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How to Check an Auto Battery
by Anthony Smith
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Overview
A car owner who has a car that does not start or has difficulty starting often immediately points to the battery as the problem. This may or may not do be the root cause, as there are other parts that can be at fault. In order to determine whether you should replace your auto battery or look elsewhere, a series of tests can be performed to thoroughly evaluate it.
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Step 1
Inspect the case of the battery for cracks and look over the terminals for any damage. If either of these situations exists, you will need to replace your battery.
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Step 2
Take the caps off the top of a battery that is not sealed and check the fluid level. The fluid should be covering all of the plates within the battery before you proceed with testing.
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Step 3
Run the vehicle or put it on a charger so that the battery has had the opportunity to have a full charge put in it. Remove any surface charge that may be on the battery by switching on the headlights for a couple of minutes.
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Step 4
Obtain the manufacturer's specifications sheet for the battery for reference during testing. This documentation came with the battery when it was purchased new, or you may find it at the company web site.
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Step 5
Use a hydrometer and take a specific gravity reading of each cell in the battery. Inexpensive hydrometers are available at any auto parts stores. Insert the tip of the hydrometer in the cell, squeeze the bulb at the top, and then release it so that the electrolyte is drawn up inside. Read from the scale printed on the side, and then refer to the spec sheet to see how it compares.
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Step 6
Take a voltage reading by connecting the voltmeter or multimeter to the terminals of the battery. Again refer to the spec sheet to see if it meets standards.
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Step 7
Hook your battery up to a load testing device and follow the instructions to perform a load test. This type of test reveals when a battery has an interior defect. If your battery fails this test or any of the previous tests, you should replace it.
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- Battery charger (optional)
Manufacturers spec sheet for the battery being checked
Hydrometer
Voltmeter or multimeter
Digital load tester
- Battery charger (optional)
- Manufacturers spec sheet for the battery being checked
- Hydrometer
- Voltmeter or multimeter
- Digital load tester
