How to Do a Car Battery Check: Recommended Power Levels

January 27, 2012

In order to ensure optimal car battery life, it’s imperative you perform a regular car battery check. In the following paragraphs, you will find a number of items to check when performing this regular car battery check.


With a car battery, volts or voltage, is the most important descriptor of the condition of the battery. Using a voltmeter, you should check the voltage regularly. With the engine off, and nothing turned on, your battery should be maintaining a minimum of 11.5 to 12 volts. Additionally, full load voltage should also be checked in order to determine whether your car battery still has usable life left in it. For this test, you will need a helper to crank the car over while you measure the voltage. If the voltage drops below ten volts while cranking, it will not last much longer.

Electrolyte Level

In order to produce an electrical current, your car’s battery requires a minimum level of electrolytes. If the electrolyte level is allowed to remain below optimal levels, this will seriously degrade output and car battery life. If the level of electrolyte is low, refill the battery with distilled water.

Specific Gravity

Another measure of your battery’s ability to produce acceptable levels of power is specific gravity, the description of which is beyond the scope of this article. A basic definition is the ratio of the density of a given fluid when compared to water. A hydrometer is used when performing the car battery check. The hydrometer is calibrated by color, green being acceptable.

Charging Voltage

While not really being a measure of the condition of your car’s battery, charging voltage will determine how long your battery will maintain the required voltage levels. With the engine running, use your voltmeter to check the voltage present at the battery terminals. This should be between 12.5 and 13.8 volts. Anything over 14 volts means you should check the regulator in your alternator, or you may over charge the battery and ruin it in a short amount of time.

Checking a car’s battery isn’t difficult and should be done at a minimum of twice a year. The preceding paragraphs have described a number of items to check on a regular basis to ensure optimal battery life.