How to Check a 12V Lead Battery

Check your 12V lead battery to ensure maximum performance.

A 12V lead battery is generally used to power larger devices and commonly used in automobiles. Regularly check the battery to ensure it is functioning properly; this will help in the maintenance of your devices.

Things You'll Need

• Voltmeter

Instructions

Instructions

1. Turn on your car headlamps. Keep them on for at least three to five minutes. This process helps to remove any residual charge that was remaining on the battery, and to provide a more precise voltmeter result.

2. Measure the voltage setting with the voltmeter. Take the meter's positive lead and attach it to the battery's positive terminal, then take the negative lead and connect it to the battery's negative terminal. A voltage of at least 12.7 volts indicates the battery is maximally charged and functioning properly. A voltage reading of 12.2 volts and below indicates the battery is only partially charged.

3. Remove the caps from each battery cell, then take the hydrometer and place it inside the battery so that the tube-end is in contact with the battery fluid. Press on the rubber bulb to obtain a fluid sample in order to measure the gravity measurement. Make sure to do this for each cell of your battery.

4. Check the gravity level. If the gravity is at least 1.265, this means the battery is maximally charged. Once the gravity drops to 1.225 or below, there is a loss of charge. It is important for the gravity in each cell to remain within 0.05 of each other.

References

• Battery Basics
• How to Use a Voltmeter