How to Check a 9V Battery

Nine-volt batteries are rechargeable, the charge becomes low after continual use. You would want to check your 9V battery to see if the battery is completely dead or just needs to be recharged. Nine-volt batteries are commonly placed in small electronic devices that require higher voltage that compact batteries can't provide.

1. Place your 9V battery on a flat surface to can see both positive and negative terminals. A flat surface will stabilize the battery for easier placement of the voltmeter's caps. It is important to get the correct reading when testing your 9V battery.


2. Set your voltmeter between five and 10 volts. You want your battery's voltage in between these numbers, so you will know how long to charge the battery or if it needs to be charge at all. Charging your battery too much will cause it to overcharge or shorten the life of future charges.


3. Place the voltmeter's caps on the respective terminals. The black cap goes to the positive terminal, and the red cap goes on the negative terminal. The caps should click when snapped onto the right terminal. Sit the voltmeter beside the 9V battery before testing the battery.


4. Turn the voltmeter on while its sitting beside the 9V battery. The voltmeter will display the current charge of your 9V battery. Anything below 9V means it needs to be recharged. A reading of 10V would indicate that the battery is overcharged. An overcharged battery is dangerous and could cause and explosion of battery acid. This could be a sign of the defective 9V battery.