.
When to Change Your Car's Battery. There are several signs that indicate the battery in your car is failing and needs to be replaced. Sluggish engine cranking and unusual electrical problems like flickering headlights are telltale signs of trouble, though they may also indicate problems with your car's alternator. You should also replace your battery if it is bulging or has a rotten egg smell.