How to Test 1.5 Volt Batteries with a Voltmeterby Anthony Smith
Many of the batteries that are commonly used in toys and electronic devices are 1.5 volt alkaline batteries. These batteries--which are commonly known as A, AA, AAA, C, and D--are different in size but all carry the same voltage. If your household is like many others, there are a number of these batteries lying around and you may have lost track of which ones are good and which ones no longer carry a charge. You can use a voltmeter to quickly test them.
Turn on the voltmeter and set the range of the meter to 2 volts DC.
Set the battery on a flat stable surface so that it doesn't roll away when you let go of it. You will need both hands to test the battery.
Place the positive lead (usually red) from the voltmeter on the positive terminal of the battery. The positive terminal of the battery is located on the end that has a "+" symbol marked on it.
Place the negative lead (usually black) from the voltmeter on the negative terminal of the battery. The negative terminal of the battery is located on the end that has a "-" symbol marked on it.
Take note of the voltage reading on the voltmeter. A brand new, fresh battery may show a voltage as high as 1.58 volts. Batteries that show a voltage of less than 1.3 volts may begin to exhibit decreased performance, and batteries with less than 1.0 volts should be replaced.